Overview
Our Solar System consists of the Sun and everything bound to it by gravity. It formed about 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud.
Inner Planets
The four inner planets (Mercury, Venus, Earth, and Mars) are terrestrial planets primarily composed of rock and metal. They are smaller and denser than the outer planets.
Outer Planets
The outer planets include two gas giants (Jupiter and Saturn) composed mainly of hydrogen and helium, and two ice giants (Uranus and Neptune) composed mostly of volatiles like water, ammonia, and methane.
Other Objects
The Solar System includes dwarf planets like Pluto, dozens of moons, and millions of asteroids, comets, and meteoroids. Most of the system's mass is in the Sun, with Jupiter containing the majority of the remaining mass.