2020-12-21. Habitability and the Evolution of Life Under Our Magnetic Shield. By Manasvi Lingam, Eos/AGU. Excerpt: …The existence of a global magnetic field raises questions about how it affects habitability and life. This is a question wide in scope, and the discussion here is limited to only a couple of salient effects. It is commonly thought that magnetic fields are necessary to protect planetary atmospheres from erosion by the solar wind, which hastens the acceleration and escape of atmospheric particles through electromagnetic interactions. But how valid is this premise? …There is promising evidence that Earth’s geodynamo initiated as early as 4.2 billion years ago and that the crystallization of Earth’s inner core, which paved the way for the geodynamo of today, occurred more than half a billion years ago. Although the changes in Earth’s magnetic field wrought by these transitions were likely profound, the concomitant effects on our planet’s biosphere are much less clear. Earth’s organisms must have been affected to some degree, but fathoming the magnitude and nature of these repercussions necessitates further research synthesizing knowledge from geology, astronomy, plasma physics, microbiology, evolutionary biology, and other disciplines. By resolving the riddle of whether Earth’s magnetic field played a significant role in modulating the evolution of life, we will be better positioned to consider the related question of whether a magnetic field is necessary for a planet to be habitable in the first place…. [https://eos.org/science-updates/habitability-and-the-evolution-of-life-under-our-magnetic-shield] See also The Herky-Jerky Weirdness of Earth’s Magnetic Field and A Field Guide to the Magnetic Solar System
2020-12-16. China lands its Moon rocks in Inner Mongolia. By Paul Voosen, Science Magazine. Excerpt: China’s Chang’e-5 mission made a triumphant return around 1 p.m. EST today, landing in the middle of the night on the dark frozen plains of Inner Mongolia, Chinese state media reported. The capsule’s return marks the first time China has collected rocks from the Moon—and the first time any nation has accomplished the feat since 1976. The 3-week-long mission was the most complicated in the history of China’s robotic space exploration program, involving a lunar landing, furious scooping and drilling of up to 2 kilograms of grit, and then an ascent and rendezvous with an orbiter, which carried the samples back to Earth. The China National Space Administration, typically secretive with its missions, showed growing confidence in its space program, with live broadcasts of the rocket launch and return of its sample capsule, which glowed bright white from its heat in the infrared cameras that spotted it. Chang’e-5 sampled near Mons Rümker, a 70-kilometer-wide volcanic mound on the Moon’s near side, which may have erupted as recently as about 1.3 billion years ago…. Dating that volcanic material will help inform age estimates for the entire Solar System, and, if it is indeed young, it will raise questions about how the Moon retained so much heat for so long. …Chinese officials have promised to share the precious cargo internationally…. [https://www.sciencemag.org/news/2020/12/china-lands-its-moon-rocks-inner-mongolia]. See also China Brings Moon Rocks to Earth, and a New Era of Competition to Space, by Steven Lee Myers and Kenneth Chang, The New York Times.
2020-12-07. Japan’s Hayabusa2 capsule lands with carbon-rich asteroid samples. By Dennis Normile, Science Magazine. Excerpt: Japan has once again retrieved samples from a distant asteroid, which scientists will scrutinize for clues about the ancient delivery of water and organic molecules to Earth. The return capsule of the Hayabusa2 mission—about the size and shape of a wok—parachuted to a landing in the red desert sand of Woomera, Australia, in the early morning of 6 December, after a nearly 5.3-billion-kilometer trip to the asteroid Ryugu. A helicopter team homed in on a radio beacon and found the capsule intact. Launched in 2014 by the Institute of Space and Astronautical Science of the Japan Aerospace Exploration Agency (JAXA), Hayabusa2 spent 18 months circling Ryugu, making remote observations of the diamond-shaped rubble pile. It also released several tiny rovers that hopped on the surface gathering data. After identifying safe spots amid the boulders, the craft made two fleeting touchdowns to grab samples, once from the surface and again after blasting a crater to expose subsurface materials. The goal was to collect 100 milligrams of carbon-rich soil and rock fragments. Just how much material was collected won’t be known until the sample container—the “treasure box”—is opened in clean room facilities in Tokyo this week…. [https://www.sciencemag.org/news/2020/12/japan-s-hayabusa2-capsule-lands-carbon-rich-asteroid-samples]
2020-11-20. Moon May Hold Billions of Tons of Subterranean Ice at Its Poles. By Jerald Pinson, Eos/AGU. Excerpt: New research indicates that if even a moderate amount of the water delivered by asteroids to the Moon was sequestered, the lunar poles would contain gigaton deposits (1 billion metric tons) of ice in sheltered craters and beneath its surface. …“We looked at the entire time history of ice deposition on the Moon,” said Kevin Cannon, a planetary scientist at the Colorado School of Mines in Golden and lead author of the new study in the AGU journal Geophysical Research Letters. Cannon and his team used conservative estimates for the amount of water that asteroids were likely to contain upon impact with the Moon and how much of it was likely to be retained once the dust had settled. …“If the very oldest regions have been stable and accumulating ice for billions of years, then some could have very substantial deposits, but they might be buried up to 10 meters deep or more,” Cannon said…. [https://eos.org/research-spotlights/moon-may-hold-billions-of-tons-of-subterranean-ice-at-its-poles]
2020-11-16. Famed meteorite reveals early water on Mars—and an early outer space bombardment. By Paul Voosen. Excerpt: With just 15 grams of the 4.4-billion-year-old “Black Beauty” meteorite [from Mars] discovered in 2011 in the western Sahara, [Martin Bizzarro’s] team has revealed a record of asteroid impacts and volcanic eruptions spanning nearly all of martian history. One of the most surprising findings: After Mars underwent a pummeling early in its life, all went quiet—even during a time, nearly 4 billion years ago, when our Solar System was thought to have suffered a cataclysmic assault…. [https://www.sciencemag.org/news/2020/11/famed-meteorite-reveals-early-water-mars-and-early-outer-space-bombardment].
2020-11-12. Martian dust storms parch the planet by driving water into space. By Paul Voosen, Science Magazine. Excerpt: …Martian dust storms are common, but every decade or so, for reasons unknown, a monstrous one goes global, veiling the planet. The storms can be a mortal threat to exploration: The one in 2018 killed off NASA’s Opportunity rover by coating its solar panels in dust. But now, researchers say the storms may also be one of the culprits in the ultimate martian cold case: how the once-wet planet lost its water. Fossilized rivers and deltas etched across Mars suggest water flowed there billions of years ago. Most of it must have somehow escaped to space—yet researchers thought water vapor could not travel high in the frigid, thin atmosphere without condensing into snow and falling back to the surface. New data from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) orbiter, published today in Science, show how churning dust storms may in effect pump water into space. “These escape processes are an effective way to make Mars dry,” says Anna Fedorova, a planetary scientist at the Space Research Institute of the Russian Academy of Sciences…. [https://www.sciencemag.org/news/2020/11/martian-dust-storms-parch-planet-driving-water-space] See also the Maven Mission (NASA Goddard) MAVEN Infographic: Martian Dust Storms Accelerate Water Loss.
2020-10-26. The Moon may hold much more water than we think. By Sid Perkins, Science Magazine. Excerpt: Scientists have long suspected the Moon holds sizable reserves of water, secreted as ice in the deep cold of permanently shadowed craters near the poles. Two new studies tell us more about the possible extent of those reserves. One suggests the shadowy polar caches may cover an area equivalent to the states of Connecticut and Massachusetts combined; the other reveals traces of water elsewhere on the Moon’s surface, trapped in rocks or between the grains of lunar soil. …A 2008–09 orbital expedition detected the signature of water in shadowy lunar hollows. But how much is there? To find out, Paul Hayne, a planetary scientist at the University of Colorado, Boulder, and his colleagues estimated the number and size of permanently shadowed polar regions, where temperatures remain below –163°C. …the team calculated that the Moon’s polar regions host about 40,000 square kilometers of permanently shadowed areas that could contain water, from kilometers-wide craters to shallow depressions in the meteorite-gouged terrain, they report today in Nature Astronomy. …Just last week, NASA announced a $47 million commercial contract to send an ice-seeking drill to the Moon in 2023. A second study follows tantalizing evidence that there may be water elsewhere on the Moon. …Casey Honniball, a lunar scientist at NASA’s Goddard Space Flight Center, and colleagues …found that each kilogram of lunar soil along two narrow swaths of the Moon’s surface contains between 100 milligrams and 400 milligrams of water, or about one raindrop’s worth, the team reports today in Nature Astronomy. Almost all of that water, they note, would be locked in shadowed areas between grains of lunar soil, or trapped in glassy materials created when micrometeorites smacked the lunar surface…. [https://www.sciencemag.org/news/2020/10/moon-may-hold-much-more-water-we-think]
2020-10-26. NASA’s SOFIA Discovers Water on Sunlit Surface of Moon. NASA RELEASE 20-105. Excerpt: NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) has confirmed, for the first time, water on the sunlit surface of the Moon. This discovery indicates that water may be distributed across the lunar surface, and not limited to cold, shadowed places. …Previous observations of the Moon’s surface detected some form of hydrogen, but were unable to distinguish between water and its close chemical relative, hydroxyl (OH). Data from this location reveal water in concentrations of 100 to 412 parts per million – roughly equivalent to a 12-ounce bottle of water – trapped in a cubic meter of soil spread across the lunar surface. The results are published in the latest issue of Nature Astronomy. …As a comparison, the Sahara desert has 100 times the amount of water than what SOFIA detected in the lunar soil. …the discovery raises new questions about how water is created and how it persists on the harsh, airless lunar surface. …Whether the water SOFIA found is easily accessible for use as a resource remains to be determined. Under NASA’s Artemis program, the agency is eager to learn all it can about the presence of water on the Moon in advance of sending the first woman and next man to the lunar surface in 2024 and establishing a sustainable human presence there by the end of the decade. …SOFIA…Flying at altitudes of up to 45,000 feet, this modified Boeing 747SP jetliner with a 106-inch diameter telescope reaches above 99% of the water vapor in Earth’s atmosphere to get a clearer view of the infrared universe. …SOFIA was able to pick up the specific wavelength unique to water molecules, at 6.1 microns, and discovered a relatively surprising concentration in sunny Clavius Crater. “Without a thick atmosphere, water on the sunlit lunar surface should just be lost to space,” said Honniball, who is now a postdoctoral fellow at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Yet somehow we’re seeing it. Something is generating the water, and something must be trapping it there.” [see ideas for where the water comes from]…. [https://www.nasa.gov/press-release/nasa-s-sofia-discovers-water-on-sunlit-surface-of-moon/] See also articles in the The Washington Post [https://www.washingtonpost.com/science/2020/10/26/water-on-the-moon/] and The New York Times [https://www.nytimes.com/2020/10/26/science/moon-ice-water.html]
2020-10-20. NASA’s OSIRIS-REx Spacecraft Successfully Touches Asteroid. NASA RELEASE 20-103. Excerpt: NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft unfurled its robotic arm Tuesday, and in a first for the agency, briefly touched an asteroid to collect dust and pebbles from the surface for delivery to Earth in 2023. This well-preserved, ancient asteroid, known as Bennu, … offers scientists a window into the early solar system as it was first taking shape billions of years ago and flinging ingredients that could have helped seed life on Earth. If Tuesday’s sample collection event, known as “Touch-And-Go” (TAG), provided enough of a sample, mission teams will command the spacecraft to begin stowing the precious primordial cargo to begin its journey back to Earth in March 2021. Otherwise, they will prepare for another attempt in January…. See also New York Times article [https://www.nytimes.com/2020/10/21/science/nasa-osiris-rex.html] [https://www.nasa.gov/press-release/nasa-s-osiris-rex-spacecraft-successfully-touches-asteroid]
2020-10-19. Dune Universe Inspires Titan’s Nomenclature. By JoAnna Wendel, Eos/AGU. Excerpt: Frank Herbert’s Dune tells the story of Paul Atreides, a son of a noble family sent to the hostile desert planet Arrakis to oversee the trade of a mysterious drug called melange (nicknamed “spice”), which gives its consumers supernatural abilities and longevity. …Arrakis Planitia—belongs to the second-largest moon in our solar system, Titan. Arrakis is a vast, undifferentiated plain of sand, but not sand as we know it. Titan’s sand is made of large organic molecules, which would make it softer and stickier, said Mike Malaska, a planetary scientist…. …Malaska likes to imagine that Titan’s hydrocarbon sand, which is actually referred to as tholin, or complex organic gunk, could double as the infamous spice at the center of Dune’s expansive narrative arc. …Arrakis isn’t the only name from the Dune novels that adorns Titan’s geological features. …There’s Buzzell Planitia, named after the “punishment planet” used by an ancient order of women with supernatural abilities. There’s Caladan Planitia, named after the home planet of Dune’s main hero, Paul Atreides. There’s Salusa Labyrinthus, named after a prison planet. And more. …And, of course, there are the dunes. Titan’s dune fields circle the moon’s 16,000-kilometer-long equator. The moon has more dunes than Earth has deserts. …Planetary scientists don’t name features until there’s a scientific need for them, Lopes said. A theme must first be chosen, whether it’s mythical birds for interesting areas on the asteroid Bennu, or gods of fire for volcanoes on Jupiter’s moon Io (Lopes named two of these, Tupan and Monan, after deities of indigenous cultures in her home country of Brazil). There are other literary features across the solar system, like Mercury’s craters named after famous artists and writers. Although Herbert was originally inspired by sand dunes of the Oregon coast, Malaska imagines that Herbert—and his many readers—could have also been imagining Mars, the only desert-like planet we knew of around the time Dune was published, in 1965…. [https://eos.org/geofizz/dune-universe-inspires-titans-nomenclature]
2020-10-08. A NASA mission is about to capture carbon-rich dust from a former water world. By Paul Voosen, Science Magazine. Excerpt: OSIRIS-REx is ready to get the goods. On 20 October, after several years of patient study of its enigmatic target, NASA’s $800 million spacecraft will finally stretch out its robotic arm, swoop to the surface of the near-Earth asteroid Bennu, and sweep up some dust and pebbles. The encounter, 334 million kilometers from Earth, will last about 10 seconds. If it is successful, OSIRIS-REx could steal away with up to 1 kilogram of carbon-rich material from the dawn of the Solar System for return to Earth in 2023. Since OSIRIS-REx (short for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) arrived in 2018, Bennu has yielded surprises…. Despite the logistical challenge, the boulders contain a prize: veins of carbonate minerals thicker than your hands, the team reports in one of six studies published today in Science and Science Advances. The minerals, which precipitate out of hot water, popped out of data gathered during a close flyby of light-colored boulders near the target site, called Nightingale. Researchers believe the veins grew in channels of fluid circulating within Bennu’s parent body, a larger planetesimal thought to have formed beyond Jupiter’s orbit soon after the dawn of the Solar System 4.56 billion years ago, before being smashed apart in the asteroid belt within the last billion years. …the presence of so much carbonate “suggests large-scale fluid flow, possibly over the entire parent body,” says Hannah Kaplan, a planetary scientist at Goddard who led the work…. [https://www.sciencemag.org/news/2020/10/nasa-mission-about-capture-carbon-rich-dust-former-water-world]
2020-09-30. Simulations Reveal How Planetary Impacts Affect Atmosphere. By Frank Tavares, NASA. Excerpt: The histories of planets across our solar system and beyond are filled with collisions and transformations. New research is helping scientists understand how colossal impacts, like the one with Earth thought to have formed the Moon, are impacting the atmospheres of rocky planets.In the animation above, a Mars-like mass grazes an Earth-like mass, replicating the traditional theory for the impact that formed the Moon. Some atmosphere is lost, accompanied by a shockwave…. [https://www.nasa.gov/image-feature/ames/planetary-impact-simulations]
2020-09-25. Moon safe for long-term human exploration, first surface radiation measurements show. By Adam Mann, Science Magazine. Excerpt: …China’s Chang’e 4 lander has made the first detailed measurements of the intense radiation that blasts the lunar surface and found that it’s safe for human exploration. …The robotic Chang’e 4 made history last year when it touched down in Von Kármán crater on the Moon’s far side, bringing a suite of instruments along for the ride. One of these was a new dosimeter…. The device measured hourly radiation rates and found that astronauts would be exposed to roughly 200 times the radiation levels as people on Earth, they report today in Science Advances. The dosimeter’s placement inside the Chang’e 4 probe provides partial shielding, much as an astronaut’s spacesuit would to their body, so the findings are quite applicable to human explorers, Wimmer-Schweingruber says. The measured dose is about five to 10 times what passengers on an intercontinental flight from New York City to Frankfurt, Germany, receive when the plane is above parts of the protective atmosphere, Wimmer-Schweingruber says. …NASA is legally prohibited from increasing the risk of its astronauts dying from cancer by more than 3%, and these levels remain below that. What’s more, the researchers calculated that Moon bases covered with at least 50 centimeters of lunar soil would be sufficient to protect them. A deeper chamber shielded with about 10 meters of water would be enough to protect against occasional solar storms, which can cause radiation levels to spike dramatically. (Between the Apollo 16 and 17 missions, the Sun flared up in a way that could have caused radiation sickness, vomiting, and possibly death had astronauts been unprotected in space at the time.) Such a chamber would need to be reachable within 30 minutes, the amount of advanced warning time that is now possible with monitoring satellites…. [https://www.sciencemag.org/news/2020/09/moon-safe-long-term-human-exploration-first-surface-radiation-measurements-show]
Scientists spot potential sign of life in Venus atmosphere. By Marisa Iati and Joel Achenbach, The Washington Post. Excerpt: An international team of astronomers has detected a rare molecule in the atmosphere of Venus that could be produced by living organisms, according to a study published Monday. The discovery instantly puts the brightest planet in the night sky back into the conversation about where to search for extraterrestrial life. The researchers made clear this is not a direct detection of life on Venus. But the astronomical observations confirmed the highly intriguing presence of the chemical phosphine near the top of the acidic clouds that blanket the planet. Phosphine is a simple molecule produced on Earth by bacteria and through industrial processes. As a result, it is on the list of molecules — oxygen being another — considered by scientists to be potential “biosignatures” of life on Earth-sized planets whose atmospheres can be viewed through telescopes…. [https://www.washingtonpost.com/technology/2020/09/14/venus-life-evidence/] See also New York Times article, Life on Venus? Astronomers See a Signal in Its Clouds [https://www.nytimes.com/2020/09/14/science/venus-life-clouds.html] and article from MIT Technology Review, We need to go to Venus as soon as possible [https://www.technologyreview.com/2020/09/16/1008478/venus-soon-as-possible-phosphine-clouds-astrobiology-life-veritas-davinci/] Also New York Times article, Missions to Venus: Highlights From History, and When We May Go Back [https://www.nytimes.com/2020/09/14/science/venus-spacecraft-life.html] and On Venus, Cloudy With a Chance of Microbial Life [https://www.nytimes.com/2020/09/19/science/venus-planets-microbes-life.html]
2020-09-10. NASA announces it’s looking for companies to help mine the moon. By Christian Davenport, The Washington Post. Excerpt: The space agency announced Thursday it is looking for companies to collect rocks and dirt from the lunar surface, and then sell them to NASA, as part of a technology development program that would eventually help astronauts “live off the land.” …The announcement is yet another step in NASA’s Artemis project to set up a permanent presence on and around the moon and eventually go to Mars, where astronauts would need to be able to use the resources there. In a blog post, Bridenstine said the effort would fully comply with the Outer Space Treaty of 1967, which says that no country may lay sovereign claim to the moon or other celestial bodies…. [https://www.washingtonpost.com/technology/2020/09/10/moon-mining-nasa-search/]
2020-08-15. How Do You Solve a Moon Mystery? Fire a Laser at It. By Katherine Kornei, The New York Times. Excerpt: The moon is drifting away. Every year, it gets about an inch and a half farther from us. Hundreds of millions of years from now, our companion in the sky will be distant enough that there will be no more total solar eclipses. For decades, scientists have measured the moon’s retreat by firing a laser at light-reflecting panels, known as retroreflectors, that were left on the lunar surface, and then timing the light’s round trip. But the moon’s five retroreflectors are old, and they’re now much less efficient at flinging back light. To determine whether a layer of moon dust might be the culprit, researchers devised an audacious plan: They bounced laser light off a much smaller but newer retroreflector mounted aboard a NASA spacecraft that was skimming over the moon’s surface at thousands of miles per hour. And it worked. These results were published this month in the journal Earth, Planets and Space [https://earth-planets-space.springeropen.com/articles/10.1186/s40623-020-01243-w]…. [https://www.nytimes.com/2020/08/15/science/moon-lasers-dust.html]
2020-08-10. Planet Ceres is an ‘ocean world’ with sea water beneath surface, mission finds. By The Guardian. Excerpt: Dwarf planet, believed to be a barren space rock, has an ‘extensive reservoir’ of brine beneath its surface, images show. The dwarf planet Ceres – long believed to be a barren space rock – is an ocean world with reservoirs of sea water beneath its surface, the results of a major exploration mission showed on Monday. Ceres is the largest object in the asteroid belt between Mars and Jupiter and has its own gravity, enabling the Nasa Dawn spacecraft to capture high-resolution images of its surface. Now a team of scientists from the United States and Europe have analysed images relayed from the orbiter, captured about 35km (22 miles) from the asteroid. They focused on the 20-million-year-old Occator crater and determined that there is an “extensive reservoir” of brine beneath its surface…. [https://www.theguardian.com/science/2020/aug/10/planet-ceres-ocean-world-sea-water-beneath-surface] See also article Dwarf planet Ceres is an ocean world with salty water under the surface, NASA mission finds [https://www.cnn.com/2020/08/11/world/ceres-dwarf-planet-ocean-scn-trnd/] by Ashley Strickland, CNN
2020-07-28. Exploring the Solar System. By Jonathan Corum. Excerpt: Three missions to Mars this summer — from NASA, China and the United Arab Emirates — will join dozens of active and inactive spacecraft beyond Earth’s orbit. [A comprehensive listing of solar system missions…. [https://www.nytimes.com/interactive/2020/science/exploring-the-solar-system.html].
