2022-08-25. Brighter Skies Ahead—As solar max approaches, new tech is on call. [https://eos.org/agu-news/brighter-skies-ahead] By Heather Goss, Eos/AGU. Excerpt: …An impressive cadre of Sun-targeted missions has recently come online to replace or support an aging fleet of spacecraft, just as solar max is about to set in. …In February 2020, Solar Orbiter launched from Florida, carrying 10 state-of-the-art instruments to make the closest ever observations of the Sun. Daniele Telloni and colleagues, in “A New Journey Around (and Around) the Sun,” describe for us “the groundbreaking observations that Solar Orbiter has made already,” such as the “short-lived, small-scale flickering bright spots, nicknamed ‘campfires,’ in the solar corona.” Not only will this joint European Space Agency–NASA mission shed new light on the unsolved mysteries of the Sun, but also it’s revealing a new side of Venus from its 2020 flyby. …in our next feature, “Shake, Rattle, and Probe.” Helioseismology is a burgeoning discipline that allows physicists to better understand the structure of our star. …“11 Discoveries Awaiting Us at Solar Max,” get excited about peering inside coronal mass ejections, creating “Sun to mud” predictions, and better understanding magnetic fields throughout our solar system.…
2020-05-11. Space Weather Forecasting Takes Inspiration from Meteorology. By Sarah Stanley, Eos/AGU. Excerpt: Every so often, the Sun unleashes powerful bursts of plasma particles and magnetic field structures toward Earth. These solar storms can wreak havoc on power grids [https://eos.org/features/the-geomagnetic-blitz-of-september-1941], satellites [https://eos.org/editor-highlights/space-traffic-management-better-space-weather-forecasts-needed], and other infrastructure, but they are difficult to predict more than a few days in advance. In a new review, Dikpati and McIntosh [https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018SW002109] showcase mounting evidence that solar storms arise from solar Rossby waves, a type of wave associated with rotating fluids. Just as the 1939 discovery of Rossby waves [https://www.weather.gov/jetstream/longshort] in Earth’s atmosphere paved the way to accurate weather prediction, Rossby waves in the Sun could be key to predicting disruptive space weather in time to prepare for it. On Earth, atmospheric Rossby waves arise from the planet’s rotation, and these large-scale meandering features help transport warm air toward the poles and cold air toward the tropics. Earth’s Rossby waves sometimes have extreme effects, such as those from 2019’s polar vortex…. [https://eos.org/research-spotlights/space-weather-forecasting-takes-inspiration-from-meteorology]
2017-07-14. Unlocking Mysteries in the Sun’s 11-Year Cycle. By Nicholas St. Fleur. Excerpt: According to a study published Thursday in the journal Science, our beloved star can be classified as an ordinary “solar-type” star, meaning that the internal processes that control its activity are similar to those seen in many other nearby stars. The sun goes through an 11-year cycle where its magnetic poles flip — imagine the north and south poles on Earth changing place — and during this time the sun’s activity changes between subdued and tumultuous. When activity is low, it is known as solar minimum, and when activity is high, it is known as solar maximum. As the sun nears solar maximum and its activity cycle ramps up, its surface gets covered in sunspots, which are ephemeral dark marks created by strong magnetic activity. “Above sunspots you have complex structures that trigger dynamic phenomenons, eruptions that are like volcanoes,” said Antoine Strugarek, a solar physicist at the French Alternative Energies and Atomic Energy Commission and at the University of Montreal. “Those eruptions can impact our Earth.” …In a study published Friday in the journal Science Advances, Dr. Morgan found that when the sun is at solar minimum, the quiet corona measures around 1.4 million degrees Celsius. But at solar maximum it jumps to around 1.8 million degrees. Dr. Morgan said he was not sure why the entire corona, including the areas not above a sunspot, heat up as the sun’s activity increases. “The solar corona remains a mystery,” he said. “But we are getting far better at measuring what it’s doing and that’s enabling us to start to understand it.”…. https://www.nytimes.com/2017/07/14/science/sun-cycles-solar-maximum-minimum-corona.html
