As a science, astronomy is based primarily on observations. Unlike physicists, astronomers are unable to make experiments. Virtually all information about celestial bodies brings us to the electromagnetic radiation. Only in the last forty years separate worlds began to study directly: to probe the atmosphere of planets, to study the lunar and Martian soil. Astronomy is closely related to other sciences, primarily physics and mathematics, whose methods are widely used in it. But astronomy is an indispensable testing ground, which tested many of the physical theory. Space - the only place where the substance exists at temperatures of hundreds of millions of degrees, and almost at absolute zero, the vacuum in vacuum and in neutron stars. In recent years, the achievement of astronomy began to be used in geology and biology, geography and history. more info >>