Key to the Solar System

The Sun is the centre of our Solar System. The mass of the Sun alone is one thousand times the mass of all the rest of the Solar System put together. Why do the planets orbit the Sun? The planets move like this because of the gravitational pull of the Sun (caused by its huge mass). Without this force, the planets would drift off into space.

The Solar System consists of the Sun, planets, moons, asteroids, and comets. Learn about its main components and how they interact in space.

Minor bodies in the Solar System include all objects that are neither planets, dwarf planets, nor moons. These include: Asteroids – Also called "small planets," they primarily reside in the Asteroid Belt between Mars and Jupiter. Meteoroids – Smaller fragments of asteroids or comets that can enter Earth's atmosphere as meteors.

Any natural solar system object other than the Sun, a planet, a dwarf planet, or a moon is called a small body; these include asteroids, meteoroids, and comets. Most of the more than one million asteroids, or minor planets, orbit between Mars and Jupiter in a nearly flat ring called the asteroid belt.

The orbits of planets and other bodies around the Sun are governed by Kepler's laws of planetary motion, which state that each object follows an elliptical path, with the Sun positioned at one of the foci. Most planets in the Solar System have their own moons, forming subordinate systems. Some of these moons are even larger than Mercury.

The Solar System is divided into two groups of planets: All planets and most celestial objects orbit the Sun in the same direction that the Sun rotates— counterclockwise when viewed from the North Pole. Most planets also rotate on their axes in this direction, with the exceptions of Venus and Uranus, which rotate in unique ways.