2017-06-23. Solving the Scorching Mystery of the Sun’s Erupting Plasma Jets. By Nicholas St. Fleur, The New York Times. Excerpt: Spiky bursts of plasma called spicules swirl around the surface of the sun. Millions erupt every moment, spurting solar material some 6,000 miles high at speeds of about 60 miles per second. “These things are very violent,” said Bart De Pontieu, a research scientist with Lockheed Martin Solar and Astrophysics Lab in Palo Alto, Calif. “The gas in spicules is about 10,000 degrees and they travel the length of California in just a minute or so.” Scientists have studied spicules for decades, but were not sure how the plasma jets formed. Now, Dr. De Pontieu and his colleagues think they have solved the searing mystery. They published their findings Thursday in the journal Science. …they created a computer simulation that reconstructed the conditions between the sun’s surface and its atmosphere, where spicules form. Powerful magnetic fields are created in the interior of the sun. There, the high density keeps them tangled and tamed. But near the surface, the magnetic fields can use neutral particles, atoms that do not carry an electric charge, to diffuse into the sun’s atmosphere. The fields enter a reddish layer called the chromosphere where their violent nature is unleashed. “It’s a sling shot effect,” said Mats Carlsson, a professor of astrophysics at the University of Oslo in Norway, and co-author of the paper. The density in the chromosphere is significantly lower than in the sun’s interior, so the magnetic fields are no longer suppressed and are able to straighten out. As they unwind and release their tension, they fling hot plasma at incredible speeds, creating the spicules. The spicules surge thousands of miles high, passing through the chromosphere and into the sun’s corona before collapsing…. https://www.nytimes.com/2017/06/23/science/sun-plasma-jets-spicules.html
2017-05-18. Humans Accidentally Made a Space Cocoon For Ourselves Out of Radio Waves. By Becky Ferreira for Motherboard. Excerpt: Humans have accidentally created a protective bubble around Earth by using very low frequency (VLF) radio transmissions to contact submarines in the ocean. It sounds nuts, but according to recent research published in Space Science Reviews, underwater communication through VLF channels has an outer space dimension. …Satellites in certain high-altitude orbits, such as NASA’s particle-watching Van Allen Probes, have observed these VLF ripples creating an “impenetrable boundary,” a phrase coined by study co-author Dan Baker, director of the University of Colorado’s Laboratory for Atmospheric and Space Physics. This doesn’t mean impenetrable to spacecraft or asteroids, per se, but rather to potentially harmful particle showers created by turbulent space weather. …The boundary extends out to the inner edge of the Van Allen radiation belts, which are bands of charged particles created from the clash of the solar wind against Earth’s magnetic field. The VLF bubble might actually be pushing the Van Allen belts farther into space, suggests Baker, considering that they have receded farther from Earth since the 1960s, when VLF use was not as widespread…. https://motherboard.vice.com/en_us/article/nasa-space-weather-earth-cocoon-van-allen
2017-02-17. How Space Weather Can Influence Elections on Earth. By Becky Ferreira for Motherboard. Excerpt: The real alien voter fraud is genuinely coming from outside our planet. …The Sun, which is emphatically not registered to vote, dabbles in casting ballots on Earth, according to a presentation given by Bharat Bhuva, a professor of electrical engineering at Vanderbilt University, on Friday morning at the annual meeting of the American Association for the Advancement of Science (AAAS) in Boston. Bhuva specializes in assessing the risk of space weather damaging electrical systems on and around Earth, including electronic voting systems. He brought up one instance of a federal election held in the city of Schaerbeek, Belgium in 2003, in which one of the candidates ended up with 4,096 extra votes. “Everything was going fine, but then suddenly, there were an additional 4,000 votes cast […] People were surprised and asked, ‘how did this happen?'” The culprit was not voter fraud or hacked machines. It was most likely a single event upset (SEU), a term describing the fallout of an ionizing particle bouncing off a vulnerable node in the machine’s register, causing it to flip a bit, and log the additional votes. The Sun may not have been the direct source of the particle—cosmic rays from outside the solar system are also in the mix—but solar-influenced space weather certainly contributes to these SEUs…. https://motherboard.vice.com/en_us/article/space-weather-cosmic-rays-voting-aaas
