solsystem

Solarsystem is the Sun and all objects bound to it by gravity. The Sun accounts for most of the system’s mass, while the planets, dwarf planets, moons, asteroids, comets, and interplanetary dust orbit it. The system formed about 4.6 billion years ago from the solar nebula, a rotating disk of gas and dust surrounding the young Sun.

Planets in order from the Sun are: Mercury, Venus, Earth, Mars (the terrestrial planets), followed by Jupiter, Saturn, Uranus, Neptune (the gas and ice giants). Between Mars and Jupiter lies the asteroid belt; beyond Neptune lies the Kuiper Belt, a source of many small icy bodies. Far farther, the hypothetical Oort Cloud is thought to surround the system as a distant reservoir of comets. Pluto was once considered a planet but was reclassified as a dwarf planet in 2006. Many planets have numerous moons; some have rings, with Saturn best known for its extensive ring system.

Orbits are generally in roughly the same plane and are prograde. Orbital periods range from 88 days for Mercury to about 165 years for Neptune. The heliosphere, formed by the solar wind, marks the outer boundary where the Sun’s influence gives way to interstellar space.

Exploration by spacecraft—such as Voyager 1 and 2, Galileo, Cassini, and New Horizons—has expanded knowledge of the Solar System, revealing diverse environments from rocky surfaces to giant atmospheres and icy worlds.