Blue sun

NASA Heliophysics News from 3D Sun iPhone app The Emerald Sun. In this high-resolution ultraviolet image, green and blue colors trace scorching hot million-degree gas. The Emerald Sun. In this high-resolution extreme ultraviolet image recorded by SDO on April 9, 2010, green and blue colors trace gas temperatures in the range 1 to 1.5 million K. Pinch the image with two fingers to make it expand. Large image