2016-09-15. The Geomagnetic Blitz of September 1941. By Jeffrey J. Love and Pierdavide Coïsson, for Earth and Space News EOS (AGU). Excerpt: Seventy-five years ago next week, a massive geomagnetic storm disrupted electrical power, interrupted radio broadcasts, and illuminated the night sky in a World War II battle theater. …Auroras danced across the night sky as voltage surged in power grid lines. A radio blackout interrupted fan enjoyment of a baseball game, while another radio program was interrupted by private phone conversations. …And far away in the North Atlantic, the illuminated night sky exposed an Allied convoy to German attack. …On the basis of daily sunspot reports supplied by the U.S. Naval Observatory, the Department of Terrestrial Magnetism at the Carnegie Institution of Washington formally issued a warning to radio operators that they could expect significant disturbances to ionospheric and geomagnetic conditions beginning on about 18 September…. This prediction, which turned out to be accurate, is a noteworthy development in the historical development of methods for reliably forecasting space weather. Less than 20 hours after the flare was reported by Greenwich, a magnetic storm commenced at 0412 UT on 18 September with the arrival at Earth of a coronal mass ejection. …On 18–19 September 1941, the Moon was nearly new, ideal for seeing the auroral light…. The observer in charge at the Cheltenham, Md., observatory reported a brilliant auroral display of rays and moving drapery of pink, green, and lavender. He also described an auroral corona, where light appears to stream down from directly overhead, a phenomenon rarely seen at midcontinental latitudes. …Weather Service observers reported seeing auroras in New Mexico [Cameron, 1941]. …at 19:45 and 19:50 UT, the Pennsylvania Water and Power Company recorded uncontrolled voltage variations in transmission lines connecting generating plants on the Susquehanna River with Baltimore and Washington. At the moment when the auroral brilliance was greatest, system transformers vibrated and groaned as a result of geomagnetically induced currents…. https://eos.org/features/the-geomagnetic-blitz-of-september-1941 See also Scientists Get First Glimpse of Solar Wind as It Forms.
2016-02-24. Sun’s Magnetic Fields Best at Forecasting Solar Cycle Peaks. By Aleida K. Higginson, EoS-Earth & Space Science News, AGU. Excerpt: Solar activity level rises and falls every 11 years. The most recent maximum in solar activity level, the 24th since recording began in 1755, was the weakest in almost 100 years and peaked in early 2014. Solar activity refers to dark regions on the surface of the Sun called sunspots, where the Sun’s magnetic field has become tangled. They can produce sudden explosions of energy in the form of intense radiation and energetic particles. Sometimes, these regions will even kick out a portion of the tangled magnetic field and send it hurdling into space in an event called a coronal mass ejection. When these bursts of radiation, particles, and magnetic field reach Earth, they cause geomagnetic storms, which can interfere with communication satellites and power grids on the ground. These events could also be harmful to astronauts traveling to Mars, exposing them to possibly deadly amounts of radiation. …a new study by Pesnell compares all of the predictions to determine which forecasts were the most accurate. … For past solar cycles, models using geomagnetic activity level made more accurate predictions, but this accuracy may be due to the fact that solar polar magnetic field data were scarce or unreliable. This time, for solar cycle 24, the models using polar magnetic fields made the best predictions by far. …solar cycle 25, slated to begin as early as 2020…. (Space Weather, doi:10.1002/2015SW001304, 2016)… https://eos.org/research-spotlights/suns-magnetic-fields-best-at-forecasting-solar-cycle-peaks
2015-12-07. Model of Solar Cycle’s Impact on Climate Gets Upgrade. By Mark Zastrow, EoS Earth & Space Science News. xcerpt: …Over the course of the 11-year cycle, the rotation of the Sun slowly twists its magnetic field into knots, creating dark sunspots. Although the overall brightness of the Sun varies by only 0.1%, the twisted bundles of magnetic energy can boost its ultraviolet (UV) radiation by 4%–8% at the solar cycle’s peak. These powerful UV rays trigger chemical reactions in the stratosphere that bind oxygen atoms and molecules to form ozone. Since ozone itself is a good absorber of UV radiation, it can heat the stratosphere near the equator, which affects the winds that circle the globe. Increased solar activity also excites Earth’s magnetic field, sending high-energy particles hurtling into the upper atmosphere. During the long polar night, this can generate large amounts of the nitrogen compounds nitric oxide (NO) and nitrogen dioxide (NO2), which eventually descend into the stratosphere and destroy ozone. To study the effects of these often-competing processes, scientists construct simulations using models such as the Whole Atmosphere Community Climate Model (WACCM) produced by the National Center for Atmospheric Research…. https://eos.org/research-spotlights/model-of-solar-cycles-impact-on-climate-gets-upgrade
