Thanks to NASA's Interface Region Imaging Spectrograph (IRIS), which launched last year, we now not only have an unprecedented view of our sun, but also new data that explains many of its mysteries.
On Friday, five scientific groups published papers in the Oct. 17, 2014 issue of Science magazine based on data and images derived from IRIS' instruments.
"This set of research really delivers on the promise of IRIS, which has been looking at a region of the sun with a level of detail that has never been done before," says Bart De Pontieu the IRIS science lead. "The results focus on a lot of things that have been puzzling for a long time and they also offer some complete surprises."
One of those surprises, perhaps the biggest, concerns pockets of heat at about 200,000 degrees Fahrenheit low in the sun's atmosphere. This discovery surprised scientists who never expected that such high temperatures could exist that close to the sun's surface. These "solar bombs" contain a lot of energy that get released in a short amount of time. This changes everything we understand about the sun's atmosphere and "will likely lead to a reassessment of other phenomena in the low solar atmosphere."
IRIS also gave us some unprecedented images of the sun's interface region, an area that sits between the sun's surface and outer atmosphere (also known as the corona). IRIS shows this area having small dynamic loops. Observing and understanding these might explain how this part of the sun gives off energy and light.
The sun also has "mini tornadoes" in its interface region, on a part of it that sits just above the surface. These features move and twist like tornadoes (hence the name). These little tornadoes twist quickly, at about 12 miles per second, and are part of something called Alfven waves, which is part of the sun's magnetic field that carries energy and heat, up to hundreds of thousands of degrees, throughout the sun's atmosphere.
The solar wind has long been a mystery to scientists, who initially thought that it forms gently as solar material associated with areas of magnetic field on the sun's surface evaporates. However, IRIS shows a different picture and it seems that the solar wind is more like high-speed jets, moving a lot faster than previously thought, up to 90 miles per second.
Finally, IRIS data could clear up confusion about what heats up the sun's corona, the area of plasma that surrounds it. After looking over data from IRIS, scientists believe that "nanoflares" are part of this process. These flares are much like the flares we're familiar with, but are much smaller. Although IRIS can't see these small flares directly, scientists found evidence of them at the "footpoints" of loops that extend from the corona.
IRIS is showing that the sun is much more complicated than we once thought. This new information will further inspire scientists to understanding how the interface region feeds into the hotter area above it, not only helping us better understand our sun, but other stars in the Universe.
