Päikesesüsteemist

The Solar System is the gravitationally bound system of the Sun and the objects that orbit it. It formed around 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system's mass is in the Sun, with the remaining mass distributed among the planets, dwarf planets, and numerous smaller bodies.

The Sun is a G-type main-sequence star. Orbiting the Sun are eight planets, which are divided into two groups: the terrestrial planets and the gas giants. The four inner planets are Mercury, Venus, Earth, and Mars. These are primarily composed of rock and metal and have solid surfaces. The four outer planets are Jupiter, Saturn, Uranus, and Neptune. These are much larger than the terrestrial planets and are composed mainly of gases like hydrogen and helium, with a smaller fraction of heavier elements.

Beyond Neptune lies the Kuiper Belt, a region populated by icy bodies, including dwarf planets like Pluto. Further out is the Oort Cloud, a theoretical spherical cloud of comets that is thought to surround the Solar System. The Solar System also contains many other objects, such as asteroids, comets, and dust. The planets orbit the Sun in elliptical paths, and most of them rotate on their axes.