2015-11-06. White House Plan Focuses on Hazards from Solar Storms. By Randy Showstack, EoS Earth & Space Science News, AGU. Excerpt: Space weather has its day in the Sun, with the administration issuing a new strategy and action plan to increase protection from damaging solar emissions. …Space weather events occur when outbursts from the Sun, such as solar flares, solar energetic particles, and coronal mass ejections, collide with Earth’s magnetic field. Although many of these events are harmless, some are powerful enough to cause havoc by disrupting critical technology. Speakers at the forum referred to a 1989 geomagnetic storm that cut electricity to 6 million Canadians for 9 hours and to the 1859 “Carrington” event, the largest documented series of geomagnetic storms from the Sun to have struck Earth…. https://eos.org/articles/white-house-plan-focuses-on-hazards-from-solar-storms
2014-07-01. A Solar Show With Mixed Reviews. Excerpt: …the maximum — the peak of the 11-year sunspot cycle, when the sun erupts with solar flares and energetic bursts of electrons and protons — may have already passed. As solar maximums go, this has been a tepid one, particularly when measured against some predictions that it would be ferocious; it has been called a “minimax.” But neither does it rival a quiet period in the second half of the 1600s that coincided with the onset of the Little Ice Age, a prolonged chill in Europe. …“I think the general consensus is that we’ve passed the peak,” said C. Alex Young, a solar astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Md. But he added that some of the biggest solar storms in history occurred on the downward side of the solar cycle, and even a weak cycle can generate ferocious outbursts. “I think the expectation right now is we might see another burst of this activity five or six months from now,” Dr. Young said. “We might still have some big events.”… http://www.nytimes.com/2014/07/01/science/a-solar-show-with-mixed-reviews.html. By Kenneth Chang, The New York Times.
2013-01-08. Solar Variability and Terrestrial Climate | NASA Science News. Excerpt: …In the galactic scheme of things, the Sun is a remarkably constant star. While some stars exhibit dramatic pulsations, wildly yo-yoing in size and brightness, and sometimes even exploding, the luminosity of our own sun varies a measly 0.1% over the course of the 11-year solar cycle. There is, however, a dawning realization among researchers that even these apparently tiny variations can have a significant effect on terrestrial climate. A new report issued by the National Research Council (NRC), “The Effects of Solar Variability on Earth’s Climate” [at http://www.nap.edu/catalog.php?record_id=13519] lays out some of the surprisingly complex ways that solar activity can make itself felt on our planet. …Greg Kopp of the Laboratory for Atmospheric and Space Physics at the University of Colorado, pointed out that … “Even typical short term variations of 0.1% in incident irradiance exceed all other energy sources (such as natural radioactivity in Earth’s core) combined,” he says. Of particular importance is the sun’s extreme ultraviolet (EUV) radiation, which …varies not by a minuscule 0.1%, but by whopping factors of 10 or more. This can strongly affect the chemistry and thermal structure of the upper atmosphere. …In recent years, researchers have considered the possibility that the sun plays a role in global warming. After all, the sun is the main source of heat for our planet. The NRC report suggests, however, that the influence of solar variability is more regional than global…. Read the full article: http://science.nasa.gov/science-news/science-at-nasa/2013/08jan_sunclimate/
2010 Summer. Probing the Solar Plasma. By Kathleen M. Wong, Science Matters @ Berkeley. Excerpt: …“From just outside earth’s atmosphere all the way to the part of the sun you see during the day, is all plasma,” says Stuart Bale. A Berkeley professor of physics and director of the university’s Space Sciences Laboratory, Bale studies the plasmas that stream from stars and suffuse entire galaxies.
…Bale has submitted a proposal for an experiment that will study the acceleration and heating of the solar wind. The wind originates as plasma evaporating from the sun’s relatively cool 5,000 to 6,000 degree Celsius surface. As it expands and rises into the corona, the radiant solar “atmosphere” only visible during a total solar eclipse, this plasma grows hotter and faster until it is roaring through the solar system at more than a million kilometers per hour.
