Sunspot Loops in Ultraviolet . ... Credit Copyright: TRACE Project , NASA Explanation: It was a quiet day on the Sun . ... Shown in ultraviolet light , the relatively cool dark regions have temperatures of thousands of degrees Celsius . Large sunspot group AR 9169 is visible as the bright area near the horizon. The bright glowing gas flowing around the sunspots has a temperature of over one million degrees Celsius . ... NASA Web Site Statements, Warnings, and Disclaimers . ...