... CXC , NASA Explanation: Venus , second planet from the Sun, appears above imaged for the first time ever in x-rays (left) by the orbiting Chandra Observatory . ... While the optical image in reflected sunlight is filled and bright at the center, Venus in x-rays is bright around the edge. Venus' x-rays are produced by fluorescence rather than reflection. ... More x-ray emitting material can be seen looking at the edge of the shell, so the edge appears brighter in the x-ray image. ...