It's hot...super hot - Finding answers around the Sun
From NSF -- Astronomers have collectively puzzled over two working theories for a conundrum involving the sun that have been discussed in Astronomy 101 classes for decades: Why is the sun's corona (the atmosphere beyond the sun) so hot? The sun's core is a searing 15 million degrees Kelvin, but by the time that heat reaches the sun's surface, it cools off to a mere 6,000 degrees, only to again heat up to more than a million degrees in the corona.
Two National Science Foundation- (NSF) funded researchers at Columbia University recently published what they believe is the solution, and it has to do with magnetic waves known as Alfven waves.
For a summary of the discovery, visit the NSF Discoveries website.