Image: The Aug. 9 X-class solar flare erupts
Living With a Star
Aug. 9, 2011 --
In April 2010, NASA's Solar Dynamics Observatory (SDO) opened its eyes for the first time. Since then, the spacecraft has revolutionized our understanding of the star on our cosmic doorstep. Through the SDO's high definition view of the sun, solar mysteries have been solved and new mysteries have been revealed for the first time. Today, as the sun ramps up in activity -- fast approaching solar maximum, predicted to occur in 2013 -- our nearest star has generated the largest explosive event since 2006: an X-class solar flare. The "X7" flare reverberated through the inner solar system, causing a storm of high-energy protons to buzz around our planet, drenching our upper atmosphere in X-rays. Even though the flare was directed away from Earth, its impact was felt. To commemorate the most energetic flare in five years, Discovery News has teamed up with Camilla Corona SDO (the SDO's famous mission mascot) to collect some of the SDO's most breathtaking photographs of the past few months.
First Light On April 21, 2010, the first photographs from the SDO were received. One of the iconic first views of the high-definition sun was that of a rising prominence; an arc of solar plasma slowly rising into the sun's hot corona.
Valentines Flare Late on Feb. 14, 2011, while the world celebrated the final hours of Valentines Day, the sun let rip with Solar Cycle 24's first X-class solar flare. At the time, the X2 blast was the biggest since the previous cycle's X9 flare in Dec. 2006.
View Blocked The nature of the SDO's orbit around the Earth means it rarely has its view of the sun interrupted. But occasionally, an unavoidable celestial event causes a break in solar observing service. This partial solar eclipse, as witnessed on July 10, 2010, was the first eclipse experienced by the SDO. Note the edges of the moon's shadow across the sun's disk -- lunar mountains and valleys are silhouetted.
Prominence Rains Down On Feb. 24, 2011, the SDO zoomed in on an M-class flare (a "medium-sized" eruption) to see a vast amount of solar plasma rain back down toward the solar "surface" -- the photosphere.
Comet Death Comets often take a death-plunge deep into the solar corona, ultimately getting snuffed out of existence by the searing heat of the sun. Now we have an incredibly powerful solar observatory looking deep into the corona, we can see these "dirty snowballs" pay the ultimate price.
Coronal Rain What goes on deep in the sun's corona often stays deep in the sun's corona. Until now. With the help of the SDO, solar scientists are able to spot tiny dynamic features in the lowermost regions of the sun's atmosphere. One phenomenon characterized by the SDO is "coronal rain" -- blobs of hot solar plasma "raining" down onto the solar surface. Oh, and that black filament thing sitting in the center of the image? That's just a piece of fluff that stowed away with the SDO before it was launched, forever stuck in the telescope's lens.
Sunspots Sunspots are blemishes seen on the sun's surface. They are the side effect of the tangled magnetic fields from the solar interior getting forced through the sun's photosphere. As the hotter plasma above the photosphere is pushed away, the cooler interior is exposed, producing a dark spot. Sunspots are immensely detailed and the SDO can peer right into them, showing intricate plasma flows and magnetic structures. The pixelated textures surrounding this sunspot group is known as granulation -- regions where plasma up-wells from the solar interior and sinks again, like the convection of boiling water in a saucepan.
Twisting Prominence On March 19, 2011, a beautiful, twisting prominence erupted into space from the solar limb. The incredible detail of the hot solar plasma wrapped in a coiled magnetic field was easily captured as the arc expanded.
An Epic Event On June 7, 2011, something happened to the sun. This "something" baffled solar physicists. This "something" had never been seen before. During a "medium" M-class solar flare, a huge quantity of solar material was kicked into space, but most couldn't escape the sun's gravitational pull. The result was a dense, dark, "giant clod of dirt" that obscured the solar disk. A coronal mass ejection (CME) was also generated, but this fascinating eruption was notable for the strangeness of the imagery captured by the SDO.
The sun has unleashed the biggest solar flare of the year, quickly followed by an Earth-directed coronal mass ejection (CME). Both phenomena have the potential to impact communications and electronics on Earth and in orbit.
Although the sun is currently experiencing “solar maximum” — the culmination of its approximate 11-year cycle — scientists have noted that this particular maximum is a lot quieter than predicted. At this time, the sun should be bubbling with violent active regions, exhibiting sunspots, popping off flares and ejecting CMEs. But so far, the sun seems to be taking it relatively easy.
That was before today, however.
This morning (at 0716 UT), active region (AR) 1719 erupted with an M-class flare. With a rating of M6.5, this event is the most energetic flare of 2013 (although it’s a lot less impressive than 2012′s X-class fireworks). What’s more, the site of the explosion unleashed a CME in our direction.
A CME is a magnetic ‘bubble’ containing high-energy solar particles. When the CME hits Earth’s global magnetic field, it may align just right to generate a geomagnetic storm. Should this happen, we’ll be able to measure the extreme magnetic distortion of the magnetosphere and bright aurorae at high latitudes may result. Aurorae are caused when solar particles are injected into the polar regions via the Earth’s magnetic field — the particles then collide with atmospheric gases, generating a beautiful light display.
This morning’s CME was clocked traveling at a breakneck speed of 600 miles per second — at that rate it should hit Earth in the early hours of Saturday morning (April 13).
Shortly after the M-class flare erupted, a weak solar energetic particle (SEP) event was detected. This “radiation storm” was the result of relativistic particles slamming into the Earth’s upper atmosphere originating from the flare site.
The impact of radiation storms and geomagnetic storms do not directly threaten life on Earth, although there can be consequences for our high-tech society. The Earth’s magnetic field and thick atmosphere deflects and mops up the radiation and high-energy particles from the sun, but radiation storms can cause fluctuations in the electron content of the ionosphere, one of the uppermost regions of the atmosphere. This can interfere with planet-wide radio communications. Also, when the CME hits, and if the magnetic conditions are right, vast electrical currents can be induced through the atmosphere, potentially impacting regional electrical grids. Also, satellites are vulnerable in the high-energy space weather environment.
Fortunately, with the help of NASA, the NOAA and other global space weather efforts, we are getting better at predicting the impact of space weather on our planet so we can prepare for the worst case scenario.
Image: NASA’s Solar Dynamics Observatory captured this image of an M6.5 class flare at 3:16 EDT on April 11, 2013. This image shows a combination of light in wavelengths of 131 and 171 Angstroms. Credit: NASA/SDO