Physicists and astronomers study the ways in which various forms of matter and energy interact. Theoretical physicists and astronomers may study the nature of time or the origin of the universe. Some physicists design and perform experiments with sophisticated equipment such as particle accelerators, electron microscopes, and lasers.
China has been successful in launching its first X-ray space telescope for studying the black holes, gamma ray bursts, and pulsars.
In astronomy, the geocentric model (also known as geocentrism, or the Ptolemaic system) is a superseded description of the universe with Earth at the centre. Under the geocentric model, the Sun, Moon, stars, and planets all circled Earth.