Classical Astronomy. The Solar System

Abstract

We shall begin our treatment of astronomy with a historical overview of classical astronomy (Sect. 2.1) from ancient times up through the introduction of the heliocentric system by Nicholas Copernicus, Tycho Brahe, Johannes Kepler, Galileo Galilei and their contemporaries, and the founding of celestial mechanics by Isaac Newton at the close of the 17th century. We then turn in Sect. 2.2 to the description of motions on the celestial sphere and the coordinate systems used to describe the positions of objects in the sky. In Sect. 2.3, we treat the motions of the Earth its rotation around its own axis and its revolution around the Sun, which make themselves evident as motions on the celestial sphere; in this section, we also take up the sidereal time scale. Following these preparatory remarks, we make the acquaintance of the objects of our Solar System beginning in Sect. 2.4 with the Moon, its motions, its phases, and with lunar and solar eclipses. In Sect. 2.5, we survey the motions of the planets, the comets, and other bodies in the Solar System, and the methods for determining distances between them. After reviewing the fundamentals of mechanics and the theory of gravitation, we discuss in Sect. 2.6 some of their applications to celestial mechanics and, in Sect. 2.7, to the calculation of the orbits of artificial satellites and space probes. Section 2.7 also contains a brief chronology of space-research missions. Finally, we treat the physical structure of the objects in the Solar System: the planets, their moons, and the asteroids in Sect. 2.8; and the comets, meteors, and meteorites in Sect. 2.9.