2020-07-25. Why the ‘Super Weird’ Moons of Mars Fascinate Scientists. What’s the big deal about little Phobos and tinier Deimos? By Robin George Andrews, The New York Times. Excerpt: our planetary neighbor is adorned with two moons: puny Phobos, a lumpy mass 17 miles across; and diminutive Deimos, just 9 miles long. Their names in ancient Greek may mean “fear” and “dread’, but the aesthetics of these Lilliputian space potatoes inspire anything but. …the desire to visit Phobos and Deimos was galvanized by their deeply mysterious nature. “They’re super weird, confusing and interesting,” said Abigail Fraeman, a planetary scientist studying Mars, Phobos and Deimos at NASA’s Jet Propulsion Laboratory. …they look like asteroids foreign to the red planet but behave like byproducts of Mars’ early, impact-laden history. And if that Japanese mission manages to grab some samples and decode the chemistry of the mangled moons, we might be able to discover their origins. In doing so, we won’t just gain a better understanding of Mars’ ancient past. We will also be able to peer back in time to the chaos that shaped the early solar system. …both moons orbit the equator in a neat-and-tidy circular fashion, which suggests they coalesced from a disk of debris that danced around a young Mars. It’s difficult to capture an asteroid and have it “wind up in this beautiful, symmetric, circular orbit,” said Jeffrey Plaut, the project scientist for the Mars Odyssey mission. Mars, having a tenth of Earth’s mass, has a relatively weak gravitational pull, so it seems improbable that it would be able to capture asteroids zipping by, said Tomohiro Usui, a robotic planetary exploration expert at the Japan Aerospace Exploration Agency. But if they formed from a debris disk launched up from Mars after a colossal impact, Deimos should be orbiting closer to Mars than it is today. …“They just shouldn’t exist,” said Dr. Fraeman. “They don’t make any sense.”… [https://www.nytimes.com/2020/07/25/science/mars-moons-phobos-deimos.html]
2020-07-14. A Month of Milestones for Mars Missions. By Kimberly M. S. Cartier, Eos/AGU. Excerpt: The United Arab Emirates (UAE) hopes to kick off a new decade of Mars exploration as it launches the Emirates Mars Mission and its orbiter, Hope. Hope, or Al Amal, is the first space exploration mission from an Arab state. It will be joined in its journey to Mars by China’s Tianwen-1 and the United States’ Mars 2020 mission later in July. …The Hope probe is a weather satellite that will create a global map of Mars’s weather and atmospheric dynamics up through the exosphere. One of its science goals is to understand how near-surface weather leads to loss of atmospheric hydrogen and oxygen, a key to understanding Mars’s evolution from warm and wet to cold and arid. …Tianwen-1 is an all-in-one orbiter, lander, and rover and could make China only the second country (after the United States) to successfully land on Mars. The plan is for Tianwen-1 first to orbit Mars and assess possible landing sites in Utopia Planitia and then to deploy the mission’s surface components. The landing platform will deploy the rover in a design similar to China’s Chang’e missions to the Moon. …NASA’s Mars 2020 rover, Perseverance, will land in Jezero Crater, a dry lake bed that contains evidence of ancient water flows and perhaps signs of ancient microbial life. …The rover will also carry a small helicopter, Ingenuity, which will be the first attempted powered flight on another planet…. [https://eos.org/articles/a-month-of-milestones-for-mars-missions] See also New York Times article Meet the 3 Spacecraft Heading to Mars This Summer.
2020-07-08. With first spacecraft to Red Planet, United Arab Emirates poised to join elite Mars club. By Sedeer El-Showk, Science Magazine. Excerpt: The United Arab Emirates (UAE), a small Persian Gulf nation, is on the cusp of a big breakthrough: joining the United States, the Soviet Union, Europe, and India in the elite club of nations that have successfully sent spacecraft to Mars. On 15 July, the Emirates Mars Mission (EMM)—also known as the Hope satellite—is set to launch on a Japanese rocket, arriving at the Red Planet in February 2021. Planners hope the mission will boost UAE industry and science capacity while also delivering sorely needed data on the martian atmosphere. …Most of the six spacecraft now at Mars are in polar orbits that only offer views of the surface at fixed times of day. But Hope will be inserted into an inclined orbit that provides a view of any given point at a different time on each orbit. A camera and infrared spectrometer will collect data about dust, moisture, and ozone in the lower atmosphere, while an ultraviolet spectrometer will measure carbon monoxide, hydrogen, and oxygen in the upper atmosphere. …The mission has given equal weight to building capacity for space science research in the UAE. “This mission created expertise in the country in areas we never had expertise in before,” says Amiri, who was a program engineer on the UAE’s DubaiSat satellites before becoming EMM science lead and, later, UAE’s minister of State for Advanced Science…. [https://www.sciencemag.org/news/2020/07/first-spacecraft-red-planet-united-arab-emirates-poised-join-elite-mars-club]. See also New York Times article [https://www.nytimes.com/2020/07/14/science/mars-united-arab-emirates.html]
2020-07-02. How NASA’s new rover will search for signs of ancient life on Mars. By Kelso Harper, Joel Goldberg, Science Magazine. Excerpt: [See movie also] If NASA realizes its midsummer dream, a spacecraft will blast off from Cape Canaveral, Florida, sometime between 30 July and 15 August, destined to ignite the next generation of Mars exploration. The mission aims to deliver the space agency’s latest rover, Perseverance, to an uncharted crater known as Jezero—an ancient lake bed that could offer a window into Mars’s climatic history. Perseverance will carry many tools and instruments, including a small helicopter and a novel array of 43 sample tubes, robotic arms, and multiple drills, which will bore into the martian surface for chalk-size cores of rock and soil. The cores will eventually make their way back to Earth in a sample return campaign, a joint effort between NASA and the European Space Agency. Should they contain organic compounds, they may indicate the existence of past microorganisms—in other words, evidence of ancient life on the Red Planet…. [https://www.sciencemag.org/news/2020/07/how-nasa-s-new-rover-will-search-signs-ancient-life-mars] See also Martian Chronicler, Science Magazine 2020 June 26 article by Paul Voosen [http://science.sciencemag.org/content/368/6498/1416]
2020-06-25. NASA’s new rover will collect martian rocks—and clues to planet’s ancient climate. By Paul Voosen, Science Magazine. Excerpt: NASA’s newest Mars rover, Perseverance, is going back in time to the bottom of a vanished lake. If all goes well, in February 2021 it will land in Jezero crater and pop the dust covers off its camera lenses. Towering in front of it, in all likelihood, will be a 60-meter cliff of mudstone: the edge of a fossilized river delta. These lithified martian sediments could hold answers to urgent questions about the earliest days of Earth’s chilly, parched neighbor: How did this pintsize planet, so distant from a faint young Sun, support liquid water on its surface? How much water was there, and how long did it persist? And did Mars ever spawn life?…. [https://www.sciencemag.org/news/2020/06/nasa-s-new-rover-will-collect-martian-rocks-and-clues-planet-s-ancient-climate]
2020-06-25. Mars mission would put China among space leaders. By Dennis Normile, Science Magazine. Excerpt: NASA’s Perseverance rover may have company on the Red Planet. China aims to leap to the front ranks in planetary exploration with an ambitious Mars mission, its first independent bid to reach the planet. Tianwen-1—“quest for heavenly truth”—consists of not only an orbiter, but also a lander and a rover, a trifecta no other nation has accomplished on its first Mars bid. “A successful landing would put China among elite company,” says Mason Peck, an aerospace engineer at Cornell University…. [https://www.sciencemag.org/news/2020/06/mars-mission-would-put-china-among-space-leaders]
2020-06-23. Mars Is About to Have Its ‘Wright Brothers Moment’. By Kenneth Chang, The New York Times. Excerpt: As part of its next Mars mission, NASA is sending an experimental helicopter to fly through the red planet’s thin atmosphere…. [https://www.nytimes.com/2020/06/23/science/mars-helicopter-nasa.html]
2020-06-22. Small Worlds With Lava Oceans Might Have Given Us Meteorites. By Jonathan O’Callaghan, The New York Times. Excerpt: Researchers propose a new model to explain the formation of most of the meteorites that make it to Earth. “Droplets of fiery rain.” That’s how Henry Clifton Sorby, a 19th-century British mineralogist, described the tiny spheres called chondrules found within meteorites. Chondrules are such dominant features of these meteorites that they are called chondrites, and they account for 86 percent of meteorites that have been found on Earth. Their origin, however, remains a mystery. …Now some scientists think they have a new answer to this rocky enigma: The chondrites may have formed in an unusual event during a narrow window of time in the early solar system. The findings [https://www.sciencedirect.com/science/article/abs/pii/S0019103517302476], presented at a virtual meeting of the American Astronomical Society this month by William Herbst and James Greenwood of Wesleyan University in Connecticut, paint a strange picture of what parts of the solar system were like before the planets we know began to form. …Their results suggest a crowded landscape in the early inner solar system, with a nascent sun surrounded by thousands of planetesimals, the rocky building blocks of planets, each tens of miles or so in size. On some of their surfaces were oceans of lava that reached temperatures of more than 3,000 degrees Fahrenheit. When even smaller rocky bodies — asteroids — got close to these young worlds, they would have been briefly heated by this lava. That rapidly melted portions of these objects, which then passed by and cooled to form chondrules…. [https://www.nytimes.com/2020/06/22/science/meteorites-chondrites-chondrules.html]
2020-06-16. Baby planets are born exceptionally fast, study suggests. By Adam Mann, Science Magazine. Excerpt: Planets are forming around young stars far faster than scientists expected, arising in a cosmic eye blink of less than half a million years, according to a new study. …Planets coalesce from massive disks of gas and dust that surround newborn stars. But detecting these embryonic worlds is difficult because both the star and the disk shine far brighter than any tiny planet. To find out how much material is available for planet formation, researchers have used the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to weigh the disks around young stars between 1 million and 3 million years old. Past studies found that some lacked the mass to form even a single Jupiter-size world. The results suggested astronomers were either overlooking some hidden reservoir of material or they were looking too late in the planet-forging process, after growing protoplanets had already vacuumed up much of the material. The answer, says Łukasz Tychoniec, a graduate student at Leiden Observatory and lead author of the new paper [https://arxiv.org/abs/2006.02812], is that “we need to look earlier instead of [looking] for missing mass.”… [https://www.sciencemag.org/news/2020/06/missing-mass-planet-formation-found-young-disks-gas-and-dust]
2020-06-05. Sunburned Surface Reveals Asteroid Formation and Orbital Secrets. By Megan Sever, Eos/AGU. Excerpt: Newly analyzed high-resolution images from the Hayabusa2 landing on the near-Earth asteroid Ryugu revealed a reddish hue to surface materials. Scientists interpret that coloration to be a result of a brief orbital excursion close to the Sun. When combining this information with previously collected data from Ryugu, scientists can now paint a clearer picture of how and when the asteroid formed, how its orbit has changed over time, and what its surface looks like…. [https://eos.org/articles/sunburned-surface-reveals-asteroid-formation-and-orbital-secrets]
2020-01-08. How many of our comets come from alien solar systems? By Eva Frederick, Science Magazine. [https://www.sciencemag.org/news/2020/01/how-many-our-comets-come-alien-solar-systems] F Excerpt: Comets are generally thought to originate in our Solar System, made up of the leftover gas and rocks thrown out as the planets formed. The recent arrival of two interstellar objects—a rock named ‘Oumuamua and a flashy comet called Borisov—have challenged that assumption. Tom Hands, an astrophysicist at the University of Zurich’s Institute for Computational Science and his co-author Walter Dehnen at Ludwig Maximilian University of Munich used mathematical models to estimate just how many long-period comets—those that take 200 years or longer to circle the Sun—could be interstellar visitors. …We estimated from the study that there should be 100,000 ‘Oumuamua-style small rocks and 100 Borisov-style comets in the Solar System. Making far more conservative estimates for how long these objects would survive in the Solar System [shorter than 10 million years], we would expect 20,000 ‘Oumuamuas or 20 comets. The majority of these things would have highly eccentric orbits with periods of a few hundred thousand years, meaning they spend the vast majority of their time far, far out beyond the orbit of Pluto….
2019-11-26. Meet Hygiea, the Smallest Dwarf Planet in Our Solar System. By Javier Barbuzano, Eos/AGU. [https://eos.org/articles/meet-hygiea-the-smallest-dwarf-planet-in-our-solar-system] Excerpt: Around 2 billion years ago, two large rock bodies hit each other in the main asteroid belt, a region between the orbits of Mars and Jupiter populated by fragments of rocks of various sizes. The impactor, with a size ranging from 75 to 150 kilometers in diameter, hit a body at least 4 times larger. Astronomers have known about this impact for a long time because it created a whole family of asteroids in the main asteroid belt, formed by the celestial body Hygiea and almost 7,000 smaller asteroids that have similar orbits. Hygiea itself has been considered an asteroid since it was discovered in 1849 by Italian astronomer Annibale de Gasparis. With a diameter just over 430 kilometers, it is the fourth-largest object in the main asteroid belt. New observations obtained with the Very Large Telescope (VLT), located in Chile and operated by the European Southern Observatory, have revealed that Hygiea is also round. Determining the shape of Hygiea doesn’t have any practical implications for its orbit or behavior, but it’s enough to propel Hygiea from asteroid to dwarf planet, according to current scientific classifications. There are four conditions that solar system objects must meet to be classified as dwarf planets: They must orbit the Sun, not be a satellite orbiting another body, not be massive enough to clear their orbit from other objects, and have a round shape due to their own gravity….
2019-11-25. Curiosity Rover Reveals Oxygen Mystery in Martian Atmosphere. By Sarah Stanley, Eos/AGU. [https://eos.org/research-spotlights/curiosity-rover-reveals-oxygen-mystery-in-martian-atmosphere] Excerpt: The Martian atmosphere is thin and cold and consists mostly of carbon dioxide. Although certainly unsuitable for humans, Martian air could hold clues to whether other life-forms live—or once lived—on the Red Planet. Now Trainer et al. report the first measurements of the five major components of the Martian atmosphere captured over several seasonal cycles. …On average, the data revealed, the equatorial Martian atmosphere consists of 95% carbon dioxide, 2.59% nitrogen, 1.94% argon, 0.161% oxygen, and 0.058% carbon monoxide. However, throughout the year, some of these concentrations vary widely because of seasonal freezing of carbon dioxide at the planet’s poles, which periodically removes much of this gas from the atmosphere. Seasonal polar freezing—and subsequent thawing—of carbon dioxide also causes atmospheric pressure to rise and fall throughout the year. …The researchers also found unexpected patterns in seasonal and year-to-year oxygen concentrations that cannot be explained by any known atmospheric or surface processes on Mars. The authors suggest that these variations could be due to chemical reactions in surface rocks but note that further research is needed to solve this mystery….
2019-11-13. How Enceladus got its water-spewing tiger stripes. By Adam Mann, Science Magazine. [https://www.sciencemag.org/news/2019/11/how-enceladus-got-its-water-spewing-tiger-stripes] Excerpt: Researchers say they have solved a long-standing mystery about Saturn’s tiny, frozen moon Enceladus: why its south pole features long, water-spewing geysers known as tiger stripes. The study could also help explain why these unique formations aren’t seen on any other satellite in the solar system. Enceladus became a star attraction in 2005, when NASA’s Cassini mission photographed enormous jets of water ice and vapor emanating from four parallel slashes near its south pole. Since then, researchers have detected organic molecules and hydrogen in the jets—potential food for microbes—making Enceladus one of the top destinations in the search for life elsewhere in the Solar System. …As it orbits around Saturn, Enceladus experiences gravitational tidal forces that squeeze and heat it. …According to the new study, led by Douglas Hemingway of the Carnegie Institution for Science in Washington, D.C., as the moon cooled over time and some of the ocean water refroze, the new ice generated strain that built up in the surface until it broke. “It’s like your pipes freezing on a cold day,” says Nimmo, who was not involved in the study. …That first fissure, extending down to the ocean, allowed a geyser to spray snow on its two flanks. The weight of this extra material produced more strains. …Enceladus is the sole known possessor of tiger stripes (although controversial evidence suggests Jupiter’s moon Europa sports similar watery spouts). Its small size might explain why. The moon’s low gravity means that fractures can bust all the way through its outer shell and persist. On a more massive moon, the researchers say in their study, the weight of heavier ice would tend to squeeze cracks shut…. See also The New York Times article, How an Icy Moon of Saturn Got Its Stripes [https://www.nytimes.com/2019/12/09/science/enceladus-stripes-moon.html]
2019-09-18. Veil of dust from ancient asteroid breakup may have cooled Earth. By Joshua Sokol, Science Magazine. [https://www.sciencemag.org/news/2019/09/veil-dust-ancient-asteroid-breakup-may-have-cooled-earth] Excerpt: Faced with a dangerously warming world, would-be geoengineers have dreamed up ways to quickly turn down the heat. One proposed technique: spreading a veil of dust that would sit in space or Earth’s atmosphere and reflect sunlight. Researchers say they have now found evidence for a similar experiment that played out naturally, 466 million years ago, when an asteroid out in space exploded into bits. Dust from the breakup blanketed the planet, says Birger Schmitz, a geologist at Lund University in Sweden, plunging it into an ice age that was soon followed by an explosion in animal life. The ancient episode offers both encouragement and caution for geoengineers. If Schmitz is right, it dramatically demonstrates how dust can cool the planet. But the deep freeze is a lesson in potential unintended consequences….
2019-08-08. Jupiter’s annual portrait is a beaut. By Robert Sanders, UC Berkeley News. [https://news.berkeley.edu/story_jump/jupiters-annual-portrait-is-a-beaut/] Excerpt: Just as families record the changing faces of their kids as they grow older, the Hubble Space Telescope each year captures the changing faces of the solar system’s four colorful gas-giant planets. The newest photo in that yearbook is a portrait of Jupiter taken June 27 that reveals clouds swirling in the planet’s turbulent atmosphere that are painted with a color palette more intense than seen in previous years. Mike Wong, an associate researcher in UC Berkeley’s Department of Astronomy and one of three members of the Hubble team taking the photos, was most intrigued by a mysterious color change around Jupiter’s equator: The formerly white equatorial belt has become orangish. And, surprisingly, Red Spot Jr., a planet that was red the last time it was photographed, has turned white. It is now back to the way it looked at its formation in 2000, before it flipped to red in 2006…. [See time-lapse movie!]
2019-06-13 Jupiter’s Great Red Spot (GRS) is shrinking.
• comparison image between Pioneer’s visit(s) and a more recent ground-based image – http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=21649
• HST images – http://hubblesite.org/image/3368/news/20-jupiter
• animation of GRS shrunk another 20% or so – http://spaceweather.com/archive.php?view=1&day=08&month=06&year=2019
• Christopher Go – http://astro.christone.net/jupiter/
• Anthony Wesley (see 2019 Apr) – http://www.acquerra.com.au/astro/gallery/jupiter/
• Damian Peach (2019) – http://www.damianpeach.com/jupiter.htm
2019-04-05. A Japanese spacecraft may have just blown a crater in a distant asteroid. By Dennis Normile, Science Magazine. [https://www.sciencemag.org/news/2019/04/japanese-spacecraft-may-have-just-blown-crater-distant-asteroid] Excerpt: Japan’s Hayabusa2 mission continued its unprecedented explorations today by apparently creating an artificial crater in an asteroid, a space exploration first. Officials confirmed that the operation to fire a projectile into asteroid Ryugu went smoothly, though as of early evening Japan time they were still trying to confirm whether a crater had actually been formed. …Developed by the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science in Sagamihara, Hayabusa2 was launched in December 2014 and traveled 3.2 billion kilometers through space before reaching its home position 20 kilometers away from Ryugu, a diamond-shaped asteroid about 1 kilometer by 900 meters in size orbiting between Earth and Mars. The mission’s objective is to collect samples both from Ryugu’s surface and its interior and return them to Earth for analyses that should yield information on the materials that existed in the early solar system and give clues about the formation and evolution of planets. The samples might also provide evidence for the theory that asteroids and comets are one source of Earth’s water and its amino acids, the building blocks of life. Scientists are particularly eager to get material from beneath the surface that has not been affected by eons of space weathering. In February, Hayabusa2 briefly landed on Ryugu and fired a tantalum pellet into the surface that likely knocked about 10 grams of rock fragments into a collection horn….
