skyeye
Dark Sun Sizzling

Is this our Sun? Yes. Even on a normal day, our Sun is sizzling ball
of seething hot gas. Unpredictably, regions of strong and tangled magnetic
fields arise, causing sunspots and bright active regions. The Sun's surface
bubbles as hot hydrogen gas streams along looping magnetic fields. These active
regions channel gas along magnetic loops, usually falling back but sometimes
escaping into the solar corona or out into space as the solar wind. Pictured
above is our Sun in three colors of ultraviolet light. Since only active regions
emit significant amounts of energetic ultraviolet light, most of the Sun appears
dark. The colorful portions glow spectacularly, pinpointing the Sun's hottest and
most violent regions. Although the Sun is constantly changing, the rate of visible
light it emits has been relatively stable over the past five billion years,
allowing life to emerge on Earth.