3. Cosmic Engines


Articles from 2005–present

2021-05-21. [https://eos.org/articles/record-setting-flare-spotted-on-the-nearest-star-to-the-sun] - Record-Setting Flare Spotted on the Nearest Star to the Sun. Source: By Katherine Kornei, Eos/AGU. Excerpt: As stellar neighbors go, the Sun is a pretty good one—it occasionally produces a sizeable solar flare, but mostly, it leaves Earth well enough alone. The Proxima Centauri solar system isn’t so lucky, however: Blasts of electromagnetic radiation from Proxima Centauri, the next nearest star to our own, can be potentially lethal to nearby planets. Researchers recently spotted the brightest stellar flare ever detected from Proxima Centauri. That flare might have contributed to stripping away the atmosphere of one of its planets, a roughly Earth mass world that potentially hosts liquid water on its surface. ...Destroyer of Atmospheres ...Proxima Centauri’s faintness stems from its low mass—it’s what astronomers refer to as an M dwarf star, defined as having a mass between roughly 10% and 50% the mass of the Sun. M dwarf stars are the most common stars in the Milky Way, but they come with a reputation, said Meredith MacGregor, an astronomer at the University of Colorado Boulder. “M dwarfs are vastly more active than the Sun.” That means they regularly emit stellar flares, blasts of electromagnetic radiation launched by their host star’s magnetic field. These streams of photons can be destructive, said MacGregor. When high-energy ultraviolet radiation collides with a planet’s atmosphere, it can disassociate molecules like water and ozone, splitting them into their constituent atoms. Some of those lighter atoms can then drift away and escape. “You can basically erode away the atmosphere of a planet,” said MacGregor.... 

2020-07-16. Solar Orbiter's First Images Reveal "Campfires" on the Sun. By European Space Agency (ESA). Excerpt: The first images from Solar Orbiter, a new Sun-observing mission by ESA and NASA, have revealed omnipresent miniature solar flares, dubbed 'campfires', near the surface of our closest star. ...Solar Orbiter, launched on 10 February 2020, carries six remote-sensing instruments... and four in situ instruments that monitor the environment around the spacecraft. By comparing the data from both sets of instruments, scientists will get insights into the generation of the solar wind, the stream of charged particles from the Sun that influences the entire Solar System. ...The campfires shown in the first image set were captured by the Extreme Ultraviolet Imager (EUI) from Solar Orbiter's first perihelion, the point in its elliptical orbit closest to the Sun. At that time, the spacecraft was only 77 million km away from the Sun, about half the distance between Earth and the star. "The campfires are little relatives of the solar flares that we can observe from Earth, million or billion times smaller," says David Berghmans of the Royal Observatory of Belgium (ROB), Principal Investigator of the EUI instrument.... "The Sun might look quiet at the first glance, but when we look in detail, we can see those miniature flares everywhere we look."... [https://sci.esa.int/web/solar-orbiter/-/solar-orbiter-s-first-images-reveal-campfires-on-the-sun]  See also July 16 New York Times article: Closest Pictures Ever Taken of Sun Show Tiny Campfire Flares [https://www.nytimes.com/2020/07/16/science/solar-orbiter-sun-images.html]

2020-06-24. A Decade of Sun. By NASA Solar Dynamics Observatory (SDO). Excerpt: YouTube video - As of June 2020, NASA’s Solar Dynamics Observatory — SDO — has now been watching the Sun non-stop for over a full decade. From its orbit in space around the Earth, SDO has gathered 425 million high-resolution images of the Sun, amassing 20 million gigabytes of data over the past 10 years. This information has enabled countless new discoveries about the workings of our closest star and how it influences the solar system. ...While SDO has kept an unblinking eye pointed towards the Sun, there have been a few moments it missed. The dark frames in the video are caused by Earth or the Moon eclipsing SDO as they pass between the spacecraft and the Sun. A longer blackout in 2016 was caused by a temporary issue with the AIA instrument that was successfully resolved after a week. The images where the Sun is off-center were observed when SDO was calibrating its instruments.... [https://www.youtube.com/watch?v=l3QQQu7QLoM]  

