Hotspots in fountains on the Sun’s surface help explain coronal heating mystery
Among the many constantly moving, appearing, disappearing and generally explosive events in the sun’s atmosphere, there exist giant plumes of gas — as wide as a state and as long as Earth — that zoom up from the sun’s surface at 150,000 mph. Known as spicules, these are one of several phenomena known to transfer energy and heat throughout the sun’s magnetic atmosphere, or corona.
Thanks to NASA’s Solar Dynamics Observatory (SDO) and the Japanese satellite Hinode, these spicules have recently been imaged and measured better than ever before, showing them to contain hotter gas than previously observed. Thus, they may perhaps play a key role in helping to heat the sun’s corona to a staggering million degrees or more. (A number made more surprising since the sun’s surface itself is only about 10,000 °F.)
The traditional view is that all heating happens higher up in the corona. The suggestion in this research is that cool gas is ejected from the sun’s surface in spicules and gets heated on its way to the corona. This doesn’t mean the old view has been completely overturned, but this is a strong suggestion that part of the spicule material gets heated to very high temperatures and provides some coronal heating.
Image: Spicules on the sun, as observed by the Solar Dynamics Observatory. These bursts of gas jet off the surface of the sun at 150,000 miles per hour and contain gas that reaches temperatures over a million degrees.
• Source: Full story at NASA
