X-Ray Moon . ... ROSAT Mission , MPE , ESA Explanation: This x-ray image of the Moon was made by the orbiting ROSAT ( R ntgensatellit ) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky background. The bright lunar hemisphere shines in x-rays because it scatters x-rays emitted by the sun . ... NASA Official: Jay Norris. ...