…“There has to be some collisionless process that’s heating the plasma. There has to be some place for that energy cascading into smaller and smaller scales to go,” Bale says. To observe that transfer of heat, Bale has proposed to measure the electromagnetic fields in the corona and the temperature at the same time. In this way, he can link the behavior of the fields to the transfer of heat.
…Though the theory seems to fit, details of the process aren’t known. The information gleaned from the experiment will then help characterize the physics of black hole accretion disks, galaxy clusters, and other stars. “Heating coronas is a universal astrophysical problem,” Bale says.
2009 Feb 11. Solar Dynamics Observatory successfully launched Feb 11. Mission Science Objectives–The scientific goals of the SDO Project are to improve our understanding of seven science questions:
1. What mechanisms drive the quasi-periodic 11-year cycle of solar activity?
2. How is active region magnetic flux synthesized, concentrated, and dispersed across the solar surface?
3. How does magnetic reconnection on small scales reorganize the large-scale field topology and current systems and how significant is it in heating the corona and accelerating the solar wind?
4. Where do the observed variations in the Sun’s EUV spectral irradiance arise, and how do they relate to the magnetic activity cycles?
5. What magnetic field configurations lead to the CMEs, filament eruptions, and flares that produce energetic particles and radiation?
6. Can the structure and dynamics of the solar wind near Earth be determined from the magnetic field configuration and atmospheric structure near the solar surface?
7. When will activity occur, and is it possible to make accurate and reliable forecasts of space weather and climate?
2009 Sep 17. Solar Cycle Driven by More than Sunspots. NSF Press Release 09-171. Excerpt: Challenging conventional wisdom, new research finds that the number of sunspots provides an incomplete measure of changes in the Sun’s impact on Earth over the course of the 11-year solar cycle. The study, led by scientists at the National Center for Atmospheric Research (NCAR) and the University of Michigan, finds that Earth was bombarded last year with high levels of solar energy at a time when the Sun was in an unusually quiet phase and sunspots had virtually disappeared….
2009 Jul 20. Is the Sun Missing Its Spots? [photos show sunspots near solar maximum on July 19, 2000, and near solar minimum on March 18, 2009. Some global warming skeptics speculate that the Sun may be on the verge of an extended slumber.] By Kenneth Chang, The NY Times. Excerpt: The Sun is still blank (mostly).
Ever since Samuel Heinrich Schwabe, a German astronomer, first noted in 1843 that sunspots burgeon and wane over a roughly 11-year cycle, scientists have carefully watched the Sun’s activity. In the latest lull, the Sun should have reached its calmest, least pockmarked state last fall.
Indeed, last year marked the blankest year of the Sun in the last half-century – 266 days with not a single sunspot visible from Earth. Then, in the first four months of 2009, the Sun became even more blank, the pace of sunspots slowing more….
2009 May 29. New Solar Cycle Prediction. By Dr. Tony Phillips, Science@NASA. An international panel of experts has issued a new prediction for the solar cycle that takes into account the surprisingly deep solar minimum of 2008-2009. Find out when they think solar maximum will return.