2019-03-19. The Asteroid Was Shooting Rocks Into Space. ‘Were We Safe in Orbit?’ By Kenneth Chang and Shannon Stirone, The New York Times. [https://www.nytimes.com/2019/03/19/science/bennu-ryugu-asteroids.html] Excerpt: HOUSTON — The asteroid Bennu, with the shape of a spinning top, turns out to be extremely rugged. That is going to make it difficult for a NASA spacecraft, Osiris-Rex, to vacuum up a sample to take back to Earth. It was designed to collect sand and gravel, not boulders. In addition, Bennu is shooting back. “We are seeing Bennu regularly eject material into outer space,” said Dante Lauretta, Osiris-Rex’s principal investigator…. The NASA spacecraft, which launched in 2016, entered orbit around Bennu on Dec. 31. It is not the only spacecraft from Earth exploring an asteroid. Hayabusa2, launched by Japan’s space agency in 2014, began orbiting the asteroid Ryugu last year. Its mission is also to collect samples for return to our planet for study, …. Both missions have found that the objects they are studying have terrain much more jagged than anticipated. But while Hayabusa2 already collected its first sample from Ryugu’s surface last month, the particles erupting from Bennu posed an additional challenge for the Osiris-Rex mission….
2019-03-18. How Ultima Thule Is Like a Sticky, Pull-Apart Pastry. By Kenneth Chang, The New York Times. [https://www.nytimes.com/2019/03/18/science/ultima-thule-new-horizons.html] Excerpt: …New Horizons traveled some 4 billion miles to take a close-up look at this 22-mile-long world in the solar system’s icy Kuiper belt beyond Neptune; it is officially designated as 2014 MU69 and nicknamed Ultima Thule. …a small shard that has been frozen and almost unchanged since it formed 4.5 billion years ago. Ultima Thule was … full of surprises. The shape turned out to be unlike anything seen in the solar system. …two objects that at some stage touched and stuck together, like a snowman. Then the scientists discovered that the two lobes of Ultima Thule were not spherical, but more like lumpy pancakes. The larger lobe is also flatter than the smaller one. …a change from older ideas of planetary formation: that objects called planetesimals grew slowly and steadily in size. Ultima Thule suggests an alternative scenario in which a bunch of similarly sized objects merged together over a shorter interval of time. …With the flattened shape of the two lobes of Ultima Thule, another surprise was that the rotational axis of each were nearly parallel to each other. William B. McKinnon of Washington University in St. Louis, a co-investigator on the mission, said the finding strongly suggested that the two lobes formed out of one rotating cloud of icy particles. When the two finally touched, the collision was slow, about 2 meters per second, or 4.5 miles per hour. “Which, if you take a brisk walk into a wall, you’ll find out what that’s like,” Dr. McKinnon said. “But I don’t recommend you do that.”…
2019-03-05. There’s probably another planet in our solar system. By MIT Technology Review. [https://www.technologyreview.com/s/613060/theres-probably-another-planet-in-our-solar-system/] Excerpt: When it comes to exploring the solar system, astronomers have an embarrassing secret. Despite 400 years of stargazing, they have discovered only two large objects that would have been unknown to the ancients: Uranus in 1781 and Neptune in 1846. That’s not for lack of trying. The possibility of an unknown planet just beyond observational reach has attracted astronomers like moths to a flame. A few have been successful. Several astronomers together discovered Neptune after noticing that the other planets were being gravitationally nudged by an unknown mass. Neptune didn’t entirely resolve these discrepancies, and the hunt continued into the 20th century, culminating in Pluto’s discovery in 1930. But Pluto turned out to be so small that it couldn’t account for the nudging. Indeed, it was later humiliatingly demoted to a “dwarf planet.” …
2019-02-22. Update: Japanese spacecraft safely lands and leaves asteroid surface in effort to collect samples. By Dennis Normile, Science Magazine. [https://www.sciencemag.org/news/2019/01/japans-asteroid-mission-faces-breathtaking-touchdown] Excerpt: *Update, 22 February, 6:33 a.m.: Japan’s Hayabusa2 spacecraft successfully executed a challenging touchdown on asteroid Ryugu today at about 7:30 a.m. Japan time. Officials from the Japan Aerospace Exploration Agency confirmed that during an autonomous operation Hayabusa2 landed momentarily within a target site just 6 meters wide and fired a steel pellet into the surface of the asteroid in hopes of scattering fragments into a collection horn. Mission planners hoped to collect 10 grams of material, but the amount won’t be known for sure until the sample container is returned to Earth in 2020. Hayabusa2 could make two more touchdowns to gather additional samples. [4 January story previewing its historic touchdown plans:] YONAGO, JAPAN—Japan’s Hayabusa mission made history in 2010 for bringing back to Earth the first samples ever collected on an asteroid. But the 7-year, 4-billion-kilometer odyssey was marked by degraded solar panels, innumerable mechanical failures, and a fuel explosion that knocked the spacecraft into a tumble and cut communications with ground control for 2 months. When planning its encore, Hayabusa2, Japan’s scientists and engineers were determined to avoid such drama. They made components more robust, enhanced communications capabilities, and thoroughly tested new technologies…. See also [https://www.scientificamerican.com/article/in-search-of-lifes-origins-japans-hayabusa-2-spacecraft-lands-on-an-asteroid/] In Search of Life’s Origins, Japan’s Hayabusa 2 Spacecraft Lands on an Asteroid. …and 2019-02-26. A Target Before Shooting Ryugu. By Nola Taylor Redd, Eos/AGU. [https://eos.org/articles/a-target-before-shooting-ryugu]
2019-01-28. Apollo May Have Found an Earth Meteorite on the Moon. By Kimberly M. S. Cartier, Eos/AGU. [https://eos.org/articles/apollo-may-have-found-an-earth-meteorite-on-the-moon] Excerpt: The meteorite may have been blasted off of Earth during an impact, mixed with lunar rocks, and brought back to Earth 4 billion years later by astronauts. A rock sample brought back by Apollo 14 may contain the first evidence of Earth material on the Moon. New analysis of zircon grains in one lunar sample suggests that the zircon formed under conditions typical in Earth’s crust and not on the Moon. …“I expect there could be a bit of controversy because this is the first of its kind,” [Jeremy] Bellucci said. “Hopefully,” he said, “it inspires a search for more Earth materials and further analyses on these samples.”…
2019-01-25. How Long Is a Day on Saturn? By Nadia Drake, The New York Times. [https://www.nytimes.com/2019/01/25/science/saturn-day-length.html] Excerpt: For decades, it was a nagging mystery — how long does a day last on Saturn? Earth pirouettes around its axis once every 24 hours or so, while Jupiter spins comparatively briskly, once in roughly 9.8 Earth-hours. And then there is Venus, a perplexingly sluggish spinner that takes 243 Earth-days to complete a full rotation. With Saturn, it turns out the answer rippled in plain view, in the planet’s lustrous rings. After reading small, spiraling waves in those bands, sculpted by oscillations from Saturn’s gravity, scientists reported this month in the Astrophysical Journal that one Saturnian day is a mere 10 hours, 33 minutes and 38 seconds long, measured in Earth time. …Saturn has been stubbornly secretive about its days. Its buttery clouds don’t bear helpful markings that scientists might use to track the planet’s rotation, and they can’t easily use its nearly vertical magnetic axis — as they have for Jupiter’s more off-kilter alignment — to gather clues about the planet’s interior. … Not until the Cassini spacecraft swooped, flipped and twirled through the Saturn system did scientists realize that the answer was outside the planet itself, etched into its icy rings. As Saturn spins, its internal vibrations inscribe telltale signatures in its rings; studying those markings is now termed “kronoseismology,” from kronos, the Greek name for Saturn, and seismo, for quakes and vibrations….
2019-01-17. Moon’s craters reveal recent spike in outer space impacts on Earth. By Paul Voosen, Science Magazine. [https://www.sciencemag.org/news/2019/01/moon-s-craters-reveal-recent-spike-outer-space-impacts-earth] Excerpt: It has long been thought that as the solar system grows older and stodgier, the number of asteroids and comets colliding with Earth and other planets has steadily gone down. But a new study reveals what appears to be a dramatic 2.5 times increase in the number of impacts striking Earth in the past 300 million years. …Scientists used a thermal camera on NASA’s Lunar Reconnaissance Orbiter to examine the number of large, heat-retaining rocks in the moon’s craters; those rocks are eventually ground to dust by minute meteorite impacts. By looking at previously dated craters, these rocks have been established as a reliable dating technique—the more intact the rocks, the younger the crater. In the new study, the team found a surprising abundance of young craters, seemingly matching the number on Earth. That means, they write today in Science, that in its modern geological history, Earth is much better at retaining the features of impact craters than once thought, and that the recent proliferation coincides with an actual increase in the number of bombarding asteroids or comets. But scientists still don’t know what caused the uptick. Perhaps several large asteroids collided or otherwise broke up some 300 million years ago, their chunks slowly migrating out from the asteroid belt to bombard Earth, the researchers say. And that could have included the giant impact, 66 million years ago, that wiped out most of the dinosaurs…. See also New York Times article, What Happened to Earth’s Ancient Craters? Scientists Seek Clues on the Moon’s Pocked Surface. [https://www.nytimes.com/2019/01/17/science/craters-meteors-moon.html]
2019-01-03. Chinese spacecraft successfully lands on moon’s far side and sends pictures back home. By Dennis Normile, Science Magazine.
[https://www.sciencemag.org/news/2019/01/chinese-spacraft-successfully-lands-moons-far-side-and-sends-pictures-back-home]. Excerpt: China’s Chang’e-4 spacecraft successfully landed on the far side of the moon this morning Beijing time, accomplishing a worldwide first in lunar exploration. China’s state media confirmed that touchdown occurred at 10:26 a.m. local time; later in the day, the China National Space Administration released the first close-ups of the surface of the far side, taken by Chang’e-4 after it landed. …Chang’e-4 was launched on 8 December 2018 from the Xichang Satellite Launch Center in Sichuan province. The landing site is in the Von Kármán crater in the South Pole-Aitken Basin. The basin was likely formed by a giant asteroid impact that might have brought material from the moon’s upper mantle to the surface; studying samples taken there might offer scientists the chance to learn more about the composition of the body’s interior. The moon’s far side has a much thicker, older crust and is pockmarked by more and deeper craters than the near side, where large dark plains called maria, formed by ancient lava flows, have erased much of the cratering. Chang’e-4’s observations could give clues to the processes behind the differences…. See also 2018-0102. The Far Side of the Moon: What China and the World Hope to Find. By Shannon Hall, New York Times [https://www.nytimes.com/2019/01/02/science/far-side-moon.html]; 2019-01-02. ‘New Chapter’ in Space Exploration as China Reaches Far Side of the Moon. By Steven Lee Myers and Zoe Mou, The New York Times. [https://www.nytimes.com/2019/01/02/world/asia/china-change-4-moon.html]; 2019-01-03. Chang’e-4 Lands on the Moon. By Jonathan Corum, The New York Times. [https://www.nytimes.com/interactive/2019/01/03/science/china-change-4-moon-landing.html]; 2019-01-04. Lander Gives First Look at Moon’s Farside, by Kimberly M. S. Cartier Eos/AGU [https://eos.org/articles/lander-gives-first-look-at-moons-farside]
2019-01-02. Japan’s asteroid mission faces ‘breathtaking’ touchdown. By Dennis Normile, Science Magazine. [https://www.sciencemag.org/news/2019/01/japans-asteroid-mission-faces-breathtaking-touchdown] Excerpt: “By looking at the details of every asteroid ever studied, we had expected to find at least some wide flat area suitable for a landing,” says Yuichi Tsuda, Hayabusa2’s project manager at the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science (ISAS), which is headquartered in Sagamihara. Instead, when the spacecraft reached Ryugu in June 2018—at 290 million kilometers from Earth—it found a cragged, cratered, boulder-strewn surface that makes landing a daunting challenge. The first sampling touchdown, scheduled for October, was postponed until at least the end of this month, and at a symposium here on 21 and 22 December, ISAS engineers presented an audacious new plan to make a pinpoint landing between closely spaced boulders….
2019-01-02. NASA’s New Horizons Mission Reveals Entirely New Kind of World. By New Horizons Mission. [http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20190102] For GSS A Changing Cosmos chapter 7. Excerpt: Scientists from NASA’s New Horizons mission released the first detailed images of the most distant object ever explored — the Kuiper Belt object nicknamed Ultima Thule. Its remarkable appearance, unlike anything we’ve seen before, illuminates the processes that built the planets four and a half billion years ago. “This flyby is a historic achievement,” said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado. “Never before has any spacecraft team tracked down such a small body at such high speed so far away in the abyss of space. New Horizons has set a new bar for state-of-the-art spacecraft navigation.” The new images — taken from as close as 17,000 miles (27,000 kilometers) on approach — revealed Ultima Thule as a “contact binary,” consisting of two connected spheres. End to end, the world measures 19 miles (31 kilometers) in length. The team has dubbed the larger sphere “Ultima” (12 miles/19 kilometers across) and the smaller sphere “Thule” (9 miles/14 kilometers across). The team says that the two spheres likely joined as early as 99 percent of the way back to the formation of the solar system, colliding no faster than two cars in a fender-bender…. See also 2019-01-02. New Horizons reveals a ‘snowman’ at the edge of the solar system. By Paul Voosen, Science Magazine. [https://www.sciencemag.org/news/2019/01/new-horizons-reveals-snowman-edge-solar-system] and Surviving encounter beyond Pluto, NASA probe begins relaying view of Kuiper belt object [https://www.sciencemag.org/news/2019/01/surviving-encounter-beyond-pluto-nasa-probe-begins-relaying-view-kuiper-belt-object]; 2019-01-03. What We’ve Learned About Ultima Thule From NASA’s New Horizons Mission. By Kenneth Chang, The New York Times. [https://www.nytimes.com/2019/01/03/science/ultima-thule-pictures-new-horizons.html]; 2019-01-02. NASA Unveils Image of the Most Distant Object Ever Visited. New York Times/ Reuters video [https://www.nytimes.com/video/science/space/100000006287885/nasa-ultima-thule-images.html]; 2019-01-04. New Horizons Sends First Looks of 2014 MU69, by Kimberly M. S. Cartier Eos/AGU [https://eos.org/articles/new-horizons-sends-first-looks-of-2014-mu69].; 2019-01-25. A Sharper Picture of Ultima Thule From NASA’s New Horizons. By Kenneth Chang, The New York Times. [https://www.nytimes.com/2019/01/25/science/ultima-thule-photo.html]
2019-01-01. New Horizons flyby of Kuiper Belt object Ultima Thule (2014 MU69). NASA. [http://pluto.jhuapl.edu/News-Center/] New Horizons is the superb spacecraft mounted with instruments that gave us all those rich, rich images and data in its flyby of Pluto in July of 2015. Soon those exquisite instruments can be focused on yet another world in our Solar System, this time a Kuiper Belt object! Ultima is 100 times smaller than Pluto, but was Likely formed 4.5 or 4.6 billion years ago, 4 billion miles from the Sun. It’s been at near absolute zero temperature ever since, so it’s likely the best sample of the ancient solar nebula ever studied. Will Ultima turn out to be a collection smaller bodies? Will it have an atmosphere? Will it have rings? Will it have moons? Any of that could be possible, and soon we’ll know the answers to these questions. Get ready to wish New Year to New Horizons.
2018-12-12. Martian methane—spotted in 2004—has mysteriously vanished. By Paul Voosen, Science Magazine. [https://www.sciencemag.org/news/2018/12/martian-methane-spotted-2004-has-mysteriously-vanished]. Excerpt: Scientists first detected traces of [methane]—a critical indicator of life on Earth—in the planet’s atmosphere decades ago. But today, researchers reported that a European satellite hasn’t spotted a single trace of methane. The finding, if it holds up, could complicate scientific dreams that martian microbes might be spewing the gas in the planet’s subsurface. …scientists suspect that hundreds of tons of organic carbon pour into the martian atmosphere each year from solar system dust, reacting with solar radiation to form methane, say John Moores, a planetary scientist at York University in Toronto, Canada. “Where is all that carbon going?”….
2018-12-12. Martian methane—spotted in 2004—has mysteriously vanished. By Paul Voosen, Science Magazine. [https://www.sciencemag.org/news/2018/12/martian-methane-spotted-2004-has-mysteriously-vanished]. Excerpt: Scientists first detected traces of [methane]—a critical indicator of life on Earth—in the planet’s atmosphere decades ago. But today, researchers reported that a European satellite hasn’t spotted a single trace of methane. The finding, if it holds up, could complicate scientific dreams that martian microbes might be spewing the gas in the planet’s subsurface. …scientists suspect that hundreds of tons of organic carbon pour into the martian atmosphere each year from solar system dust, reacting with solar radiation to form methane, say John Moores, a planetary scientist at York University in Toronto, Canada. “Where is all that carbon going?”….
2018-12-04. Megapixels: Watch NASA’s OSIRIS-REx spacecraft zoom in on its asteroid target. By Jillian Mock, Popular Science. [https://www.popsci.com/megapixels-nasa-asteroid-bennu] Excerpt: On Monday, a NASA spacecraft reached the near-Earth asteroid Bennu, kicking off a research mission that could help us unlock secrets of the early solar system and, hopefully, the start of life on Earth. The spacecraft, named OSIRIS-REx (because Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer doesn’t exactly roll off the tongue), has been beaming pictures of its approach to the asteroid all the way, allowing us to get a really close look for the first time. …After a two year journey traveling to reach the asteroid’s orbit between Earth and Mars, the spacecraft is now less than 12 miles from Bennu. Following a few initial passes to get a sense of spin, mass, and shape, OSIRIS-REx will drop in close enough to start orbiting the asteroid in its weak field of gravity. If this happens as planned in January 2019, Bennu will become the smallest object NASA has ever orbited. …OSIRIS-REx will spend another two years with its celestial dancing partner. While circling Bennu, which is about as wide as the Empire State Building is tall, the spacecraft will snap photos of the asteroid while 3-D mapping its surface and measuring temperature, rock mineral content, and x-rays emissions. OSIRIS-REx won’t ever land on its rocky target. But in July 2020, it will also reach out a mechanical arm and tap the asteroid’s surface to take a physical sample of whatever it finds there. The spacecraft will send this sample back to Earth, which, if successful, will be the first specimen collected from an asteroid and returned to our planet…. See also New York Times article [https://www.nytimes.com/2018/12/03/science/osiris-rex-bennu-asteroid-arrival.html]
2018-11-26. NASA’s InSight Mission Has Touched Down on Mars to Study the Red Planet’s Deep Secrets. By Kenneth Chang, The New York Times. [https://www.nytimes.com/2018/11/26/science/nasa-insight-mars-landing.html] Excerpt: The InSight lander, NASA’s latest foray to the red planet, has landed. …In the months ahead, InSight will begin its study of the Martian underworld, listening for tremors — marsquakes — and collect data that will be pieced together in a map of the interior of the red planet and help would help scientists understand how Mars and other rocky planets formed. …“We can basically use Mars as a time machine to go back and look at what the Earth must have looked like a few tens of millions of years after it formed,” said Bruce Banerdt, the principal investigator of the mission. … The main scientific part of the mission will not begin for a few months. …InSight will use two main instruments: a dome-shape package containing seismometers and a heat probe that is to burrow about 16 feet down. … Two identical spacecraft known as Mars Cube One, or MarCO for short, launched with InSight in May. MarCO A and B then separated from InSight’s cruise stage and have since been trailing behind it. …The MarCO spacecraft relayed InSight’s telemetry to Earth flawlessly, enabling the immediate celebration. “This has been a fantastic day for spacecraft great and small,” said Andrew Klesh, the chief engineer for the CubeSats…. See also Science Magazine article NASA lander survives harrowing descent to surface of Mars [https://www.sciencemag.org/news/2018/11/nasa-lander-will-plunge-mars-today-harrowing-6-minute-descent]
2018-11-26. How to Land on Mars. By Jonathan Corum, The New York Times. [https://www.nytimes.com/interactive/2018/11/25/science/insight-how-to-land-on-mars.html]
2018-11-19. NASA’s next Mars rover will land in Jezero crater, which once hosted a lake and a river delta. By Paul Voosen, Science Magazine. [https://www.sciencemag.org/news/2018/10/nasas-next-mars-rover-could-explore-former-mineral-springs-and-fossil-river-delta] Excerpt: Update: NASA today announced the destination for its next Mars rover, due for launch in 2020. The agency said it would send the rover to the 50-kilometer-wide Jezero crater, which billions of years ago harbored a lake that half filled the 500-meter-deep basin. The crater also contains within its rim a fossilized river delta, the sediments from a river that spilled into the crater—a promising place to search for evidence of past life. [see photo in article; https://www.sciencemag.org/sites/default/files/styles/inline__699w__no_aspect/public/ca_1012NID_Delta_Jezer_Crater_online.jpg?itok=0xVirXxA] “Getting samples from this unique area will revolutionize how we think about Mars and its ability to harbor life,” Thomas Zurbuchen, NASA’s associate administrator for science in Washington, D.C., said in a press conference. …The 2020 rover will be tasked with gathering and caching rock and soil samples for eventual return to Earth by subsequent missions….
