A Filament Across the Sun
Image Credit & Copyright:
Bret Dahl
Is that a cloud hovering over the Sun?
Yes, but it is quite different than a cloud hovering over the Earth.
The long light feature on the left of the
above color-inverted image
is actually a solar filament and is composed of mostly charged
hydrogen gas held aloft by the Sun's
looping magnetic field.
By contrast, clouds over the Earth are usually much
cooler,
composed mostly of tiny water droplets, and are
held aloft
by upward air motions because they are weigh so little.
The above filament was captured on the Sun about two weeks ago near the
active solar region
AR 1535 visible on the
right with dark sunspots.
Filaments typically last for a few days to a week, but a long
filament
like this might hover over the Sun's surface for a month or more.
Some filaments trigger large
Hyder flares
if they suddenly collapse back
onto the Sun.