Featured Article Summary #29

The Solar System is made up of the Sun and the objects that orbit it, including eight large planets. The four closest planets to the Sun are Mercury, Venus, Earth, and Mars, and they are made mostly of rock and metal. The other four planets are gas giants, with Jupiter and Saturn being made mostly of hydrogen and helium, and Uranus and Neptune being made mostly of water, ammonia, and methane. The Solar System was formed from a cloud of gas and dust, with the Sun and planets forming as the cloud collapsed. Most of the Solar System's mass is in the Sun, followed by Jupiter. There are also many smaller objects in the Solar System, such as dwarf planets, asteroids, and comets. The Solar System is surrounded by a region called the heliosphere, and beyond that is the Oort cloud. The Solar System is part of the Milky Way galaxy and orbits the Galactic Center. The closest star to the Solar System is Proxima Centauri. The Solar System formed from the collapse of a molecular cloud, with the Sun at its center. Dust and gas in the cloud came together to form the planets, while leftover debris formed regions such as the asteroid belt and Kuiper belt. The Sun will eventually become a red giant and expand, vaporizing Mercury and Venus and rendering Earth uninhabitable. After burning helium, the Sun will shed its outer layers and become a dense white dwarf. The Sun is the center of the Solar System, and its planets follow stable orbits around it. The term "solar" refers to the Sun. The planets and other objects in the Solar System orbit the Sun in the same direction that it is rotating. Most of the planets have their own moons, and the larger moons orbit their planets in the same direction as the planet's rotation. The orbits of objects around the Sun can be described by Kepler's laws of planetary motion, which explain how the distance from the Sun varies over time. The angular momentum of the Solar System is mostly determined by the planets, particularly Jupiter. The Solar System is divided into different regions, including the inner and outer Solar System. The Sun and the four giant planets make up the majority of the Solar System's mass, while the remaining objects make up a very small percentage. The composition of the objects in the Solar System varies based on their distance from the Sun, with those closer to the Sun being composed of elements with high melting points and those farther away being composed of materials with lower melting points. The giant planets and the objects beyond Neptune are primarily composed of gases and ices.