2018-11-15. Anything faster than a brisk walk on this martian moon could send you spinning off into space. By Joshua Rapp Learn, Eos/AGU. [https://www.sciencemag.org/news/2018/11/anything-faster-brisk-walk-martian-moon-could-send-you-spinning-space] Excerpt: Walk, don’t run, on the martian moon Phobos. A new study finds that traveling faster than about 5 kilometers per hour on some regions of the Red Planet’s largest satellite could shoot you straight off into space. Phobos… is an odd duck among our solar system’s moons. It’s tiny (a fraction of a percent the size of our own moon) and is shaped like a potato; that weird shape draws gravity to different places, depending on where you are. All these features make Phobos a challenge to travel on, researchers report in Advances in Space Research. In some places, moving any faster than 5 kilometers per hour would be enough to free you from the moon’s meager gravitational pull, sending you off into space…. The fastest you could travel anywhere on Phobos would be about 36 kilometers per hour, or a little faster than a golf cart, the team finds. The findings could pose problems for planned missions to Phobos….
2018-11-12. Atacama Desert’s Unprecedented Rains Are Lethal to Microbes. By Katherine Kornei, Eos/AGU. [https://eos.org/articles/atacama-deserts-unprecedented-rains-are-lethal-to-microbes] Excerpt: Chile’s Atacama Desert is the driest place on Earth. It receives just millimeters of rain each year, on average, and its parched conditions make it a commonly used stand-in for Mars. Last year, scientists working in the Atacama were astounded to find multiple lagoons of liquid water there—the ephemeral runoff from an unusual rain event. But the rainfall that created these ponds didn’t result in a bloom of life, the researchers found; it was actually lethal to the majority of microbes adapted to the extreme aridity of the Atacama. These findings have implications for future spacecraft missions that will collect samples from other planets: Incubating dry soil samples in aqueous solutions, as was done with the Viking landers on Mars in the 1970s, may have the inadvertent effect of killing microbial life. …Azua-Bustos and his team hypothesized that the microbes were killed by osmotic stress after they absorbed water. “They burst like balloons,” he said. …Not using water would represent a change from previous protocols. “The Viking experiments involved incubation of Mars soil samples in aqueous solutions,” said Fairén. The Viking landers used these solutions to determine whether any hypothetical microbes on Mars were consuming carbon-based compounds….
2018-11-01. After visits with Vesta and Ceres, asteroid-exploring Dawn spacecraft goes dark. By Paul Voosen, Science Magazine. [https://www.sciencemag.org/news/2018/10/after-visits-vesta-and-ceres-asteroid-exploring-dawn-spacecraft-about-go-dark] Excerpt: …After several missed attempts to communicate with Dawn over the past 2 days, NASA declared that the spacecraft had run out of hydrazine and reached the end of its mission. …[original coverage from 17 October]: …After an 11-year journey to Vesta and Ceres, the asteroid belt’s two largest members, NASA’s Dawn spacecraft … gave a close-up view of how the presence or absence of water can shape asteroids, will remain tumbling in orbit around Ceres for decades before ultimately crashing into it. Launched in 2007, Dawn is the only NASA mission to orbit two planetary bodies, a feat made possible by its efficient ion thrusters. In 2011, it arrived at the egg-shaped, 600-kilometer-long Vesta, orbiting for a year before departing for Ceres, where it arrived in 2015. …The two asteroids, which together account for 45% of the belt’s mass, turned out to be a tale of contrasts. Parched Vesta has a composition like the terrestrial planets, with an iron core and a dry, rocky surface carved up into canyons, craters, and mountains, remnants of past impacts and volcanism. Dawn was able to verify that a class of meteorites found on Earth are chips off of Vesta, making it a sort of “reverse sample return mission,” says Carol Raymond, the mission’s principal investigator and a planetary scientist at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. Telescopes had already found water-rich minerals on Ceres, a 900-kilometer-wide body classified as a dwarf planet because of its large size and spherical shape. Dawn revealed the remnants of a frozen ocean topped by a heavily cratered crust of clays and salts. …In its final months, Dawn settled into a tight orbit, just 35 kilometers from Ceres’s surface. The defunct craft could remain in orbit for a half-century or more….
2018-10-22. Scientists Double Down on Landing Sites for Sample-Collecting Mars Rover. By Leonard David, Science Magazine. [https://www.scientificamerican.com/article/scientists-double-down-on-landing-sites-for-sample-collecting-mars-rover/] Excerpt: NASA’s Mars 2020 mission could visit two locations where microbial life may once have thrived. For NASA’s Mars 2020 rover, now being assembled at the agency’s Jet Propulsion Laboratory for launch in July 2020, the stakes could not be much higher. The $2.4 billion nuclear-powered rover is the most complex piece of machinery to ever make a ballistic beeline for the Red Planet. And after it lands in February 2021, its completion of one high-profile objective—collecting rock samples for eventual transport back to Earth—would ensure the rover sets the course for future Mars exploration for decades to come. But first, mission planners have to decide where on Mars this ambitious machine should actually go….
2018-10-03. Japanese spacecraft drops a third rover on asteroid Ryugu. By Dennis Normile, Science Magazine. [https://www.sciencemag.org/news/2018/10/japanese-spacecraft-drops-third-rover-asteroid-ryugu] Excerpt: After successfully dropping two small hopping rovers on the surface of asteroid Ryugu last month, the Japanese spacecraft Hayabusa2 today deployed another probe with a suite of instruments that will do some serious science. Hayabusa2, which arrived at Ryugu in June after a 3.5-year journey, descended to 51 meters above the asteroid and released the Mobile Asteroid Surface Scout (MASCOT). Twenty minutes later, the asteroid’s gravity had pulled the 10-kilogram probe, 30 by 30 by 20 centimeters in size, to the surface. …MASCOT, jointly developed by the German Aerospace Center and the French National Centre for Space Studies, carries a camera, instruments to measure day-to-night thermal changes and check for magnetism, and an infrared spectral microscope to study the mineral composition and look for any evidence the asteroid once hosted water or organic molecules. MASCOT will collect data in one location, then hop to a second for another round of observations. About 16 hours after deployment, MASCOT’s batteries will run down and the observation phase of the mission will be over. Hayabusa2 itself is likely to make the first of three touchdowns on the asteroid to collect samples later this month. It will start its journey back to Earth in late 2019.
2018-09-28. Cosmic conundrum: The disks of gas and dust that supposedly form planets don’t seem to have the goods. By Adam Mann, Science Magazine. [https://www.sciencemag.org/news/2018/09/cosmic-conundrum-disks-gas-and-dust-supposedly-form-planets-don-t-seem-have-goods] Excerpt: Astronomers have a problem on their hands: How can you make planets if you don’t have enough of the building blocks? A new study finds that protoplanetary disks—the envelopes of dust and gas around young stars that give rise to planets—seem to contain orders of magnitude too little material to produce the planets. “This work is telling us that we really have to rethink our planetary formation theories,” says astronomer Gijs Mulders of the University of Chicago in Illinois, who was not involved in the research. …The brightness of radio waves emitted by dust in the disk can be used to give a reasonable estimate of its overall mass. …In the new study, astronomers led by Carlo Manara of the European Southern Observatory in Munich, Germany, used [Atacama Large Millimeter Array (ALMA)] to compare the masses of protoplanetary disks around young stars between 1 million and 3 million years old to the masses of confirmed exoplanets and exoplanetary systems around older stars of equivalent size. The disk masses were often much less than the total exoplanet mass—sometimes 10 or 100 times lower, the team will report in an upcoming paper in Astronomy & Astrophysics. …a great deal of mass, perhaps as much as 10 times what’s been observed, could be hidden in the form of pebbles, which are slightly too big to show up in such investigations….
2018-09-22. Hayabusa-2: Japan’s rovers send pictures from asteroid. By BBC News. [https://www.bbc.com/news/science-environment-45598156] Excerpt: Japan’s space agency (JAXA) has made history by successfully landing two robotic explorers on the surface of an asteroid. The two small “rovers”, which were despatched from the Hayabusa-2 spacecraft on Friday, will move around the 1km-wide space rock known as Ryugu. The asteroid’s low gravity means they can hop across it, capturing temperatures and images of the surface. …Hayabusa-2 reached the asteroid Ryugu in June this year after a three-and-a-half-year journey. …Early on Thursday morning (GMT), Hayabusa-2 began descending towards the surface of Ryugu, preparing to eject its rovers. …The 1kg rovers are equipped with wide-angle and stereo cameras to send back pictures. Spine-like projections from the edges of the hoppers are sensors that will measure surface temperatures on the asteroid. …The diamond-shaped asteroid has a blackish-coloured surface, and rotates on its axis around once every 7.5 hours. On 3 October, the mothership will deploy a lander called Mascot, which has been developed by the German Aerospace Center (DLR) together with the French Space Agency (CNES). And in late October, Hayabusa-2 will descend to the surface of Ryugu to collect a sample of rock and soil. …Further on in the mission, Japan’s space agency plans to detonate an explosive charge that will punch a crater into the surface of Ryugu. Hayabusa-2 would then descend into the crater to collect fresh rocks that have not been altered by aeons of exposure to the environment of space. These samples will be sent to Earth for laboratory studies. The spacecraft will leave Ryugu in December 2019 with the intention of returning to Earth with the asteroid samples in 2020…. See also New York Times article, Hayabusa2 Lands Two Rovers on Asteroid Ryugu.
2018-08-11. Parker Solar Probe Launches on NASA Voyage to ‘Touch the Sun’. By Kenneth Chang, The New York Times. [https://www.nytimes.com/2018/08/11/science/parker-solar-probe-launch.html] Excerpt: Atop three columns of flame at 3:31 a.m. Eastern time, NASA’s Parker Solar Probe [http://parkersolarprobe.jhuapl.edu/] lifted toward space on Sunday. The launch was the second attempt to carry the spacecraft, which NASA touts will “touch the sun” one day, into orbit after a scrub early on Saturday. The probe — which will study the sun’s outer atmosphere as well as the stream of particles known as solar wind — was carried on top of a Delta IV Heavy rocket built and operated by United Launch Alliance, a joint venture between Boeing and Lockheed Martin. It is one of the most powerful rockets currently available. …The spacecraft will eventually pass within 4 million miles of the sun’s surface, close enough to skim through the star’s outer atmosphere. …At its closest approach, the outside of the spacecraft will reach 2,500 degrees Fahrenheit, or about the melting temperature of steel. But an 8-foot-wide carbon composite shield will absorb the intense heat and keep the spacecraft and its instruments cool. The foam in the shield is so fluffy — 97 percent empty space — that it adds only 160 pounds of weight. …In total, the spacecraft will complete 24 orbits, and the mission is to end in 2025. During its later orbits, the strong pull of the sun’s gravity will accelerate the probe to 430,000 miles per hour, which will be the fastest human-made object ever….
2018-08-10. NASA’s Parker Solar Probe Is Named for Him. 60 Years Ago, No One Believed His Ideas About the Sun. By Kenneth Chang,The New York Times. [https://www.nytimes.com/2018/08/10/science/eugene-parker-solar-wind-nasa-probe.html] Excerpt: CHICAGO — It was 1958. Sputnik had launched only a year earlier…. But the beach ball-size spacecraft had no instruments to measure anything in space. …It certainly looked like the vast expanses between planets were empty. And that is what most scientists believed. But not Eugene N. Parker, then a 31-year-old, no-name professor at the University of Chicago. In a foundational paper published in The Astrophysical Journal, Dr. Parker described how charged particles streamed continuously from the sun, like the flow of water spreading outward from a circular fountain. Almost no one believed him. “The prevailing view among some people was that space was absolutely clean, nothing in it, total vacuum,” Dr. Parker recalled during an interview at his home. …The scientists who had reviewed the paper rejected his idea as ludicrous. Dr. Parker appealed to the journal’s editor, Subrahmanyan Chandrasekhar, a prominent astrophysicist also at Chicago, arguing that the reviewers had not pointed out any errors, just that they did not like the premise. Dr. Chandrasekhar overruled the reviewers. …Four years later, Dr. Parker was vindicated when Mariner 2, a NASA spacecraft en route to Venus, measured energetic particles streaming through interplanetary space — exactly what Dr. Parker had predicted. Scientists now call that stream of particles the solar wind. …Sixty years after Dr. Parker’s paper, NASA is about to launch a spacecraft that is to dive into outer wisps of the sun’s atmosphere and gather information about how our star generates the solar wind….
2018-07-27. Ancient craters on Mars reveal how the planet’s tilt has changed over time. By Katherine Kornei, Science Magazine. Excerpt: Earth is a tilted planet—it lists by 23.5°. This “obliquity” causes the North Pole to sometimes tilt toward the sun and sometimes away, giving us the seasons. Now, researchers have revealed how Mars’s obliquity has changed over the last 3.5 billion years, results that could reveal how frequently water ice and snow would have melted to liquid on the Red Planet. To conduct the study, scientists assembled computer models of Mars with different obliquities and bombarded each version of the planet with asteroids. Elliptical craters—created by asteroids hitting the planet at shallow angles—tended to be more evenly distributed over the models with larger obliquities. On more upright planets, the elliptical craters tended to cluster around the equator. By comparing their models with the distribution of more than 1500 elliptical craters on Mars’s surface, the researchers concluded that, in its past, Mars listed between 10° and 30°, similar to its present-day obliquity of 25°…. http://www.sciencemag.org/news/2018/07/ancient-craters-mars-reveal-how-planet-s-tilt-has-changed-over-time
2018-07-27. What does Mars’ lake mean for the search for life on the Red Planet? By Lisa Grossman, Science Magazine. Excerpt: The search for life on Mars just got a lot more interesting. For decades, scientists have looked at …finding regions where life could have taken root billions of years ago, when the Martian climate was warmer and wetter. But on July 25, researchers announced they had spotted signs of a large lake of liquid water hiding beneath thick layers of ice near the Red Planet’s south pole (SN Online: 7/26/18). If the lake’s existence is confirmed, we could find microbes living on Mars today. That report changes the calculus for astrobiologists who want to protect any existing extraterrestrial life from being wiped out or obscured by introduced species from Earth…. Mars landers and rovers are cleaned to strict standards to avoid any possible contamination, even “without having anything you’d even call a pond,” says astrobiologist Lisa Pratt, NASA’s planetary protection officer. “Now we have a report of a possible subglacial lake! That’s a major change in the kind of environment we’re trying to protect.” …Could anything actually live in this lake? …the low temperature cutoff for most terrestrial life is around –40° Celsius. The Martian ice sheet is about –68° C. …for the water to be liquid at such cold temperatures, it must be extremely salty. …“Even ‘extremophile’ bacteria that can live in highly salty water might not be able to survive.” But could Martians live there? “Absolutely,” Pratt says. If life arose on Mars sometime in its more life-friendly past, some organisms could have adapted to the changing climate and ended up finding the cold, salty water quite comfortable, she says…. See also Liquid water spied deep below polar ice cap on Mars (Science Magazine 2018 Jul 25) https://www.sciencenews.org/article/what-does-mars-lake-mean-search-life-red-planet
2018-07-17. Jupiter’s moon count reaches 79, including tiny ‘oddball’. By Emiliano Rodriguez Mega, Associated Press. Excerpt: Astronomers are still finding moons at Jupiter, 400 years after Galileo used his spyglass to spot the first ones. The latest discovery of a dozen small moons brings the total to 79, the most of any planet in our solar system. Scientists were looking for objects on the fringes of the solar system last year when they pointed their telescopes close to Jupiter’s backyard, according to Scott Sheppard of the Carnegie Institute for Science in Washington. They saw a new group of objects moving around the giant gas planet but didn’t know whether they were moons or asteroids passing near Jupiter. …The team is calling one of the new moons an ‘oddball’ because of its unusual orbit. Sheppard’s girlfriend came up with a name for it: Valetudo, the great-granddaughter of the Roman god Jupiter. Valetudo is in Jupiter’s distant, outer swarm of moons that circles in the opposite direction of the planet’s rotation. Yet it’s orbiting in the same direction as the planet, against the swarm’s traffic. “This moon is going down the highway the wrong way,” Sheppard said. Scientists believe moons like Valetudo and its siblings appeared soon after Jupiter formed. The planet must have acted like a vacuum, sucking up all the material that was around it. Some of that debris was captured as moons…. https://apnews.com/5604f183641342f1ad7f99f2ce665181
2018-07-02. In a first, astronomers witness the birth of a planet from gas and dust. By Daniel Clery, Science Magazine. Excerpt: In the first convincing observation of its kind, astronomers have directly imaged a newborn planet still forming around its star. The planet, hotter than any in our solar system, supports what astronomers have long believed: that such bodies are born of the disks of gas and dust that coalesce around young stars. “After decades of speculation, it’s nice to actually see one. It’s very comforting,” says astronomer Kevin Heng of the University of Bern in Switzerland, who was not involved in the work. The initial discovery was led by astronomer Miriam Keppler of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany. Since 2015, her team has been regularly surveying hundreds of young stars for signs of exoplanets with a next-generation imaging instrument called SPHERE (for Spectro-Polarimetric High-contrast Exoplanet Research), attached to the European Southern Observatory’s Very Large Telescope (VLT) on Cerro Paranal in Chile. One of those stars was PDS 70, a 10-million-year-old dwarf star about 370 light-years from Earth…. http://www.sciencemag.org/news/2018/07/first-astronomers-witness-birth-planet-gas-and-dust
2018-06-27. Japan’s new asteroid probe reaches its target after 3.2-billion-kilometer journey. By Dennis Normile, Science Magazine. Excerpt: SAGAMIHARA, JAPAN—After 3.5 years traveling 3.2 billion kilometers through space, Japan’s Hayabusa2 spacecraft officially arrived at the asteroid it will land on later this year to pick up surface and subsurface soil and rock samples and—hopefully—return them to Earth for analysis. The findings are expected to shed light on the materials that existed in the early solar system and the formation and evolution of planets and their arrangement. They might provide evidence for the theory that asteroids and comets are one source of Earth’s water and its amino acids—the building blocks of life. …Next spring, Hayabusa2 will blast a crater into Ryugu using a 2-kilogram projectile with a hardened copper nose traveling at 2000 meters per second. …Images of the impact are expected to shed light on how craters are formed on heavenly bodies. Hayabusa2 will then return to the site of the blast to collect rock samples that have not been subjected to eons of space weathering, hopefully yielding insights into the material as it was during the formation of the solar system. The craft is expected to return its samples to Earth at the end of 2020. Preliminary observations “are really thrilling,” says Seiichiro Watanabe, a project scientist at Nagoya University in Japan. The diamond-shape asteroid is about 900 meters across and rotates around its own axis every 7.5 hours or so, more slowly than other similarly sized asteroids for reasons that are not yet clear, Watanabe says. The surface is strewn with boulders larger than would be expected to have accumulated on an asteroid of its size, something that has triggered a debate among planetary scientists…. http://www.sciencemag.org/news/2018/06/japan-s-new-asteroid-probe-reaches-its-target-after-32-billion-kilometer-journey
2018-06-25. The Case of the Missing Lunar Heat Flow Data Is Finally Solved. By Sarah Stanley, Eos/AGU. Excerpt: Decades-old data analyzed for the first time suggest that astronauts’ disturbance of the Moon surface increased solar heat intake, warming the ground below. During the Apollo 15 and 17 missions, astronauts installed four temperature-sensing probes in shallow, 1.0- to 2.4-meter-deep holes drilled into the Moon. They aimed to measure how much of the Moon’s heat was lost to space, which could provide insights into the origin and the differentiation history of the Moon. The Apollo Heat Flow Experiment ran from 1971 to 1977. …In 2011, the researchers reported that they had found about 10% of the missing tapes at the Washington National Records Center in Maryland. …They found that from 1974 until the Heat Flow Experiment concluded in 1977, the lunar subsurface warmed up, with greater warming occurring at shallower depths. This continued a warming trend observed by the original researchers in data collected between 1971 and December of 1974. The measurements indicate that the observed warming began near the surface and spread downward. …Calculations from heat conduction models suggest that the timing and amount of warming seen at different depths are best explained by a rapid increase in surface temperature at the time of probe installation. This finding supports the hypothesis that disturbance of the lunar surface by astronauts’ footprints and other activities increased its roughness, reducing the amount of solar radiation reflected back to space. Thus, increased absorption of solar heat caused the observed warming…. https://eos.org/research-spotlights/the-case-of-the-missing-lunar-heat-flow-data-is-finally-solved