2007 April 24. NASA Releases 3D Images of Sun. By THE ASSOCIATED PRESS. Excerpt: GREENBELT, Md. (AP) — NASA released the first three-dimensional images of the sun Monday, saying the photos taken from twin spacecraft may lead to better predictions of solar eruptions that can affect communications and power lines on Earth. … ‘Wow!”’ scientist Simon Plunkett said as he explained the images to a room full of journalists and scientists wearing 3D glasses. The images from the STEREO spacecraft (for Solar Terrestrial Relations Observatory) are available on the Internet and at museums and science centers nationwide. The twin spacecraft, launched in October, are orbiting the Sun, one slightly ahead of the Earth and one behind. The separation, just like the distance between our two eyes, provides the depth perception that allows the 3D images to be obtained. That depth perception is also particularly helpful for studying a type of solar eruption called a coronal mass ejection. Along with overloading power lines and disrupting satellite communications, the eruptions can endanger astronauts on spacewalks. Scientists would like to improve predictions of the arrival time from the current day or so to a few hours, said Russell Howard, principal investigator for the Naval Research Laboratory project. Seehttp://www.nasa.gov/stereo2005 May 24. Solar Fireworks Signal New Space Weather Mystery. NASA RELEASE 05-132. The most intense burst of solar radiation in five decades accompanied a large solar flare on January 20. It shook space weather theory and highlighted the need for new forecasting techniques, according to several presentations at the American Geophysical Union (AGU) meeting this week in New Orleans. The solar flare, which occurred at 2 a.m. EST, tripped radiation monitors all over the planet and scrambled detectors onTspacecraft. The shower of energetic protons came minutes after the first sign of the flare. This flare was an extreme example of the type of radiation storm that arrives too quickly to warn interplanetary astronauts. “This flare produced the largest solar radiation signal on the ground in nearly 50 years,” said Dr. Richard Mewaldt of the California Institute of Technology, Pasadena, Calif. … “But we were really surprised when we saw how fast the particles reached their peak intensity and arrived at Earth.” Normally it takes two or more hours for a dangerous proton shower to reach maximum intensity at Earth after a solar flare. The particles from the January 20 flare peaked about 15 minutes after the first sign. …The Transitional Region and Coronal Explorer (TRACE) … has identified a possible source of the magnetic stress that causes solar flares. The sunspots that give off the very largest (X-class) flares appear to rotate in the days around the flare. “This rotation stretches and twists the magnetic field lines over the sunspots”, Nightingale said. “We have seen it before virtually every X-flare that TRACE has observed since it was launched and more than half of all flares in that time.” However, rotating sunspots are not the whole story. The unique flare came at the end of a string of five other very large flares from the same sunspot group, and no one knows why this one produced more sudden high energy particles than the first four. “It means we really don’t understand how the sun works,” Lin said. “We need to continue to operate and exploit our fleet of solar-observing spacecraft to identify how it works.”
24 May 2005. Solar Fireworks Signal New Space Weather Mystery. NASA RELEASE 05-132. The most intense burst of solar radiation in five decades accompanied a large solar flare on January 20. It shook space weather theory and highlighted the need for new forecasting techniques, according to several presentations at the American Geophysical Union (AGU) meeting this week in New Orleans. The solar flare, which occurred at 2 a.m. EST, tripped radiation monitors all over the planet and scrambled detectors on spacecraft. The shower of energetic protons came minutes after the first sign of the flare. This flare was an extreme example of the type of radiation storm that arrives too quickly to warn interplanetary astronauts. “This flare produced the largest solar radiation signal on the ground in nearly 50 years,” said Dr. Richard Mewaldt of the California Institute of Technology, Pasadena, Calif. … “But we were really surprised when we saw how fast the particles reached their peak intensity and arrived at Earth.” Normally it takes two or more hours for a dangerous proton shower to reach maximum intensity at Earth after a solar flare. The particles from the January 20 flare peaked about 15 minutes after the first sign. …The Transitional Region and Coronal Explorer (TRACE) … has identified a possible source of the magnetic stress that causes solar flares. The sunspots that give off the very largest (X-class) flares appear to rotate in the days around the flare. “This rotation stretches and twists the magnetic field lines over the sunspots”, Nightingale said. “We have seen it before virtually every X-flare that TRACE has observed since it was launched and more than half of all flares in that time.” However, rotating sunspots are not the whole story. The unique flare came at the end of a string of five other very large flares from the same sunspot group, and no one knows why this one produced more sudden high energy particles than the first four. “It means we really don’t understand how the sun works,” Lin said. “We need to continue to operate and exploit our fleet of solar-observing spacecraft to identify how it works.”
18 October 2004. Science@NASA. Solar physicist David Hathaway has been checking the sun every day since 1998, and every day for six years there have been sunspots. Sunspots are planet-sized “islands” on the surface of the sun. They are dark, cool, powerfully magnetized, and fleeting: a typical sunspot lasts only a few days or weeks before it breaks up. As soon as one disappears, however, another emerges to take its place. Even during the lowest ebb of solar activity, you can usually find one or two spots on the sun. But when Hathaway looked on Jan. 28, 2004, there were none. The sun was utterly blank. It happened again last week, twice, on Oct. 11th and 12th. There were no sunspots. “This is a sign,” says Hathaway, “that the solar minimum is coming, and it’s coming sooner than we expected.
12 July 2001. GREATER SOLAR ACTIVITY MAY BRING U.S. MORE GRAY DAYS — Also here