The Sun Erupts
Credit: Skylab, NASA

Explanation: The Sun is a seething ball of extremely hot gas. Above, the Sun was captured by Skylab in 1973 throwing off one the largest eruptive prominences in recorded history. The Sun has survived for about 5 billion years, and will likely survive for another 5 billion. The Sun is not on fire, will never explode, and a solar flare will never destroy the Earth. The Sun continues to present many unanswered questions.  For example: Why is the Sun's corona so hot? What causes the Sun's unusual magnetic field? Why does the Sun's center emit so few neutrinos?

You can find this photo and other exciting images on the Astronomy Picture of the Day web site. Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.