2018-06-07. NASA rover hits organic pay dirt on Mars. By Paul Voosen, Science Magazine. Excerpt: In its quest to find molecules that could point to life on Mars, NASA’s Curiosity rover has struck a gusher. Since Curiosity landed in 2012, it has sifted samples of soil and ground-up rock for signs of organic molecules—the complex carbon chains that on Earth form the building blocks of life. Past detections have been so faint that they could be just contamination. Now, samples taken from two different drill sites on an ancient lakebed have yielded complex organic macromolecules that look strikingly similar to the goopy fossilized building blocks of oil and gas on Earth. At a few dozen parts per million, the detected levels are 100 times higher than previous finds. Although the team cannot yet say whether these molecules stem from life or a more mundane geological process, they demonstrate that organics can be preserved for billions of years in the harsh martian surface environment, says Jennifer Eigenbrode, a biogeochemist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who led a study in this week’s Science. “We’re in a really good position to move forward looking for signs of life.” …Because ultraviolet radiation and oxidizing compounds in the martian soil would destroy any compounds exposed at the surface, Curiosity’s scientists used a robotic drill to penetrate several centimeters into the mudstone. They delivered the fresh grit to an oven inside the rover’s belly…. http://www.sciencemag.org/news/2018/06/nasa-rover-hits-organic-pay-dirt-mars
2018-05-24. This asteroid came from another solar system—and it’s here to stay. By Daniel Clery, Science Magazine. Excerpt: While astronomers around the world had their eyes fixed last year on ‘Oumuamua, a lump of rock from another planetary system that whizzed through ours, little did they know that another interstellar interloper was quietly living among us. And this one appears to have been here for billions of years. Astronomers first spotted the object, an asteroid called 2015 BZ509 that is orbiting close to Jupiter, in 2014. They knew it was unusual because it was traveling around the solar system in the opposite direction as almost everything else. …Astronomers have found other objects in “retrograde” orbits, perhaps knocked off course by passing too close to a giant planet, but 2015 BZ509’s orbit was the weirdest of all because it is also elongated and out of alignment with the planets and other bodies. To find out why, a pair of astronomers ran a series of 1 million simulations of the asteroid’s orbit, each with slightly different parameters. …researchers found a number of possible orbits that were stable and concluded it is much more likely that 2015 BZ509 is in one of them, rather than that it happened to arrive for a short-term visit. Some of those stable orbits, if wound back in time, would mean that 2015 BZ509 has been with us since the beginning of our solar system, about 4.5 billion years ago. …There is no known mechanism that could have produced 2015 BZ509 in such an orbit when the planets were forming, the researchers report today in the Monthly Notices of the Royal Astronomical Society: Letters. Instead, the asteroid must have been drifting through space and was captured by the sun’s gravity…. http://www.sciencemag.org/news/2018/05/asteroid-came-another-solar-system-and-it-s-here-stay
2018-05-07. Yes, Pluto is a planet. By David Grinspoon and Alan Stern, The Washington Post. Excerpt: Three years ago, NASA’s New Horizons, the fastest spaceship ever launched, raced past Pluto, spectacularly revealing the wonders of that newly seen world. This coming New Year’s Eve — if all goes well on board this small robot operating extremely far from home — it will treat us to images of the most distant body ever explored, provisionally named Ultima Thule. We know very little about it, but we do know it’s not a planet. Pluto, by contrast — despite what you’ve heard — is. Why do we say this? …We use “planet” to describe worlds with certain qualities. When we see one like Pluto, with its many familiar features — mountains of ice, glaciers of nitrogen, a blue sky with layers of smog — we and our colleagues quite naturally find ourselves using the word “planet” to describe it and compare it to other planets that we know and love. In 2006, the International Astronomical Union (IAU) announced an attempted redefinition of the word “planet” that excluded many objects, including Pluto. We think that decision was flawed, and that a logical and useful definition of planet will include many more worlds. We find ourselves using the word planet to describe the largest “moons” in the solar system. Moon refers to the fact that they orbit around other worlds which themselves orbit our star, but when we discuss a world like Saturn’s Titan, which is larger than the planet Mercury, and has mountains, dunes and canyons, rivers, lakes and clouds, you will find us — in the literature and at our conferences — calling it a planet. This usage is not a mistake or a throwback. It is increasingly common in our profession and it is accurate…. https://www.washingtonpost.com/news/speaking-of-science/wp/2018/05/07/yes-pluto-is-a-planet/
2018-04-18. Diamonds in a Meteorite May Be a Lost Planet’s Fragments. By Nicholas St. Fleur, The New York Times. Excerpt: In 2008, chunks of space rock crashed in the deserts of Sudan. Diamonds discovered inside one of the recovered meteorites may have come from a destroyed planet that orbited our sun billions of years ago, scientists said on Tuesday. If confirmed, they say, it would be the first time anyone has recovered fragments from one of our solar system’s so-called “lost” planets. … Dr. Gillet’s colleague Farhang Nabiei made the discovery while taking high-resolution images of a meteorite that had landed …about a decade ago. The space rock is classified as ureilite, a type of rare meteorite that has embedded within it several different types of minerals. And inside this one, they found diamonds. The nano-sized gems were …far from crystal clear. They were riddled with tiny imperfections, called inclusions, made of chromite, phosphate and iron-nickel sulfides. …“What for a jeweler is an imperfection becomes for me something that is very useful because it tells me about the history of the diamond,” said Dr. Gillet. “It has a chemistry which has no equivalent in the solar system today, in terms of planets,” he said. …because the chemistry of the inclusions did not match what is known on planets in today’s solar system, they think the diamonds came from a protoplanet that existed between 4.54 and 4.57 billion years ago…. https://www.nytimes.com/2018/04/18/science/diamonds-meteorite-lost-planet.html
2018-04-05. History of Mars’s Water, Seen Through the Lens of Gale Crater. By Ramin Skibba, AGU-Eos. Excerpt: Past research indicates that the Red Planet may have been a very different world more than 3 billion years ago, with warmer weather, flowing rivers, lakes, and possibly even oceans of liquid water. These conditions would have been much more hospitable to nascent life-forms, if they existed. However, recent research is uncovering a different story. “There have been two competing viewpoints about the Martian climate at this time: the traditional warm-and-wet view and the view that Mars was always cold and icy,” explained Jeffrey Andrews-Hanna, a Mars-focused planetary scientist at the University of Arizona. Now, enter a third scenario: Billions of years ago, “Mars never really experienced a temperate Earth-like climate,” Andrews-Hanna added. Instead, a body of recent evidence points to an arid early Mars with pockets of wet patches…. https://eos.org/articles/history-of-marss-water-seen-through-the-lens-of-gale-crater
2018-03-28. Surprising meteorite discovery points to early solar system chaos. By Paul VoosenMar, Science. Excerpt: The stately solar system of today was in turmoil in its first several million years, theorists believe, with giant planets sowing chaos as they strayed far from their current orbits. But corroborating evidence has been thin—until now. Scientists have found a new window into the early dynamics: a curious chemical divide in the dozens of species of meteorites. …in work presented last week at the Lunar and Planetary Science Conference here, a group of German geochemists …tested 32 meteorites representing nearly all known types and found that “any meteorite you take, it belongs to either one of these groups,” says Thorsten Kleine, a geochemist at the University of Münster in Germany who led the work. Those divergent chemistries imply distinct origin stories for asteroids, the parent bodies of most meteorites. One group formed from grist that began near the current location of the asteroid belt. The others coalesced much farther out, beyond a proto-Jupiter, near where Saturn orbits today. Only later, pushed and pulled by the wandering giant planets, did these immigrant asteroids find their home in today’s asteroid belt…. http://www.sciencemag.org/news/2018/03/surprising-meteorite-discovery-points-early-solar-system-chaos
2018-03-19. Mars’ oceans formed early, possibly aided by massive volcanic eruptions. By Robert Sanders, UC Berkeley News. Excerpt: A new scenario seeking to explain how Mars’ putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million years earlier and were not as deep as once thought. …The proposal by UC Berkeley geophysicists links the existence of oceans early in Mars history to the rise of the solar system’s largest volcanic system, Tharsis, and highlights the key role played by global warming in allowing liquid water to exist on Mars. “Volcanoes may be important in creating the conditions for Mars to be wet,” said Michael Manga, a UC Berkeley professor of earth and planetary science and senior author of a paper appearing in Nature this week and posted online March 19. Those claiming that Mars never had oceans of liquid water often point to the fact that estimates of the size of the oceans don’t jibe with estimates of how much water could be hidden today as permafrost underground and how much could have escaped into space. …The new model proposes that the oceans formed before or at the same time as Mars’ largest volcanic feature, Tharsis, instead of after Tharsis formed 3.7 billion years ago…. http://news.berkeley.edu/2018/03/19/mars-oceans-formed-early-possibly-aided-by-massive-volcanic-eruptions/
2018-03-09. Jupiter’s chaotic storms have roots deep beneath its surface. By Paul Voosen, Science. xcerpt: The gaseous veil of Jupiter’s surface has long cast a pall over scientists’ quest to understand the giant planet’s depths. In particular, researchers have debated whether the bands of east-west winds …extend deeper into the planet, or are merely superficial. Now, a series of papers from NASA’s Juno spacecraft, published today in Nature, has revealed that the roots of Jupiter’s winds indeed run deep. …Juno’s scientists discovered an asymmetry in Jupiter’s north-south gravitational field that reflected shifting masses driven by rising winds from 3000 kilometers deep within the planet. These flows of hydrogen and helium, the team shows, are driven up by energy lost from the planet’s deeper interior, which rotates like a solid because of crushing high pressures…. http://www.sciencemag.org/news/2018/03/jupiter-s-chaotic-storms-have-roots-deep-beneath-its-surface. See also Scientific American article: https://www.scientificamerican.com/article/juno-peers-deep-into-jupiters-abyss-to-reveal-weird-winds/
2018-02-02. India plans to land near moon’s south pole. By Pallava Bagla, Science. Summary: Sometime this summer, an Indian spacecraft orbiting over the moon’s far side will release a lander. The craft will ease to a soft landing just after lunar sunrise on an ancient, table-flat plain about 600 kilometers from the south pole. There, it will unleash a rover into territory never before explored at the surface. That’s the ambitious vision for India’s second voyage to the moon in a decade, due to launch in the coming weeks. If Chandrayaan-2 is successful, it will pave the way for even more ambitious Indian missions, such as landings on Mars and an asteroid, as well as a Venus probe. Lunar scientists have much at stake, too. Chandrayaan-2 will collect data on the moon’s thin envelope of plasma, as well as isotopes such as helium-3, a potential fuel for future fusion energy reactors. And it will follow up on a stunning discovery by India’s first lunar foray, which found water molecules on the moon in 2009…. http://science.sciencemag.org/content/359/6375/503
2018-01-12. Exposed subsurface ice sheets in the Martian mid-latitudes. By Colin M. Dundas et al, Science. Abstract: Thick deposits cover broad regions of the Martian mid-latitudes with a smooth mantle; erosion in these regions creates scarps that expose the internal structure of the mantle. We investigated eight of these locations and found that they expose deposits of water ice that can be >100 meters thick, extending downward from depths as shallow as 1 to 2 meters below the surface. The scarps are actively retreating because of sublimation of the exposed water ice. The ice deposits likely originated as snowfall during Mars’ high-obliquity periods and have now compacted into massive, fractured, and layered ice. We expect the vertical structure of Martian ice-rich deposits to preserve a record of ice deposition and past climate…. http://science.sciencemag.org/content/359/6372/199
2017-12-11. Four Planetary Landscapes That Scientists Can’t Explain. By JoAnna Wendel, AGU/Eos. Excerpt: These are just a handful of the hundreds of mysterious features across our solar neighborhood that beg to be studied closer. [see photos & info about:] “Brainy Mars”, “Willy Wonka and the Taffy Factory” [on Mars], “Carolina Bays” [Earth], “Bright Streaks” [on Saturn’s moon Dione]… https://eos.org/articles/four-planetary-landscapes-that-scientists-cant-explain
2017-11-20. Recurring Martian Streaks: Flowing Sand, Not Water? By Jet Propulsion Laboratory News. Excerpt: Fast Facts: › Seasonal dark streaks on Mars have been described as possible signs of flowing water; a new study shows they are a better fit to dry flow processes. › The steepness of more than 150 of these features was assessed with a telescopic camera on a NASA Mars orbiter. › The findings add to evidence that these environments may be too dry for microbes to thrive, despite the presence of water in hydrated salts. › How seasonal warming triggers these streaks is still a puzzle, and water may be involved…. https://www.jpl.nasa.gov/news/news.php?feature=7005
2017-10-26. Astronomers Spot First-Ever Space Rock from Another Star. By Lee Billings, Scientific American. Excerpt: For the first time ever, an asteroid or comet from another star has been caught hurtling through our solar system, astronomers announced late Thursday. Provisionally designated A/2017 U1, the object appears to be less than a half-kilometer in diameter and is traveling at just over 40 kilometers per second—faster than humanity’s speediest outbound space probes. Because this is the first object of its type to be found, there are as yet no official rules for naming it, and its discoverers have balked at suggesting anything besides “Interstellar.” Whatever one might call it, though, it is presently racing away from the sun and has sparked a stampede of astronomers rushing to observe it before it fades entirely from view in the darkness of interstellar space. “All we can say right now is this was something that was tossed out of another star system,” says Karen Meech, an astronomer at the University of Hawaii. Meech is helping coordinate a global observation campaign, which presently includes nights on large telescopes in Chile and Hawaii, as well as five orbits of the Hubble Space Telescope. “Everyone is trying to get time to look at this thing on big telescopes right now, urgently, within the next few days,” she explains. …Based on these analyses, A/2017 U1 came from the direction of the constellation Lyra, swooping in from high above the ecliptic plane in which the sun’s planets orbit at a breathtaking 25 kilometers per second. According to calculations by Micheli, that trajectory placed it 25 times farther out than Pluto in the year 1837, and it crossed the orbit of Neptune in November of 2012 on its sunward plunge. Pulled by our star’s gravity, on Sept. 9 A/2017 U1 approached within 40 million kilometers of the sun—well within the orbit of Mercury—before being flung back up and out of the ecliptic plane in the direction of the constellation Pegasus at nearly 44 kilometers per second. On Oct 14 it passed less than 25 million kilometers from Earth—about 60 times the Earth-moon distance. Astronomers could not see it, then, however, because its trajectory took it too close to the sun as seen from our planet’s skies…. https://www.scientificamerican.com/article/astronomers-spot-first-ever-space-rock-from-another-star/Update 11/9/2017: A/2017 U1 now has a newly approved IAU designation of 1I/’Oumuamua’ (1I/2017 U1).There’s a Wikipedia entry also: https://en.wikipedia.org/wiki/1I/%27OumuamuaArticle in Nature: https://www.nature.com/news/astronomers-race-to-learn-from-first-interstellar-asteroid-ever-seen-1.22925
2017-09-14. Cassini’s “Grand Finale” Will Be a Blaze of Glory. By Lee Billings, Scientific American. Excerpt: The Cassini orbiter will burn out, but its legacy won’t fade away. …For NASA’s Cassini orbiter—its fuel dwindling after 13 years exploring Saturn, along with the planet’s sprawling rings and dozens of icy moons—the end will come Friday at 7:55 A.M. Eastern time. That’s when mission planners project radio communications will be lost with the two-ton, bus-size spacecraft as it plunges into the giant planet’s turbulent atmosphere at more than 122,000 kilometers per hour. …“We are concluding the longest, deepest, most comprehensive scientific exploration of a remote planetary system ever undertaken, a system so alien it might as well have been orbiting another star in another galaxy,” says Carolyn Porco, the planetary scientist who leads Cassini’s imaging team. “And we have been profoundly successful.”… https://www.scientificamerican.com/article/cassinis-ldquo-grand-finale-rdquo-will-be-a-blaze-of-glory/ See also The Cassini spacecraft crashed into Saturn, ending a successful 20-year mission by Sarah Kaplan and Cassini Vanishes Into Saturn, Its Mission Celebrated and Mourned, by Kenneth Chang
2017-08-08. Chasing Shadows for a Glimpse of a Tiny World Beyond Pluto. By Kenneth Chang, The New York Times. Excerpt: This summer, scientists crisscrossed two oceans, braved wind and cold and deployed two dozen telescopes — all for five blinks of starlight that lasted a second or less. For the team working with NASA’s New Horizons spacecraft, which made a spectacular flyby of Pluto two years ago, those smidgens of data provide intriguing hints about the spacecraft’s next destination, a distant frozen world that is believed to be a pristine, undisturbed fragment from the earliest days of the solar system. New Horizons will fly past it on Jan. 1, 2019…. https://www.nytimes.com/2017/08/08/science/new-horizons-nasa-pluto-mu69-occultations.html
2017-08-01. Maria Mitchell’s Birthday. By Writer’s Almanac. Excerpt: Today is the birthday of Maria Mitchell …, the first acknowledged female astronomer, born in 1818 on the island of Nantucket in Massachusetts. …Maria Mitchell’s Quaker parents believed that girls should have the same access to education and the same chance to aspire to high goals as boys, and they raised all 10 of their children as equals. Maria’s early interest in science and the stars came from her father, a dedicated amateur astronomer who shared with all his children what he saw as physical evidence of God in the natural world, although Maria was the only child interested enough to learn the mathematics of astronomy. …By age 12, Maria was assisting her father with his astronomical observations and data, and just five years later opened and ran her own school for girls, training them in the sciences and math. In 1838, she became the librarian of the Nantucket Atheneum and began spending her evenings in an observatory her father had built atop the town’s bank. On October 1, 1848, a crisp, clear autumn evening, Maria focused her father’s telescope on a distant star. The light was faint and blurry, and Maria suddenly realized she was looking not at a star, but a comet; she recorded its coordinates, and when she saw the next night that the fuzzy light had moved, she was sure. Maria shared her discovery with her father, who wrote to the Harvard Observatory, who in turn passed her name on to the king of Denmark, who had pledged a gold medal to the first person to discover a comet so distant that it could only be seen through a telescope. Maria was awarded the medal the following year, and the comet became known as “Miss Mitchell’s Comet.” … https://www.nwhm.org/education-resources/biography/biographies/maria-mitchell-bio/
2017-07-28. Could a Newfound Molecule on Titan Be a Building Block for Life? By JoAnna Wendel, Earth & Space Science News Eos/AGU. Excerpt: The discovery of vinyl cyanide in the atmosphere of Saturn’s moon Titan has huge implications for life—but not as we know it. In the game of habitability, only a small fraction of celestial bodies in our solar system competes for the title “most compelling.” There’s Saturn’s moon Enceladus with its watery jets and internal ocean, Jupiter’s moon Europa with another internal ocean, and even our rocky neighbor Mars with its icy poles and occasional water flows. But Saturn’s largest moon, Titan, hiding under a haze of smog, just upped the ante. Researchers found a molecule called vinyl cyanide (C2H3CN) in Titan’s atmosphere. A collection of these molecules, should they rain down into Titan’s methane lakes, could link up to form membranous structures like the squishy walls of our cells, they say. “Detecting this molecule in the atmosphere suggests that there should be a bunch of it available in [Titan’s] lakes,” said Maureen Palmer, a researcher at NASA’s Goddard Space Flight Center in Greenbelt, Md., and lead author on a new paper published today in Science Advances. Moreover, because this molecule exists in the atmosphere, “maybe there’s a higher chance of these membranes actually forming” in Titan’s polar lakes and seas…. https://eos.org/articles/could-a-newfound-molecule-on-titan-be-a-building-block-for-life
2017-07-19. Saturn Unveiled: Ten Notable Findings from Cassini-Huygens. By JoAnna Wendel, Eos/AGU. Excerpt: The Cassini-Huygens mission launched on 15 October 1997, carrying 12 scientific instruments and a 2-meter-wide saucer-shaped probe called Huygens to land on Saturn’s hazy moon Titan. …Since its arrival at Saturn in 2004, Cassini has traveled more than 3 billion kilometers in more than 200 orbits around Saturn. It has flown by Titan more than 100 times and the icy ocean moon Enceladus 23 times. And on 14 January 2005, when the Huygens probe touched down on Titan, the mission became the first to successfully drop a lander on an outer solar system moon. …. 1. Cassini Revealed Enceladus’s Potentially Habitable Internal Ocean…. 2. Huygens Showed Us Titan, a Possibly Primordial Earthlike World…. 3. Cassini Changed How We Think of “Habitability”…. 4. Cassini Found Enceladus Ocean Material in the E Ring…. 5. Cassini Unlocked Mysteries of Saturn’s Hexagon…. 6. Cassini Showed Us One of Saturn’s Huge, Infrequent Storms…. 7. …And That Storm Helped Cassini Detect Atmospheric Water…. 8. Cassini Dazzled Scientists with Saturn’s Color-Changing Atmosphere…. 9. Cassini Spied Saturn’s Rings Acting Like a Seismometer…. 10. Cassini Showed Us Saturn’s Other Dynamic Moons…. https://eos.org/features/saturn-unveiled-ten-notable-findings-from-cassini-huygens