2020-04-30. There’s Something Special About the Sun: It’s a Bit Boring. By Adam Mann, The New York Times. Excerpt: The sun, like all stars, is a blazing ball of fusion-powered plasma. From its surface emerge magnetic field lines that can cause dark patches known as sunspots. Turn up the activity of these magnetic whorls, and you get more solar storms flinging deadly charged particles and radiation throughout our solar system. If enough of these punishing waves hit a rocky planet, that planet might end up microwaved into a dreary condition where nothing could live. ...A study released Thursday in the journal Science suggests that our sun is rather tame compared with its stellar siblings, and that hundreds of other sun-like stars in our galaxy have on average five times more magnetic activity than our parent star. ...Some previous studies also implied that the sun was quieter than other similar stars. But competing evidence has also found the sun’s activity level is normal for stars of its size. ...Timo Reinhold, an astrophysicist at the Max Planck Institute for Solar System Research in Göttingen, Germany, and co-author of the paper ...and colleagues looked at data collected by NASA’s retired Kepler space telescope, which continuously monitored approximately 150,000 stars in the Milky Way for four years to find exoplanets, and was capable of observing brightness variations from activity such as the appearance and disappearance of starspots. ...During times of peak magnetic activity, when spots pop out all over the surface, a star will dim. Our sun’s cycle lasts about 11 Earth years. For the sun, this dimming is negligible. Data from the past 140 years indicates that its brightness changes by less than a tenth of a percent over the course of its cycle. But for the stars studied by Kepler, the variability could be up to 12 times that amount.... [https://www.nytimes.com/2020/04/30/science/sun-magnetic-storms.html

2020-01-29. World’s largest solar telescope takes its first shot. 
By Daniel Clery, Science Magazine. Excerpt: This new close-up of the turbulent boiling plasma of the solar surface is the debut image of the largest telescope ever built for staring at the Sun. Sporting a 4-meter-wide mirror—twice the size of any existing solar scope—and a vantage point 3000 meters up on the summit of Haleakala on the Hawaiian island of Maui—the Daniel K. Inouye Solar Telescope (DKIST) will reveal unprecedented detail of processes that channel energy from the Sun’s interior into its atmosphere, the corona. Researchers hope that by zooming in on cell-like structures like those shown above—each about the size of Texas—they can learn what causes the Sun to launch powerful flares out into space, potentially causing damage to Earth’s satellites, power grids, and communications. Such information could help scientists give warnings of such events days rather than minutes ahead. DKIST researchers also hope to finally resolve nagging solar mysteries such as: Why is the corona—at more than 1 million degrees C—so much hotter than the Sun’s surface, and what launches the solar wind out into space? .... [https://www.sciencemag.org/news/2020/01/world-s-largest-solar-telescope-takes-its-first-shot] 

2019-12-04. Parker probe traces solar wind to its source on sun’s surface. By Robert Sanders, UC Berkeley News.

2017-07-31. The Eclipse That Revealed the Universe. By Dennis Overbye, The New York Times. 

2017-07-14. Unlocking Mysteries in the Sun’s 11-Year Cycle. By Nicholas St. Fleur. 

2017-06-23. Solving the Scorching Mystery of the Sun’s Erupting Plasma Jets. By Nicholas St. Fleur, The New York Times. 

2016-12-01. Four New Names Officially Added to the Periodic Table of Elements. By Nicholas St. Fleur, The New York Times. 

2015-10-07. Physics Nobel Winners Also Solved Solar Mystery. By JoAnna Wendel, Earth & Space Science News.

2015-06-17. Traces of Earliest Stars That Enriched Cosmos Are Spied. By Dennis Overbye, New York Times.

2015-05-03. Halley's Eclipse: a coup for Newtonian prediction and the selling of science. By Rebekah Higgit, The Guardian.

2014-09-01. Research Aimed at the Heart of the Sun.  Excerpt: With the aid of a powerful instrument, researchers have detected subatomic particles produced by fusion reactions at the very core of the sun. The particles are neutrinos, and the ones detected in this study are low in energy but abundant in number, said Andrea P. Pocar, a physicist at the University of Massachusetts, Amherst. The neutrinos are formed by a fusion reaction between two protons at the core of the sun; they travel to Earth in just eight minutes.... “Previous experiments had measured neutrinos from the sun, but those neutrinos are present in very low numbers,” Dr. Pocar said. “These make up about 90 percent of the total neutrinos from the sun.” Dr. Pocar and his colleagues, a group of more than 90 physicists from around the world, published their findings in the current issue of the journal Nature. They relied on the Borexino detector, an instrument located deep beneath Italy’s Apennine Mountains that is sensitive enough to detect the low-energy particles.... http://www.nytimes.com/2014/09/02/science/research-aimed-at-the-heart-of-the-sun.html. By Sindya N. Bhanoo, The New York Times.

19 August 2011. Stanford scientists find way to predict sunspots. By David Perlman, San Francisco Chronicle. Excerpt: Stanford physicists probing the sun's deep interior have predicted the emergence of sunspots on the surface a full two days before they appear, providing the first early warning of the violent solar storms that can endanger astronauts in space, disrupt electric power grids on Earth, and plunge cities into darkness…
Solar physicist David Hathaway at NASA's Marshall Space Center in Huntsville, Ala., called the Stanford group's predictions "an important result."
"It's long been our hope to see the storms of sunspots before they show up," Hathaway said. The experiments that led to today's report in the Journal Science were conducted by Stathis Ilonidis, a graduate student in physics at Stanford, and his colleagues…

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?

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. See http://www.nasa.gov/stereo 

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."