An unusually active sunspot region crossing the Sun. The region, several times larger than the Earth, glows to incandescence with super-hot hydrogen as towering prominences light up along the limb.
Usage: This photograph was used in the Stephen Hawking book “George and the Unbreakable Code”, the Astronomy Picture Of the Day (APOD) for May 2, 2006 and as the definition of a solar flare in The American Heritage Dictionary.
