Astronomy Picture of the Day

  The above image shows, however, that even during off days the Sun's surface is a busy place.   Sunspot Loops in Ultraviolet Credit: TRACE Project, NASA Explanation: It was a quiet day on the Sun. The above image shows, however, that even during off days the Sun's surface is a busy place. Shown in ultraviolet light, the relatively cool dark regions have temperatures of thousands of degrees Celsius. Large sunspot group AR 9169 from the last solar cycle is visible as ... Full Story