NASA Might Have Just Solved One of the Sun's Oldest Mysteries
Why the atmosphere is hotter than the surface.
Pictures beamed back from a NASA space observatory are helping to solve a mystery that’s puzzled scientists since the 1940s: why the outer atmosphere of the Sun, its corona, is hotter than the visible surface.
And we’re not talking about a minor temperature discrepancy, either. At the visible surface of the Sun, you can expect a toasty temperature of about 5,500 degrees Celsius (or 9,932 degrees Fahrenheit), but up in the corona, the temperature is around 200 to 500 times hotter.
Now, based on observations from the IRIS (Interface Region Imaging Spectrograph) mission, NASA researchers think the corona is partly heated by ‘heat bombs’ going off, caused by blasts of energy from magnetic fields criss-crossing and realigning in the corona.