2017-07-12. Jupiter’s Great Red Spot Gets Its Close-Up. By Kenneth Chang, The New York Times. Excerpt: NASA’s Juno spacecraft has been making repeated swoops just above the cloud tops of Jupiter. During the latest flyby, on Monday, the spacecraft passed about 5,600 miles over the Great Red Spot, a 10,000-mile-wide storm that has swirled for at least 350 years. NASA posted images from the flyby on the web on Wednesday. …“The more we zoom into the Great Red Spot, the more turbulent it seems to be,” said James O’Donoghue, another scientist at NASA Goddard. “In some of the processed images we can clearly see anticlockwise rotating cells within the giant storm itself — storms within storms.”…. https://www.nytimes.com/2017/07/12/science/jupiter-great-red-spot-nasa-juno.html
2017-05-25. NASA’s Jupiter Mission Reveals the ‘Brand-New and Unexpected’. By Kenneth Chang, The New York Times. Excerpt: The top and bottom of Jupiter are pockmarked with a chaotic mélange of swirls that are immense storms hundreds of miles across. The planet’s interior core appears bigger than expected, and swirling electric currents are generating surprisingly strong magnetic fields. Auroral lights shining in Jupiter’s polar regions seem to operate in a reverse way to those on Earth. And a belt of ammonia may be rising around the planet’s equator. Those are some early findings of scientists working on NASA’s Juno mission, an orbiter that arrived at Jupiter last July. Juno takes 53 days to loop around Jupiter in a highly elliptical orbit, but most of the data gathering occurs in two-hour bursts when it accelerates to 129,000 miles an hour and dives to within about 2,600 miles of the cloud tops. The spacecraft’s instruments peer far beneath, giving glimpses of the inside of the planet, the solar system’s largest. …Planetary scientists had wondered whether Jupiter would have a giant hexagonal pattern like that spotted on Saturn by NASA’s Cassini spacecraft. …In contrast to the chaotic weather patterns at Jupiter’s poles, a stable hexagonal pattern covers Saturn’s north pole. … https://www.nytimes.com/2017/05/25/science/nasa-juno-spacecraft-jupiter-storms.html
2017-05-10. Waves of lava seen in Io’s largest volcanic crater. By Robert Sanders, Media relations, UC Berkeley News. Excerpt: Taking advantage of a rare orbital alignment between two of Jupiter’s moons, Io and Europa, researchers have obtained an exceptionally detailed map of the largest lava lake on Io, the most volcanically active body in the solar system. …Overturning lava is a popular explanation for the periodic brightening and dimming of the hot spot, called Loki Patera after the Norse god. (A patera is a bowl-shaped volcanic crater.) The most active volcanic site on Io, which itself is the most volcanically active body in the solar system, Loki Patera is about 200 kilometers (127 miles) across. The hot region of the patera has a surface area of 21,500 square kilometers, larger than Lake Ontario. Earthbound astronomers first noticed Io’s changing brightness in the 1970s, but only when the Voyager 1 and 2 spacecraft flew by in 1979 did it become clear that this was because of volcanic eruptions on the surface. Despite highly detailed images from NASA’s Galileo mission in the late 1990s and early 2000s, astronomers continue to debate whether the brightenings at Loki Patera – which occur every 400 to 600 days – are due to overturning lava in a massive lava lake, or periodic eruptions that spread lava flows over a large area…. http://news.berkeley.edu/2017/05/10/waves-of-lava-seen-in-ios-largest-volcanic-crater/
2017-04-13. Food for microbes abundant on Enceladus. By Paul Voosen, Science. 2017-05-25. NASA’s Jupiter Mission Reveals the ‘Brand-New and Unexpected’. By Kenneth Chang, The New York Times. Excerpt: In 2005, NASA’s Cassini spacecraft spied jets of water ice and vapor erupting into space from fissures on Enceladus, evidence of a salty ocean beneath the saturnian moon’s placid icy surface. Now, it turns out that the jets contain hydrogen gas, a sign of ongoing reactions on the floor of that alien sea. Because such chemistry provides energy for microbial life on Earth, the discovery makes Enceladus the top candidate for hosting life elsewhere in the solar system—besting even Jupiter’s Europa, another icy moon with an ocean. “We didn’t see microbes,” says Hunter Waite, a planetary scientist at the Southwest Research Institute in San Antonio, Texas, and the lead author of a study published this week in Science. “But we saw their food.”… http://www.sciencemag.org/news/2017/04/food-microbes-abundant-enceladus
2017-03-24. Lunar Lava Tubes Could Offer Future Moon Explorers a Safe Haven. By JoAnna Wendel, Earth & Space Science News (AGU). Excerpt: Scientists find evidence that a 50-meter-deep pit on the Moon’s surface could be a skylight opening to an intact lava tube tens of kilometers long. Lunar colonization isn’t mere science fiction anymore. Billionaires plan to send tourists on once-in-a-lifetime trips, and politicians say that they hope to colonize the Moon in the next few decades. There may even be ways for human colonists to harvest water from ice that may be permanently shadowed in certain caves. But where could a human colony actually live? The Moon has no atmosphere or magnetic field to shield it from solar radiation and micrometeorites that constantly rain onto its surface. That’s no environment for our squishy, earthling bodies. Scientists studying the Moon’s surface may have found the answer: shelter humans in lunar lava tubes. The Moon is covered in huge swaths of ancient basaltic lava flows. Earth’s volcanoes can also erupt similar flows, with basalt sometimes running as molten rivers. In these rivers, the outside cools faster than the inside, creating a hard shell. The remaining lava pours out, leaving a hollow space behind…. https://eos.org/articles/lunar-lava-tubes-could-offer-future-moon-explorers-a-safe-haven
2017-03-10. New Images of Pan, Saturn’s Walnut Moon, in Unprecedented Detail. By JoAnna Wendel, Earth & Space Science News, EoS (AGU). Excerpt: It’s a flying saucer! No, a celestial empanada! Or space ravioli? Nope—the weird raw images dropped by NASA’s Jet Propulsion Laboratory this week feature Saturn’s tiny moon Pan and its equatorial fringe in unprecedented detail. The Cassini spacecraft, which has been orbiting Saturn since 2004, will crash into Saturn later this year. But its final descent brings the spacecraft closer than ever before to Saturn’s rings and offers scientists a wealth of new research opportunities.This is because the spacecraft has entered its “ring grazing orbits,” Carolyn Porco, leader of the imaging science team for Cassini and current visiting scholar at the University of California in Berkeley, told Eos. …This close orbit allows the spacecraft to take close-up pictures of moons like Pan, which orbits Saturn at a distance of 134,000 kilometers. The new images of the 35-kilometer-wide moon feature a resolution as fine as 150 meters….Scientists have known about Pan’s tutu-shaped waistline for a long time. Ten years ago, Porco and her team wrote two papers describing how the bulge could have formed. From computer models, the researchers suspect that as the moon coalesced, material from Saturn’s rings fell onto the tiny moon’s equator and built up its disklike silhouette…. https://eos.org/articles/new-images-of-pan-saturns-walnut-moon-in-unprecedented-detail
2017-02-17. Building blocks of life found on dwarf planet Ceres. By CBC News, Thomson Reuters. Excerpt: A NASA spacecraft has detected carbon-based materials, similar to what may have been the building blocks for life on Earth, on the Texas-sized dwarf planet Ceres that orbits between Mars and Jupiter in the main asteroid belt, scientists said on Thursday. The finding puts Ceres, a rock-and-ice world about 950 kilometres in diameter, on a growing list of places in the solar system of interest to scientists looking for life beyond Earth. The list includes Mars and several ocean-bearing moons of Jupiter and Saturn. The discovery, published in the journal Science, was made by a team of researchers using NASA’s Dawn spacecraft, which has been orbiting Ceres for nearly two years. “I think these organic molecules are a long way from microbial life,” Dawn lead scientist Christopher Russell of the University of California Los Angeles (UCLA) wrote in an email to Reuters. “However, this discovery tells us that we need to explore Ceres further. …The discovery indicates that the starting material in the solar system contained the essential elements, or the building blocks, for life,” Russell said…. http://www.smithsonianmag.com/smart-news/organic-material-found-chilly-ceres-180962227/
2017-01-23. Ancient Bits of Rock Help Solve an Asteroid Mystery. By Kenneth Chang, The New York Times. Excerpt: one might think that meteorites that fall on Earth ought to be just like the asteroids that pass through Earth’s neighborhood. “That’s what everybody would have expected,” said Philipp R. Heck, the curator in charge for the meteorite and physical geology collections at the Field Museum of Natural History in Chicago. Planetary scientists were surprised almost a decade ago when they discovered that the most plentiful types of meteorites they had collected and studied on Earth were actually not common in space. In a paper published Monday by the journal Nature Astronomy, an international team of researchers led by Dr. Heck says it has uncovered part of the explanation. Mineralogical evidence in some meteorites had already pointed to a cataclysmic collision in the asteroid belt about 466 million years ago — long before dinosaurs, when multicellular animals were still fairly new. (Dr. Heck estimated that any skywatchers back then would have seen about 100 times as many shooting stars as crisscross the night sky today.). …The findings fits in with the new understanding that a mix of meteorites is determined more by the history of collisions in the asteroid belt rather than by the mix of asteroids whose orbits around the sun are close to Earth’s…. https://www.nytimes.com/2017/01/23/science/ancient-bits-of-rock-help-solve-an-asteroid-mystery.html
2016-12-12. ALMA Finds Compelling Evidence for Pair of Infant Planets around Young Star. By National Radio Astronomy Observatory. Excerpt: Astronomers now know that our galaxy is teeming with planets, from rocky worlds roughly the size of Earth to gas giants bigger than Jupiter. Nearly every one of these exoplanets has been discovered in orbit around a mature star with a fully evolved planetary system. New observations with the Atacama Large Millimeter/submillimeter Array (ALMA) contain compelling evidence that two newborn planets, each about the size of Saturn, are in orbit around a young star known as HD 163296. These planets, which are not yet fully formed, revealed themselves by the dual imprint they left in both the dust and the gas portions of the star’s protoplanetary disk. [see image https://public.nrao.edu/wp-content/uploads/2016/12/imagespr2016cbnrao16cb25nrao16cb25a_nrao-1170×600.jpg]… https://public.nrao.edu/news/2016-alma-planets-disk/
2016-11-25. An Ice Sheet the Size of New Mexico Hidden in Martian Crater. By Kenneth Chang, The New York Times. Excerpt: An ice sheet with more water than Lake Superior may slake the thirst of future astronauts living on Mars. Using radar soundings from NASA’s Mars Reconnaissance Orbiter spacecraft, scientists probed what lies in Utopia Planitia, a 2,000-mile-wide basin within an ancient impact crater. For decades, the region looked intriguing because of polygonal cracking and scalloped depressions in the landscape. In places on Earth like the Canadian Arctic, patterns like these arise from ice beneath the surface. The ground cracks as ice underneath expands and contracts with the changing temperatures; the scallops, as if carved by an ice cream scoop, are places where the surface sinks as the ice melts. “We’d say, ‘It looks like there’s ground ice there,’” Cassie Stuurman, a graduate student at the University of Texas at Austin, said about Utopia Planitia. “What we haven’t known is how much is there.”n …Ms. Stuurman, the lead author of an article in the journal Geophysical Research Letters that described the findings, said the radar reflections revealed that the ice sheet, ranging in thickness from 260 to 560 feet, covered an area larger than New Mexico. …Water ice is plentiful at the Martian poles, but Utopia Planitia might be a more attractive landing site for future astronauts, because it is in the more temperate mid-northern latitudes…. http://www.nytimes.com/2016/11/25/science/mars-ice-sheet.html
2016-09-26. NASA’s Hubble Spots Possible Water Plumes Erupting on Jupiter’s Moon Europa. NASA RELEASE 16-096. Excerpt: Astronomers using NASA’s Hubble Space Telescope have imaged what may be water vapor plumes erupting off the surface of Jupiter’s moon Europa. …The observation increases the possibility that missions to Europa may be able to sample Europa’s ocean without having to drill through miles of ice. “Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” said Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.” The plumes are estimated to rise about 125 miles (200 kilometers) before, presumably, raining material back down onto Europa’s surface. Europa has a huge global ocean containing twice as much water as Earth’s oceans, but it is protected by a layer of extremely cold and hard ice of unknown thickness. …If confirmed, Europa would be the second moon in the solar system known to have water vapor plumes. In 2005, NASA’s Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn’s moon Enceladus. Scientists may use the infrared vision of NASA’s James Webb Space Telescope, which is scheduled to launch in 2018, to confirm venting or plume activity on Europa. NASA also is formulating a mission to Europa with a payload that could confirm the presence of plumes and study them from close range during multiple flybys…. http://www.nasa.gov/press-release/nasa-s-hubble-spots-possible-water-plumes-erupting-on-jupiters-moon-europa
2016-08-17. Six Things Dwarf Planets Have Taught Us About the Solar System. By By JoAnna Wendel Earth & Space News EoS (AGU). Excerpt: 1. Dwarf Planets Are as Complex as Regular Planets. …2. Dwarf Planets Reveal Neptune’s Orbital Origins. …3. Dwarf Planets Give Us a Peek into the Early Solar System. …4. Dwarf Planet Candidates Helped Scientists “Find” Planet 9. …5. Ceres (We Hope) Will Help Us Understand Icy Ocean Moons. …6. Dwarf Planets Are Prolific…. https://eos.org/articles/six-things-dwarf-planets-have-taught-us-about-the-solar-system
2016-07-28. Forbidden planets: Understanding alien worlds once thought impossible. By Daniel Clery, Science. Excerpt: …The planet hunt accelerated with the launch of NASA’s Kepler spacecraft in 2009, and the 2500 worlds it has discovered added statistical heft to the study of exoplanets—and yet more confusion. Kepler found that the most common type of planet in the galaxy is something between the size of Earth and Neptune—a “super-Earth,” which has no parallel in our solar system and was thought to be almost impossible to make. …Other planetary systems looked nothing like our orderly solar system, challenging the well-worn theories that had been developed to explain it. …The traditional model of how stars and their planets form dates back to the 18th century, when scientists proposed that a slowly rotating cloud of dust and gas could collapse under its own gravity. …This scenario naturally produces a planetary system just like our own: small, rocky planets with thin atmospheres close to the star, a Jupiter-like gas giant just beyond the snowline, and the other giants getting progressively smaller at greater distances because they move more slowly through their orbits and take longer to hoover up material. …But the discovery of hot Jupiters suggested something was seriously amiss with the theory. …Theorists have come up with two possible mechanisms for shuffling the planetary deck. The first, known as migration, requires there to be plenty of material left in the disk after the giant planet has formed. …If the past is anything to go by, modelers will have to keep on their toes. “Nature is smarter than our theories,” Rafikov says. http://www.sciencemag.org/news/2016/07/forbidden-planets-understanding-alien-worlds-once-thought-impossible
2016-06-28. NASA’s Juno Spacecraft Will Soon Be in Jupiter’s Grip. By Kenneth Chang, New York Times. Excerpt: After traveling for five years and nearly 1.8 billion miles, NASA’s Juno spacecraft will announce its arrival at Jupiter with the simplest of radio signals: a three-second beep. …Juno’s mission is to explore the enigmas beneath the cloud tops of Jupiter. How far down does the Big Red Spot storm that has swirled for centuries extend? What is inside the solar system’s largest planet? …“One of the primary goals of Juno is to learn the recipe for solar systems,” said Scott Bolton, a scientist at the Southwest Research Institute in San Antonio who is the principal investigator for the $1.1 billion mission. “How do you make the solar system? How do you make the planets in our solar system?”… http://www.nytimes.com/2016/06/28/science/nasa-jupiter-juno.html See also video http://www.nytimes.com/video/science/100000004498333/juno-piercing-jupiters-clouds.html
2016-05-19. Seeking Pluto’s Frigid Heart. By The New York Times. Excerpt: Set foot on [Pluto] an alien world, three billion miles from the warmth of the sun. Download the NYT VR [virtual reality] app for Android or iPhone. [Different views are seen by moving the smart phone to different viewing angles. Or use cardboard viewer for effect]… http://www.nytimes.com/interactive/2016/05/19/science/space/seeking-plutos-frigid-heart-nytvr.html
2016-05-19. Tsunamis Splashed Ancient Mars. By Shannon Hall, EoS-Earth & Space Science News (AGU). Excerpt: Massive meteorites likely slammed into a Martian ocean billions of years ago, unleashing tsunami waves up to 120 meters tall, a close study of a region of the Red Planet’s terrain has found…. https://eos.org/articles/tsunamis-splashed-ancient-mars
2016-01-20. Evidence suggests huge ninth planet exists past Pluto at solar system’s edge. By Ian Sample, The Guardian. Excerpt: Astronomers investigating the odd alignment of rocks beyond Pluto have concluded that an undetected icy planet four times the size of Earth must exist. …If the researchers have their sums right, the mysterious new world is 10 times more massive than Earth and up to four times the size. Nicknamed Planet Nine, it moves on an extremely elongated orbit, and takes a staggering 10,000 to 20,000 years to swing once around the sun. …Scientists at the California Institute of Technology (Caltech) calculate that the closest it comes to the sun is 15 times the distance to Pluto. It then heads into uncharted territory, 75 times further out than Pluto, or about 93 billion miles from the sun. A ray of light would take a week to get there. …Chris Lintott… said …“One very interesting thing is that the planet is predicted to be between Earth and Neptune in mass. We see lots of planets this size in our surveys of planets elsewhere in the galaxy, and it’s been something of a mystery as to why our solar system doesn’t have its own version of this very common planet type,” he added….. http://www.theguardian.com/science/2016/jan/20/ninth-planet-solar-system-edge-discovery-pluto See also New York Times article.
2015-12-04 New Horizons Returns First of the Best Images of Pluto [NASA Feature]
Latest New Horizons Science Photos – http://pluto.jhuapl.edu/Multimedia/Science-Photos/index.php — Images: http://pluto.jhuapl.edu/Multimedia/Science-Photos/pics/Very-Best-View-of-Pluto.png
nasa.gov page for New Horizons – https://www.nasa.gov/mission_pages/newhorizons/main/index.html
2015-11-23. Mars to lose its largest moon, but gain a ring. By Robert Sanders, UC Berkeley News. Excerpt: Mars’ largest moon, Phobos, is slowly falling toward the planet, but rather than smash into the surface, it likely will be shredded and the pieces strewn about the planet in a ring like the rings encircling Saturn, Jupiter, Uranus and Neptune …in 10-20 million years… that will persist for anywhere from one million to 100 million years, according to two young earth scientists at the University of California, Berkeley. In a paper appearing online this week in Nature Geoscience, UC Berkeley postdoctoral fellow Benjamin Black and graduate student Tushar Mittal estimate the cohesiveness of Phobos and conclude that it is insufficient to resist the tidal forces that will pull it apart when it gets closer to Mars. Just as earth’s moon pulls on our planet in different directions, raising tides in the oceans, for example, so too Mars tugs differently on different parts of Phobos. As Phobos gets closer to the planet, the tugs are enough to actually pull the moon apart, the scientists say. This is because Phobos is highly fractured, with lots of pores and rubble. Dismembering it is analogous to pulling apart a granola bar, Black said, scattering crumbs and chunks everywhere. …Mittal said it’s not clear whether the dust and debris rings would be visible from earth, since dust does not reflect much sunlight, whereas ice in the rings of the outer planets makes them easily visible…. http://news.berkeley.edu/2015/11/23/mars-to-lose-its-largest-moon-but-gain-a-ring/
2015-11-12. The Dwarf Planet That Came in from the Cold—Maybe. By Ron Cowen, EoS, Earth & Space Science News, AGU. Excerpt: …The presence of ammonia-rich clay on much of the surface of Ceres suggests that this dwarf planet—the largest object in the asteroid belt—may have formed far out in the solar system, then wandered in…. https://eos.org/articles/the-dwarf-planet-that-came-in-from-the-cold-maybe
2015-11-09. Four Months after Pluto Flyby, NASA’s New Horizons Yields Wealth of Discovery. NASA Release 15-214. Excerpt: From possible ice volcanoes to twirling moons, NASA’s New Horizons science team is discussing more than 50 exciting discoveries about Pluto at this week’s 47th Annual Meeting of the American Astronomical Society’s Division for Planetary Sciences in National Harbor, Maryland. … New Horizons geologists combined images of Pluto’s surface to make 3-D maps that indicate two of Pluto’s most distinctive mountains could be cryovolcanoes — ice volcanoes that may have been active in the recent geological past. Pluto’s surface varies in age — from ancient, to intermediate, to relatively young –according to another new finding from New Horizons. …nearly every other moon in the solar system — including Earth’s moon — is in synchronous rotation, keeping one face toward the planet. This is not the case for Pluto’s small moons. Pluto’s small lunar satellites are spinning much faster, with Hydra — its most distant moon — rotating an unprecedented 89 times during a single lap around the planet. To determine the age of a surface area of the planet, scientists count crater impacts. … http://www.nasa.gov/press-release/four-months-after-pluto-flyby-nasa-s-new-horizons-yields-wealth-of-discovery See also Press Conference images.
