Astronomy
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. The scale of the observable universe is huge and the usual unit of distance – meters and kilometers – are of little use. Instead, they introduced others. Astronomical unit is used in the study of the solar system. Is the size of Earth's orbital semi-major axis: 1 as well.
e. = 149 million kilometers. Larger units length – a light-year and parsec, as well as their derivatives (kiloparsecs, Mpc) – Need to stellar astronomy and cosmology. Light year – distance traveled by light in vacuum during one Earth year. It is about 9,5 1015 m. Parsec is historically linked with the measurement of distances to stars by their parallax and is 1 pc = 3.263 light years = 206 265 as well.
e. = 3,086 1016 m. Astronomy is closely related to other sciences, primarily physics and mathematics, whose methods are widely apply 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. It is no longer necessary to determine the course of the ship by the stars predict flooding of the Nile, or take the time to hourglass: to replace astronomy here come the technical means. But astronomy and space travel is still indispensable in communication systems and television and in the observations of the Earth from space. Astronomy studies the fundamental laws of nature and evolution of our world. Therefore, it is especially great philosophical significance. In fact, it defines the outlook of people.