Though it started small, the eruption stunned scientists by quickly expanding to envelop much of the star. Scientists had previously known that intense solar activity could occur simultaneously on multiple sections of the sun, but the satellite's new capabilities have enabled researchers to see that these events aren't always coincidental. (See more pictures of solar eruptions.)
"We had to be sort of beaten over the head," Alan Title, a physics professor at Stanford University, said earlier this week at an annual meeting of the American Geophysical Union in San Francisco.
—Richard A. Lovett in San Francisco
Image courtesy SDO/NASA
Links between activity on different parts of the sun can be seen in this image, which superimposes a map of the sun's magnetic field on an ultraviolet-light image of the growing August 1 storm. (See more sun pictures.)
Scientists had seen multiple events occurring together in smaller solar storms imaged by the Solar Dynamics Observatory satellite but had been slow to realize how strongly the sun's magnetic field sews everything together.
A still from a NASA video of the August 1 ultraviolet emissions shows temperature variations in the sun's corona, which can range from 1.8 to 4 million°F (1 to 2.2 million°C).
The Solar Dynamics Observatory image reveals links among flare-ups hundreds of thousands of miles apart. "These events happen in step, over the whole diameter of the sun," said Karel Schrijver, a research scientist at the Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto, California.
"So, 1.5 million kilometers [nearly a million miles] of the solar surface is involved at one time."
Coronographs block out the bright disk of the sun, allowing scientists to see the jets, whose energetic particles can make it all the way to Earth and threaten satellites and power grids. (Read "Magnetic-Shield Cracks Found; Big Solar Storms Expected.")
But accurate warnings are still a thing of the future. "We're where weather forecasters were 50 years ago," said Rodney Viereck, chief of the National Oceanic and Atmospheric Administration's space-weather prediction division.
Image courtesy SOHO/NASA
Bright spots and flares can be seen in an August 1 Solar Dynamics Observatory picture taken in ultraviolet light.
These sharper views of the sun's activity may help scientists make better forecasts about sunspot explosions. (See "Sunspot Delay Due to Sluggish Solar 'Jet Stream'?")
"For years solar physicists have been looking for the causes of these explosions in the region that's exploding," said Lockheed Martin's Schrijver. Now scientists are realizing that the triggers may lie far, far away.
That's why scientists need to figure out the processes that store energy in regions where explosions will later occur, he added. "It's like thinking of an avalanche. If there's no snow there, there won't be an avalanche."