. The view shows a composite of data from NASA's Chandra X-ray Observatory (blue) and the Hubble Space Telescope. The bright objects in the center of the image are young, massive stars around M33 X-7, and the bright, blue Chandra source is M33 X-7 itself. X-rays from Chandra reveals how long the black hole is eclipsed by the companion star, which indicates the size of the companion. NASA/CXC/CfA/P.Plucinsky et al.