ABSTRACT
The solar system is a gravitationally bound system consisting of the Sun, planets and their moons, smaller objects such as asteroids, minor planets, and comets, the interplanetary medium, and the hypothetical Oort cloud. It is a planar system with the orbits of all planets lying roughly in the same plane. The motion of each planet is dominated by the gravitational pull of the Sun. The effect of all other objects is relatively small and can be neglected to a good approximation. The Sun gives dominant contribution, about 99.86%, to the mass of the solar system. Its size, however, is much smaller in comparison to the radius of the solar system. The outermost planet, Neptune, is at a distance of about 30 AU, which is roughly 6,000 times the solar radius. Due to these large distances, the angular momentum of the solar system is dominated by the planets and not the Sun. The solar system actually extends to much larger distances. Beyond Neptune lies the Kuiper belt, at distance between 30 AU and 55 AU. It consists of a large number of small objects and its shape roughly resembles a donut. At much larger distances, on the order of 5,000 AU to 100,000 AU, lies the hypothetical Oort cloud. It is believed to be a spherically symmetric region, containing a huge number of small objects. The comets originate in the Kuiper belt and the Oort cloud.