2015-10-30. Cassini samples an alien ocean. By Carolyn Gramling, Science. Excerpt: NASA’s Cassini spacecraft has just sent back the first pictures from its deep plunge toward the surface of icy Enceladus, a flyby that took it through one of the moon’s geysers. …Since Cassini began its flybys of Saturn and its moons in 2005, scientists have learned that beneath the layer of ice is a global ocean about 10 kilometers thick that may harbor life and probably contains hydrothermal vents. They have spotted more than 100 huge geysers of ice particles, water vapor, and organic molecules spewing from fractures in the ice covering Enceladus’s south polar region. These plumes shoot the contents of the moon’s subglacial ocean hundreds of kilometers high, in eruptions that may resemble curtains rather than columns. This week, the spacecraft made its deepest dive into one such plume—just 49 kilometers above the moon’s surface—to sample its contents…. http://news.sciencemag.org/space/2015/10/cassini-samples-alien-ocean See also: 2015 Mar 11 Cassini News Spacecraft Data Suggest Saturn Moon’s Ocean May Harbor Hydrothermal Activity: “Hydrothermal activity occurs when seawater infiltrates and reacts with a rocky crust and emerges as a heated, mineral-laden solution, a natural occurrence in Earth’s oceans. According to two science papers, the results are the first clear indications an icy moon may have similar ongoing active processes. The first paper, published this week in the journal Nature, relates to microscopic grains of rock detected by Cassini…. An extensive, four-year analysis of data from the spacecraft, …led researchers to the conclusion the tiny grains most likely form when hot water containing dissolved minerals from the moon’s rocky interior travels upward, coming into contact with cooler water. Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius)….”
2015-10-16. The Pluto system: Initial results from its exploration by New Horizons. By S. A. Stern1, F. Bagenal, et al, Science. Abstract: The Pluto system was recently explored by NASA’s New Horizons spacecraft, making closest approach on 14 July 2015. Pluto’s surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto’s atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto’s diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto’s large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected. … http://www.sciencemag.org/content/350/6258/aad1815.full For latest images from New Horizons Mission to Pluto, see http://pluto.jhuapl.e.du/ New images will be received every week through the end of 2015 and several months of 2016.
2015-10-12. Enceladus’s subsurface ocean wraps the moon. By Steven K. Blau, Physics Today. Excerpt: The satellite’s response to torque applied by Saturn shows that its icy surface and silicate core are not attached. A decade ago the Cassini orbiter spotted gas and ice spewing from the south polar region of Saturn’s moon Enceladus. Subsequent investigations revealed that the ice is salty, a result indicating that the ice originated from a liquid ocean between Enceladus’s frozen surface and its silicate core. Now Peter Thomas (Cornell University) and his colleagues have analyzed more than seven years of Cassini surface observations and shown that the ocean is not localized at the polar region of Enceladus; rather, it is global…. http://scitation.aip.org/content/aip/magazine/physicstoday/news/10.1063/PT.5.7210
2015-09-28. Dark streaks on Mars are definitely wet, NASA says. By Eric Hand, Science. Excerpt: Beginning in 2011, scientists using the Mars Reconnaissance Orbiter (MRO)…found hundreds of streaks, about 5 meters wide, that appear seasonally on steep slopes…. They show up during the warm season, grow hundreds of meters long, and then fade as winter approaches. For many years, the team made the obvious interpretation: …today on Mars, water was flowing, or at least seeping out of the surface. Salts were expected to be present in the water, because they lower the freezing point of water by tens of degrees, and they also make the water less likely to evaporate in Mars’s barely-there atmosphere. …Now, they have found evidence for those salts, …the water could get to the surface streaks either from above, via deliquescence—the absorption of water vapor from the atmosphere—or from below, via an underground aquifer. See the related 5 August 2011 report, “Seasonal flows on warm Martian slopes.” http://news.sciencemag.org/space/2015/09/dark-streaks-mars-are-definitely-wet-nasa-says
2015-08-21. Saturn’s moon has a fluffy heart. By Nola Taylor Redd, Science. Excerpt: Saturn’s moon, Enceladus, may not have a heart of stone—at least, not completely. A new model suggests the satellite has a rubble-filled pile of boulders and ice at its core, rather than a more conventional solid stone center. This “fluffy core” could help solve the mystery of the moon’s underground ocean. A watery layer beneath Enceladus’s crust has long been suspected to exist because of the constant eruption of geysers at its southern pole. But scientists have said that any such ocean should have frozen over the lifetime of the Saturn system. Tidal heating that warms the insides of moons and planets in orbit would simply not be enough to keep this ocean in a liquid state if Enceladus had a solid core. …A heart of rubble would flex more easily with the tidal pull of Saturn, emitting enough heat to maintain a liquid layer…. http://news.sciencemag.org/space/2015/08/saturn-s-moon-has-fluffy-heart
2015 July 14. NASA’s Three-Billion-Mile Journey to Pluto Reaches Historic Encounter NASA Release 15-149. NASA’s New Horizons spacecraft is at Pluto. After a decade-long journey through our solar system, New Horizons made its closest approach to Pluto Tuesday, about 7,750 miles above the surface — roughly the same distance from New York to Mumbai, India – making it the first-ever space mission to explore a world so far from Earth. [photo taken on July 13, 2015 when the spacecraft was 476,000 miles (768,000 kilometers) from the surface. …the last and most detailed image sent to Earth before the spacecraft’s closest approach to Pluto on July 14.] http://www.nasa.gov/press-release/nasas-three-billion-mile-journey-to-pluto-reaches-historic-encounter – See also NASA Release 15-152, July 15, 2015: From Mountains to Moons: Multiple Discoveries from NASA’s New Horizons Pluto Mission – http://www.nasa.gov/press-release/from-mountains-to-moons-multiple-discoveries-from-nasa-s-new-horizons-pluto-mission 0 and NASA Release 15-154, July 17, 2015: NASA’s New Horizons Discovers Frozen Plains in the Heart of Pluto’s ‘Heart’ – http://www.nasa.gov/press-release/nasa-s-new-horizons-discovers-frozen-plains-in-the-heart-of-pluto-s-heart
2015-06-03. NASA’s Hubble Finds Pluto’s Moons Tumbling in Absolute Chaos. NASA Release 15-111. Excerpt: If you lived on one of Pluto’s moons, you might have a hard time determining when, or from which direction, the sun will rise each day. Comprehensive analysis of data from NASA’s Hubble Space Telescope shows that two of Pluto’s moons, Nix and Hydra, wobble unpredictably. “Hubble has provided a new view of Pluto and its moons revealing a cosmic dance with a chaotic rhythm,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate in Washington. …The moons wobble because they’re embedded in a gravitational field that shifts constantly. This shift is created by the double planet system of Pluto and Charon as they whirl about each other. Pluto and Charon are called a double planet because they share a common center of gravity located in the space between the bodies. Their variable gravitational field sends the smaller moons tumbling erratically. The effect is strengthened by the football-like, rather than spherical, shape of the moons…. http://www.nasa.gov/press-release/nasa-s-hubble-finds-pluto-s-moons-tumbling-in-absolute-chaos. See also New York Times article [http://www.nytimes.com/2015/06/04/science/space/pluto-moons-orbits-described-in-nature-article.html] with movie of the moons’ motion.
2015-03-12. Huge ocean confirmed underneath solar system’s largest moon. By Eric Hand, Science. Excerpt: The solar system’s largest moon, Ganymede, in orbit around Jupiter, harbors an underground ocean containing more water than all the oceans on Earth. …new observations by the Hubble Space Telescope, published online today in the Journal of Geophysical Research: Space Physics, remove any remaining doubt. Ganymede now joins Jupiter’s Europa and two moons of Saturn, Titan and Enceladus, as moons with subsurface oceans—and good places to look for life. …The Hubble study suggests that the ocean can be no deeper than 330 kilometers below the surface…. http://news.sciencemag.org/space/2015/03/huge-ocean-confirmed-underneath-solar-system-s-largest-moon.
2015-03-06. NASA Spacecraft Becomes First to Orbit a Dwarf Planet. NASA RELEASE 15-034. Excerpt: NASA’s Dawn spacecraft has become the first mission to achieve orbit around a dwarf planet. The spacecraft was approximately 38,000 miles (61,000 kilometers) from Ceres when it was captured by the dwarf planet’s gravity at about 4:39 a.m. PST (7:39 a.m. EST) Friday. …”Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet,” said Marc Rayman, Dawn chief engineer and mission director at JPL. “Now, after a journey of 3.1 billion miles (4.9 billion kilometers) and 7.5 years, Dawn calls Ceres, home.”…. http://www.nasa.gov/press/2015/march/nasa-spacecraft-becomes-first-to-orbit-a-dwarf-planet/#.VPy7UmZIfZE. See also New York Times photos.
2015-03-05. NASA Research Suggests Mars Once Had More Water than Earth’s Arctic Ocean. NASA RELEASE 15-032. Excerpt: NASA scientists have determined that a primitive ocean on Mars held more water than Earth’s Arctic Ocean and that the Red Planet has lost 87 percent of that water to space…. Scientists have been searching for answers to why this vast water supply left the surface. Details of the observations and computations appear in Thursday’s edition of Science magazine…. “With Mars losing that much water, the planet was very likely wet for a longer period of time than was previously thought, suggesting it might have been habitable for longer,” said Michael Mumma, a senior scientist at Goddard and the second author on the paper. http://www.nasa.gov/press/2015/march/nasa-research-suggests-mars-once-had-more-water-than-earth-s-arctic-ocean/. See also New York Times article Ancient Mars Had an Ocean, Scientists Say.
2015-01-22. Ten new Rosetta images that reveal comet 67P in all its glory. By Eric Hand, Science. Excerpt: In August 2014, the European Space Agency’s Rosetta spacecraft arrived at comet 67P/Churyumov-Gerasimenko. Once in orbit, it swooped as low as 10 kilometers to get unprecedented data from the comet (and to drop off its short-lived Philae lander). Today, Science is publishing a suite of new papers detailing some of the mission’s first findings, …. Active pits… Erosion from cliff faces… boulders on unstable slopes… jetting…fissure…comet vomit…windlike features…. http://news.sciencemag.org/space/2015/01/ten-new-rosetta-images-reveal-comet-67p-all-its-glory.
2014-12-10. Comet Data Clears Up Debate on Earth’s Water. By Kenneth Chang, The New York Times. Excerpt: One of the first scientific findings to emerge from close-up study of a comet has all but settled a question that planetary scientists have debated for decades. The new finding, from the European Space Agency’s mission to the little duck-shaped comet called 67P/Churyumov-Gerasimenko, appears to eliminate the possibility that the water in Earth’s oceans came from melted comets. Water vapor streaming off the comet contains a higher fraction of “heavy hydrogen” than the water on Earth does, scientists reported on Wednesday. “That now probably rules out” comets as the primary source of terrestrial water, said Kathrin Altwegg, a scientist at the University of Bern in Switzerland and the principal investigator for the Rosetta instrument that made the measurements. With comets unlikely, most astronomers now think Earth’s water came from asteroids. …The new findings, published in the journal Science, came after Rosetta arrived at Comet 67P in August, close enough for the instrument to begin detailed analysis of the molecules coming off the comet. …Earth may have been wet from almost the beginning…. http://www.nytimes.com/2014/12/11/science/rosetta-mission-data-rules-out-comets-as-a-source-for-earths-water.html. See also: 2014 Dec 11 Science article.
2014-12-08. NASA’s Curiosity Rover Finds Clues to How Water Helped Shape Martian Landscape. NASA RELEASE 14-326.
2014-11-12. Landing on Comet, a Mission Aims to Unlock Earth’s Mysteries. By Kenneth Chang, The New York Times.
2014-09-08. Scientists Find Evidence of ‘Diving’ Tectonic Plates on Jupiter’s Moon Europa. Excerpt: Scientists have found evidence of plate tectonics on Jupiter’s moon Europa. This indicates the first sign of this type of surface-shifting geological activity on a world other than Earth. …While examining Europa images taken by NASA’s Galileo orbiter in the early 2000s, planetary geologists Simon Kattenhorn, of the University of Idaho, Moscow, and Louise Prockter, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, discovered some unusual geological boundaries. …When Kattenhorn and Prockter rearranged the icy terrain in the images, they discovered about 7,700 square miles (about 20,000 square kilometers) of the surface were missing in the moon’s high northern latitudes. Further evidence suggested the missing terrain moved under a second surface plate — a scenario commonly seen on Earth at plate-tectonic boundaries. Kattenhorn and Prockter saw ice volcanoes on the overriding plate, possibly formed through melting and absorption of the slab as it dove below the surface, and a lack of mountains at the subduction zone, implying material was pushed into the interior rather than crumpled up as the two plates mashed against each other. The scientists believe the subducted area was absorbed into Europa’s ice shell, which may be up to 20 miles (about 30 kilometers) thick, rather than breaking through it into Europa’s underlying ocean. …Previous scientific findings point to the existence of a liquid water ocean located under the moon’s icy crust. This ocean covers Europa entirely and contains more liquid water than all of Earth’s oceans combined. …For more information about Europa and images of the plate tectonics, visit: http://solarsystem.nasa.gov/europa. Information is available online about the Galileo Mission at: http://www.jpl.nasa.gov/missions/galileo …. http://www.nasa.gov/press/2014/september/scientists-find-evidence-of-diving-tectonic-plates-on-jupiter-s-moon-europa/#.VA7BmUiyPZE. By NASA RELEASE 14-241.
2014-08-28. NASA’s Spitzer Telescope Witnesses Asteroid Smashup. Excerpt: NASA’s Spitzer Space Telescope has spotted an eruption of dust around a young star, possibly the result of a smashup between large asteroids. This type of collision can eventually lead to the formation of planets. Scientists had been regularly tracking the star, called NGC 2547-ID8, when it surged with a huge amount of fresh dust between August 2012 and January 2013. “We think two big asteroids crashed into each other, creating a huge cloud of grains the size of very fine sand, which are now smashing themselves into smithereens and slowly leaking away from the star,” said lead author and graduate student Huan Meng of the University of Arizona, Tucson. …Rocky planets begin life as dusty material circling around young stars. The material clumps together to form asteroids that ram into each other. Although the asteroids often are destroyed, some grow over time and transform into proto-planets. After about 100 million years, the objects mature into full-grown, terrestrial planets. Our moon is thought to have formed from a giant impact between proto-Earth and a Mars-size object. …”We not only witnessed what appears to be the wreckage of a huge smashup, but have been able to track how it is changing — the signal is fading as the cloud destroys itself by grinding its grains down so they escape from the star,” said Kate Su of the University of Arizona and co-author on the study. “Spitzer is the best telescope for monitoring stars regularly and precisely for small changes in infrared light over months and even years.” …”We are watching rocky planet formation happen right in front of us,” said George Rieke, a University of Arizona co-author of the new study. “This is a unique chance to study this process in near real-time.” …The results of this study are posted online Thursday in the journal Science…. http://www.nasa.gov/press/2014/august/nasas-spitzer-telescope-witnesses-asteroid-smashup/. NASA RELEASE 14-226.
2014-08-17. Cassini Saturn mission Ten Year Top Science page: http://saturn.jpl.nasa.gov/news/cassinifeatures/10thannivdiscoveries/
Video about Cassini’s future:
Infographict, By The Numbers:
Ten Year Top Images:
Top Science of 2013:
Top Images of 2013:
2014-07-28. Cassini Spacecraft Reveals 101 Geysers and more on Icy Saturn Moon. NASA RELEASE 14-203. For GSS A Changing Cosmos chapter 7. Excerpt: Scientists using mission data from NASA’s Cassini spacecraft have identified 101 distinct geysers erupting on Saturn’s icy moon Enceladus. Their analysis suggests it is possible for liquid water to reach from the moon’s underground sea all the way to its surface. …After the first sighting of the geysers in 2005, scientists suspected repeated flexing of Enceladus by Saturn’s tides as the moon orbits the planet had something to do with their behavior. …Individual geysers were found to coincide with small-scale hot spots, only a few dozen feet (or tens of meters) across, which were too small to be produced by frictional heating, but the right size to be the result of condensation of vapor on the near-surface walls of the fractures. …“Once we had these results in hand we knew right away heat was not causing the geysers, but vice versa,” said Carolyn Porco, leader of the Cassini imaging team from the Space Science Institute in Boulder, Colorado, and lead author of the first paper. “It also told us the geysers are not a near-surface phenomenon, but have much deeper roots.” Additional details, images and an animation are available at: http://www.ciclops.org/view_event/202 More information about Cassini is available at: http://www.nasa.gov/cassini … http://www.nasa.gov/press/2014/july/cassini-spacecraft-reveals-101-geysers-and-more-on-icy-saturn-moon/#.U_t6YkiprZE
2014-04-24. Astronomical Forensics Uncover Planetary Disks in NASA’s Hubble Archive. Excerpt: Astronomers using NASA’s Hubble Space Telescope have applied a new image processing technique to obtain near-infrared scattered light photos of five disks observed around young stars in the Mikulski Archive for Space Telescopes database. These disks are telltale evidence for newly formed planets. If astronomers initially miss something in their review of data, they can make new discoveries by revisiting earlier data with new image processing techniques, thanks to the wealth of information stored in the Hubble data archive…. http://www.nasa.gov/press/2014/april/astronomical-forensics-uncover-planetary-disks-in-nasas-hubble-archive/#.U22cK8ePPAA. NASA Release 14-114.
2014-02-24. NASA to Hold Asteroid Initiative Opportunities Forum. For GSS A Changing Cosmos chapter 7. Excerpt: …NASA’s Asteroid Initiative includes two separate, but related activities: the Asteroid Redirect Mission and the Asteroid Grand Challenge. NASA is currently developing concepts for the mission, which will employ a robotic spacecraft to capture a small near-Earth asteroid, or remove a boulder from the surface of a larger asteroid, and redirect it into a stable orbit around the moon. Astronauts will travel aboard NASA’s Orion spacecraft, launched on the Space Launch System rocket, to rendezvous in lunar orbit with the captured asteroid material. Once there, they will collect samples to return to Earth for study. The grand challenge is seeking the best ideas to find all asteroid threats to human populations, and to accelerate the work that NASA is already doing for planetary defense. …NASA’s asteroid initiative: http://www.nasa.gov/asteroidinitiative …. http://www.nasa.gov/press/2014/february/nasa-to-hold-asteroid-initiative-opportunities-forum/#.UxYTT16aXKw. NASA Release 14-056.
2014-01-30. NASA-Sponsored ‘Disk Detective’ Lets Public Search for New Planetary Nurseries. Excerpt: NASA is inviting the public to help astronomers discover embryonic planetary systems hidden among data from the agency’s Wide-field Infrared Survey Explorer (WISE) mission through a new website, DiskDetective.org. Disk Detective is NASA’s largest crowdsourcing project whose primary goal is to produce publishable scientific results. …Astronomers have used computers to search this haystack of data for planet-forming environments and narrowed the field to about a half-million sources that shine brightly in the infrared, indicating they may be “needles”: dust-rich disks that are absorbing their star’s light and reradiating it as heat. …But galaxies, interstellar dust clouds, and asteroids also glow in the infrared, which stymies automated efforts to identify planetary habitats. … the only way to know for sure is to inspect each source by eye, which poses a monumental challenge…. http://www.nasa.gov/press/2014/january/nasa-sponsored-disk-detective-lets-public-search-for-new-planetary-nurseries/#.UvEuefYujhA. NASA RELEASE 14-038.
2014-01-22. Herschel Telescope Detects Water on Dwarf Planet. Excerpt: Scientists using the Herschel space observatory have made the first definitive detection of water vapor on the largest and roundest object in the asteroid belt, Ceres…. http://www.nasa.gov/press/2014/january/herschel-telescope-detects-water-on-dwarf-planet/#.Uuc84PbTl9I. NASA RELEASE 14-021.
