Chandra image of the over three-hundred-year-old supernova remnant, Cas A. The colors are “true” in that the higher energy X-rays are shown in blue and the lower energy X-rays in red. A point-like object near the center is not an ordinary star. It may be a neutron star remnant of a core collapse supernova explosion [3]. The size of the region is 7.3 × 6.4 arc minutes.