When the Moon covers the Sun during a total eclipse, a couple of rare sights greet viewers. One is the corona – the Sun’s hot but thin outer atmosphere, which looks like a silvery halo. The other is the short red or pink tendrils known as prominences – eruptions of gas into the corona. They’re actually there all the time, but they’re impossible to see against the brilliance of the Sun’s disk.
Prominences can span many thousands of miles; the largest are about half the size of the Sun itself. They’re actually thousands of degrees cooler than the surface of the Sun. They look bright only when they’re seen against the dark background of space. When they’re seen against the Sun, they form dark streaks.
Prominences are powered by the Sun’s magnetic field. Strands of the field can levitate above the surface. The strands can be filled with plasma – hot gas that has an electric charge.
Some prominences are common around magnetically active regions. They can erupt in minutes, loop into the corona, then collapse within hours.
Others form in regions that are fairly quiet. They can take days to bloom into the corona, then remain visible for weeks or months.
Some prominences don’t stop at the corona. They can send huge clouds of plasma into the solar system. If they hit Earth, these outbursts can trigger brilliant auroras and disrupt technology – prominent impacts from the Sun.
Script by Damond Benningfield