2. Black holes
The Chandra X-ray Observatory (CXO), formally recognized as the Advanced X-ray Astrophysics Facility (AXAF), is a space observatory originated about STS-93 by NASA on July 23, 1999. Chandra is susceptible to X-ray origins 100 times heavier than any preceding X-ray telescope, facilitated by the great angular interpretation of its glasses. Since the Earth's environment receives the vast majority of X-rays, they are not detectable from Earth-based telelectroscope; accordingly space-based telescopes are needed to make these observations. This observatory is basically famous for the study of Black holes in the Universe.