2014-01-14. Dr. Ed Lu: Protecting Earth from Asteroids – Why We May Not See Them Coming. Excerpt: …more than a million “near-Earth asteroids” are larger than the asteroid that struck Tunguska, Siberia, in 1908 – and about 1,000 times more powerful than the atomic bomb dropped on Hiroshima. The 1908 asteroid was only about 40 meters across, yet it destroyed an area roughly the size of the San Francisco Bay Area. Nature magazine has just reported that “the risk of similar objects hitting our planet may be ten times larger than previously thought. Hear Dr. Lu’s lecture…. http://www.commonwealthclub.org/events/2014-01-14/dr-ed-lu-protecting-earth-asteroids-why-we-may-not-see-them-coming. Public lecture at The Commonwealth Club.
2013-04-15. NASA-Funded Asteroid Tracking Sensor Passes Key Test. http://www.nasa.gov/home/hqnews/2013/apr/HQ_13-109_Asteroid_Sensor.html – NASA RELEASE: 13-109 …An infrared sensor that could improve NASA’s future detecting and tracking of asteroids and comets has passed a critical design test. The test assessed performance of the Near Earth Object Camera (NEOCam) in an environment that mimicked the temperatures and pressures of deep space. NEOCam is the cornerstone instrument for a proposed new space-based asteroid-hunting telescope. …The sensor could be a vital component to inform plans for the agency’s recently announced initiative to develop the first-ever mission to identify, capture and relocate an asteroid closer to Earth for future exploration by astronauts. …NASA’s NEOWISE is an enhancement of the Wide-field Infrared Survey Explorer, or WISE, mission that launched in December 2009. WISE scanned the entire celestial sky in infrared light twice. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets close to Earth. NEOWISE completed its survey of small bodies, asteroids and comets, in our solar system. The mission’s discoveries of previously unknown objects include 21 comets, more than 34,000 asteroids in the main belt between Mars and Jupiter, and 134 near-NEOs.
2012-10-25. NASA Spacecraft Sees Huge Burp At Saturn After Large Storm | NASA Release 12-375. Excerpt: …”This temperature spike is so extreme it’s almost unbelievable, especially in this part of Saturn’s atmosphere, which typically is very stable,” said Brigette Hesman, the study’s lead author and a University of Maryland scientist who works at Goddard. “To get a temperature change of the same scale on Earth, you’d be going from the depths of winter in Fairbanks, Alaska, to the height of summer in the Mojave Desert.”
…According to Hesman, the huge spike of ethylene generated at the same
time peaked with 100 times more ethylene than scientists thought
possible for Saturn…. Full release at http://www.nasa.gov/home/hqnews/2012/oct/HQ_12-375_Cassini_Burp_Energy.html
Oct. 25, 2012
2012-10-17. Great new images of Uranus from Keck Observatory. See
2012-10-02. Amazing Meteor Boomerangs Around Earth | by SpaceWatchtower. Excerpt: For the first time ever, a meteor has grazed in and out of Earth’s atmosphere, slowing enough to become a temporary satellite that lasted a full orbit. Dynamicists believe a large meteoroid broke apart as it passed over Ireland on the night of September 21, 2012. Slowed by its atmospheric passage, the object entered a temporary orbit around Earth and returned to the sky over eastern North America 155 minutes later. …Martin Goff, an officer with the Greater Manchester [England] Police, was making his rounds when he spotted a dazzling meteor at 22:55 p.m. (21:55 Universal Time). …He estimates it was about as bright as a full moon and remained visible for 35 to 40 seconds, fragmenting for at least the last half of that. “I was just flabbergasted to have seen it!” …Dirk Ross, who tracks bright meteors and meteorite finds worldwide, logged 564 eyewitness reports from England, Scotland, Ireland, France, Belgium, The Netherlands, and Norway.. Read the full article: http://spacewatchtower.blogspot.com/2012/10/amazing-meteor-boomerangs-around-earth.html
2012-09-20. NASA Dawn Spacecraft Sees Hydrated Minerals on Giant Asteroid | by NASA Release 12-334. An article relevant to GSS A Changing Cosmos chapter 7. Excerpt: WASHINGTON — NASA’s Dawn spacecraft has revealed the giant asteroid Vesta has … volatile, or easily evaporated, materials … in a broad swath around its equator. … Pothole-like features mark some of the asteroid’s surface where the volatiles boiled off. Dawn … found evidence of hydrated minerals delivered by meteorites and dust in the giant asteroid’s chemistry and geology. The findings appear Thursday in the journal Science. “The source of the hydrogen within Vesta’s surface appears to be hydrated minerals delivered by carbon-rich space rocks that collided with Vesta at speeds slow enough to preserve their volatile content,” said Prettyman. …Scientists thought it might be possible for water ice to survive near the surface around the giant asteroid’s poles. Unlike Earth’s moon, however, Vesta has no permanently shadowed polar regions where ice might survive. The strongest signature for hydrogen in the latest data came from regions near the equator, where water ice is not stable….Escaping water left holes as much as six-tenths of a mile (1 kilometer) wide and as deep as 700 feet (200 meters). Seen in images from Dawn’s framing camera, this pitted terrain is best preserved in sections of Marcia crater. …To view new images and for more information about Dawn, visit: http://www.nasa.gov/dawn . Read the full article: http://www.nasa.gov/home/hqnews/2012/sep/HQ_12-334_Dawn_Minerals.html
2012-05-10. NASA Dawn Spacecraft Reveals Secrets of Large Asteroid | by NASA, NASA News RELEASE: 12-153. Excerpt: NASA’s Dawn spacecraft has provided researchers with the first orbital analysis of the giant asteroid Vesta, yielding new insights into its creation and relation to the terrestrial planets and Earth’s moon. Vesta now has been revealed as a special fossil of the early solar system … Vesta more closely resembles a small planet or Earth’s moon than another asteroid. Results appear in today’s edition of the journal Science. …Scientists now see Vesta as a layered, planetary building block with an iron core – the only one known to survive the earliest days of the solar system. The asteroid’s geologic complexity can be attributed to a process that separated the asteroid into a crust, mantle and iron core with a radius of approximately 68 miles (110 kilometers) about 4.56 billion years ago. The terrestrial planets and Earth’s moon formed in a similar way. …Data also confirm a distinct group of meteorites found on Earth did, as theorized, originate from Vesta. The signatures of pyroxene, an iron- and magnesium-rich mineral, in those meteorites match those of rocks on Vesta’s surface. These objects account for about 6 percent of all meteorites seen falling on Earth. This makes the asteroid one of the largest single sources for Earth’s meteorites. The finding also marks the first time a spacecraft has been able to visit the source of samples after they were identified on Earth… For more information about the Dawn mission, visit: http://www.nasa.gov/dawn
2012-04-25. NASA Dawn Spacecraft Reveals Secrets of Giant Asteroid Vesta. | by NASA, RELEASE: 12-134. Excerpt: …Findings from NASA’s Dawn spacecraft reveal new details about the giant asteroid Vesta, including its varied surface composition, sharp temperature changes and clues to its internal structure. … Many of the materials seen by Dawn are composed of iron- and magnesium-rich minerals, which often are found in Earth’s volcanic rocks. Images also reveal smooth pond-like deposits, which might have formed as fine dust created during impacts settled into low regions. …Dawn obtained the highest-resolution surface temperature maps of any asteroid visited by a spacecraft. Data reveal temperatures can vary from as warm as -10 degrees Fahrenheit (-23 degrees Celsius) in the sunniest spots to as cold as -150 degrees Fahrenheit (-100 degrees Celsius) in the shadows.
2011 Dec. The curious aftermath of Neptune’s discovery. By Deborah Kent, Physics Today, page 46. Excerpt: …The sensational news of Neptune’s observation reached the US about a month after the initial sighting at the Berlin Observatory just after midnight on 23 September 1846. The discovery was seen as a remarkable accomplishment of celestial mechanics. Not only was Neptune just the second major planet detected in recorded history, but the planet had been mathematically predicted before it was observed. …Neptune had been sighted before its 1846 discovery, but it had never been recognized as a major planet. In 1843 University of Cambridge graduate John Couch Adams began to pursue the idea that the well-documented orbital deviations of Uranus resulted from an unknown body, probably a planet. Astronomer Royal Airy ignored Adams’s computations. Telescope time from Cambridge Observatory director James Challis also eluded Adams, who needed observational data to confirm his prediction. In the summer of 1845, French scientist Urbain Jean Joseph LeVerrier also started to study the irregularities of the orbit of Uranus. …after a lukewarm reception from French observational astronomers, LeVerrier sent his request to Johann Galle at the Berlin Observatory. Galle agreed to look for the unknown planet, guided by LeVerrier’s prediction. Galle’s student assistant Heinrich Louis d’Arrest chose their complete copy of the detailed Berlin Academy star map for the project. According to d’Arrest, after less than an hour of observing, Galle reported “there is a star of the 8th magnitude in such and such a position, whereupon I immediately exclaimed: that star is not on the map!” The observation occurred 15 minutes after midnight on 23 September 1846. Although 19th-century contemporaries awarded the optical discovery to Galle, scholars now generally agree that Galle and d’Arrest jointly discovered the planet at the telescope in Berlin. Galle verified the initial observation the following night. The next morning he sent word to LeVerrier saying, “The planet whose position you have indicated really exists.” By 1 October, the news reached London, where it appeared in the Times. Controversy ensued. …Traditionally, historians have credited both LeVerrier and Adams with independent mathematical predictions for the location of the planet Neptune.
2011 Dec. The formation and differentiation of Earth. By Bernard Wood, Physics Today, page 40. Excerpt: The solar system began to form 4568 million years ago, from a disk of dust and gas around the young Sun. Within a few million years, Jupiter and Saturn had formed and the terrestrial planets had reached significant fractions of their present size. The processes by which the planets formed are of particular interest at a time when the search for Earth-like planets around other stars occupies considerable attention. Earth-like exoplanets somewhat larger than our own are already detectable, and criteria are being developed to identify stars around which smaller Earths should be present… …The planets of the solar system originated as dust and gas in the young Sun’s protoplanetary disk. The mechanisms of initial growth toward large bodies are poorly understood. But some combination of mechanical sticking and eventually gravitational perturbation must have formed many 10-km-sized objects in the first 104–105 years. At that size, gravitational perturbation becomes the dominant mechanism for further accretion through collision. Although some planetesimals would have been destroyed in collisions, others would have continued to accrete….
2011 Sep 16. Cool Video: Dawn Flies Around Vesta. Science@NASA Headline News. Excerpt: The data obtained by Dawn’s framing camera will help scientists determine the processes that formed asteroid Vesta’s striking features. It will also help Dawn mission fans all over the world visualize this mysterious world, which is the second most massive object in the main asteroid belt… [Article includes link to video]
2011 August 1. Scientists Stunned by Surface of Asteroid Vesta. By The Associated Press, The New York Times. Excerpt: The first close-up pictures of the massive asteroid Vesta reveal a northern hemisphere littered with craters — including a trio nicknamed “Snowman” — and a smoother southern half, researchers reported Monday.
…The images were taken by NASA’s Dawn spacecraft, which began orbiting the 330-mile-wide rocky body last month and beaming back incredible surface details that the team is only beginning to pore over. It’s the first time that Vesta has been viewed up close. Until now, it has only been photographed from afar.
…Currently some 117 million miles from Earth, Vesta is the second-largest resident of the asteroid belt, a zone between Mars and Jupiter filled with hundreds of thousands of space rocks orbiting the sun. The belt formed some 4.5 billion years ago around the same time and under similar conditions as Earth and the inner planets…
2011 May 25. NASA RELEASE 11-163: NASA To Launch New Science Mission To Asteroid in 2016. Excerpt: NASA will launch a spacecraft to an asteroid in 2016 and use a robotic arm to pluck samples that could better explain our solar system’s formation and how life began. The mission, called Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer, or OSIRIS-REx, will be the first U.S. mission to carry samples from an asteroid back to Earth….
…After traveling four years, OSIRIS-REx will approach the primitive, near Earth asteroid designated 1999 RQ36 in 2020. Once within three miles of the asteroid, the spacecraft will begin six months of comprehensive surface mapping. The science team then will pick a location from where the spacecraft’s arm will take a sample. The spacecraft gradually will move closer to the site, and the arm will extend to collect more than two ounces of material for return to Earth in 2023….
2011 May 9. A rare direct hit from a meteorite. By Emily Lakdawalla, The Planetary Society Blog. Excerpt: Meteorites hit Earth all the time, but they almost never score direct hits on human-built structures (or humans, for that matter). Most stories you’ll read on the Web about observed meteorite falls are either wrong or hoaxes. Once in a while, though, direct hits do happen, and it looks like this recent event in Poland was the real thing….
…It happened on April 30 in a rural village called Soltmany, just after 6:00 a.m. local time. A cobble-sized rock weighing about a kilogram came down nearly vertically and smashed right through a roof:
After crashing through the roof it smashed into a concrete path and broke into several pieces….
…The meteorite has a nice conical shape and an obvious fusion crust, both resulting from its high-speed descent through Earth’s atmosphere; tests will be needed to make sure of its extraterrestrial origin but it’s got all the right qualities to be a real meteorite….
2011 May 3. NASA RELEASE 11-133: NASA Dawn Spacecraft Reaches Milestone Approaching Asteroid. Excerpt: NASA’s Dawn spacecraft has reached its official approach phase to the asteroid Vesta and will begin using cameras for the first time to aid navigation for an expected July 16 orbital encounter. The large asteroid is known as a protoplanet – a celestial body that almost formed into a planet….
…Dawn’s odyssey, which will take it on a 3-billion-mile journey, began on Sept. 27, 2007, with its launch from Cape Canaveral Air Force Station in Florida. It will stay in orbit around Vesta for one year. After another long cruise phase, Dawn will arrive at its second destination, an even more massive body in the asteroid belt called Ceres, in 2015….
…The mission will compare and contrast the two giant asteroids, which were shaped by different forces. Dawn’s science instrument suite will measure surface composition, topography and texture. In addition, the Dawn spacecraft will measure the tug of gravity from Vesta and Ceres to learn more about their internal structures….
2009 December. From Particles to Planets. By Kathleen M. Wong, ScienceMatters@Berkeley. Excerpt: Dust, to most of us, is nothing more than a nuisance. The grayish film that collects atop bookshelves and beneath the couch is the bane of housekeepers from Arkhangelsk to Zimbabwe. But Eugene Chiang, a Berkeley professor of astronomy and earth and planetary science, says dust deserves more respect. It is, after all, the foundation upon which entire worlds are built.
A theoretical astrophysicist, Chiang studies how planetary systems form, “starting from disks of gas and micron-sized particles in orbit around young stars, and ending with congealed objects as massive as Jupiter,” he says.
How dust agglomerates into something the size of a planet remains a subject of hot debate. The trick, in terms of physics, is getting started. What mechanisms could drive specks of dust to clump in the first place? One possibility is by collisions. In this scenario, dust particles carom off one another until, by chance, a few begin to stick. But as anyone who has dropped one rock atop another knows, they easily rebound, chip, or shatter.
Chiang sees a different mechanism at play. He envisions gravity gently pulling ensembles of grains together until they coalesce into giant masses. “Grains might settle towards the midplanes of disks into a thin and dense enough layer that they can self-gravitate into objects easily kilometers in size. You jump from microns to kilometers, and then you’re on your way to forming even larger objects,” Chiang says.
…In the 1990s, scientists discovered that magnetic fields could brake the rotation of the gas disk and allow gas to stream inward. Chiang is investigating whether this mechanism is at play in the centers of donut-hole systems.
Magnetic fields strongly influence charged particles such as electrons and ions but have no influence on uncharged materials such as wood. By considering a wide array of chemical reactions occurring within the disk, Chiang and physics graduate student Daniel Perez-Becker are calculating how much free charge exists in young solar systems, to assess the relevance of magnetic fields.
…More fully formed solar systems hold equal allure for Chiang. In 2005, Berkeley astronomers Paul Kalas and James Graham spotted a planet circling a nearby star called Fomalhaut. Images of the planet consist of little more than a few pixels of light. Even so, Chiang was still able to deduce considerable information from them….
2009 July 21. NASA images show Jupiter apparently hit by object. Pasadena, Calif. (AP) — Astronomers say Jupiter has apparently been struck by an object, possibly a comet. Images taken by NASA early Monday show a scar in the atmosphere near the south pole of the gas giant. The images, taken by the space agency’s infrared telescope in Hawaii, come on the 15th anniversary of another comet strike. In 1994, Jupiter was bombarded by pieces of the comet Shoemaker-Levy 9. Scientists at NASA’s Jet Propulsion Laboratory in Pasadena captured the new images after receiving a tip from an amateur astronomer the night before. See also:
Amateur Finds New Earth-Sized Blot on Jupiter – NASA has confirmed the discovery of a new “scar” the size of the Earth in Jupiter’s atmosphere, apparently showing that the planet was hit by something large in recent days.
NASA RELEASE: 09-176. Hubble Space Telescope Captures Rare Jupiter Collision. – NASA’s Hubble Space Telescope has taken the sharpest visible-light picture yet of atmospheric debris from an object that collided with Jupiter on July 19.
2009 April. Journey to Jupiter. National Geographic video — naked science series. Ganymede has a molten core.
2009 January 16. A Better View of the Planets. By Kathleen M. Wong, ScienceMatters@Berkeley, Volume 6, Issue 40. Excerpt: What’s the weather like on Jupiter? Berkeley professor of astronomy Imke de Pater knows. De Pater and her colleagues have tracked the planet’s titanic and long-lasting storms, observed its icy ammonia clouds, and mapped the structure of its violent atmosphere. In other work, they’ve discovered methane drizzle on Saturn’s moon Titan, modeled Jupiter’s magnetic fields, and revealed the dynamic behavior of Neptune’s skies.
…Most astronomers use ground-based telescopes to study the skies. But the drawback of viewing the cosmos from Earth is the turbulence in our atmosphere. True to her innovative style, de Pater has been pushing the limits of a newer technique known as adaptive optics (AO) to improve the quality of ground-based observations.
The method uses a reference light source near the target, such as a laser beam or adjacent moon, or in some cases the object of interest itself to quantify the degree of atmospheric turbulence, and correct the data online with help of a deformable mirror. The result: a crisp and astonishingly detailed picture.
…”If you look through a conventional telescope, you can just barely see the rings around Uranus, and you certainly don’t see atmospheric details,” de Pater says. By contrast, the details in her AO images of the planet rival the shots sent back by the Voyager spacecraft during its 1986 Uranus flyby….
2008 October 16. Shocking start for the solar system By Stephen G. Benka. Excerpt: In the 1970s, the hypothesis arose that our solar system was formed by a passing shock wave from a supernova, which triggered the collapse of an interstellar cloud into a dense region of gas and dust that further contracted to become the Sun and its orbiting planets. The original evidence came from very old meteorites that contained magnesium-26, a daughter product of the short-lived radioactive isotope (SLRI) aluminum-26-produced in stellar nucleosynthesis. Further evidence came from another SLRI, nickel-60, which can only be produced in a supernova’s furnace. In astronomical terms, short-lived means a half-life of about a million years; any SLRIs would have been transported to, and dropped off in, the pre-solar cloud faster than that time scale. Computer modelers from the late 1990s, however, could not produce both the collapse and the injection of supernova material unless they artificially prevented the shock wave from heating the cloud. That situation has now been remedied by a group from the Carnegie Institution of Washington, who used a modern, adaptive-grid computer code with an improved treatment of heating and cooling. Their new models show that a supernova’s shock wave moving into an otherwise stable solar-mass cloud can both trigger the collapse and leave behind enriched gas and dust, including the SLRIs whose products are found in meteorites. Furthermore, the researchers found that a protostar began to form in less than 200?000 years, in the blink of an astronomical eye. (A. P. Boss et al., Astrophys. J. Lett. 686, L119, 2008.)
2008 June 17. A Bounty of Midsize Planets is Reported. By Dennis Overbye, The New York Times. Excerpt: There is a lot of new territory out there in the cosmos, but nothing you would want to pitch camp on — yet.
About a third of all the Sun-like stars in our galaxy harbor modestly sized planets, according to a study announced Monday by a team of European astronomers.
At a meeting in Nantes, France, Michel Mayor of the Geneva Observatory and his group presented a list of 45 new planets, ranging in mass from slightly bigger than Earth to about twice as massive as Neptune, from a continuing survey of some 200 stars.
All of the planets orbit their stars in 50 days or less, well within the corresponding orbit of Mercury, which takes 88 days to go around the Sun, and well within frying distance of any lifelike creatures.
Dr. Mayor called the discoveries “only the tip of the iceberg” in a news release from the European Southern Observatory in Garching, Germany.
About one in 14 stars harbors a massive giant planet like Jupiter or Saturn, Dr. Mayor estimated. If in fact one in three harbors a Neptune or super-Earth, that is an appealing situation for astronomers and others who would like someday to find someplace livable or even someone living Out There…