Mystery (Partially) Solved? 'Heat Bombs' Warm Sun's Outer Atmosphere

While the sun's visible surface is about 10,000 degrees Fahrenheit (5,538 degrees Celsius), its upper atmosphere, known as the corona, has temperatures in the millions of degrees. The satellite recently saw evidence of "heat bombs," which occur when magnetic fields cross in the corona and realign, much like the process that causes solar flares.