Sunday, October 26, 2014
A Dark Spot on the Sun Seething with Energy
Many of you in North America who saw the partial eclipse of the Sun last Thursday may have noticed a nice dark spot under the eclipsed part of the Sun. The full "active region" (that the visible spot is part of) is bigger in area than the giant planet Jupiter and has become the largest such feature on the Sun in 24 years.
With the kind permission of the photographers, I am posting here a beautiful close-up of the area, by Randall Shivak and Alan Friedman. Look how wonderfully complex it is!
The darker regions on the Sun are called sunspots; they look darker because they are slightly cooler than the Sun's visible surface layer. The Sun is made entirely of seething hot gas, where the atoms are so hot, they easily lose their electrons. This makes our Sun highly magnetic, and as it spins, its magnetic zones get all twisted up. It's those twisted regions that appear to us as active regions.
Astronomers have already observed some "flares" -- sudden releases of extra energy -- from this region, but they haven't been sent in our direction in space. The region is now facing the Earth as our Sun does its slow rotation. So we may get some extra high -energy particles coming our way in days to come (or not -- weather from the Sun is as hard to predict as weather on Earth.)
For a nice movie of this region "crackling" with magnetic energy as the Sun rotates, see: http://apod.nasa.gov/apod/ap141022.html