What's in our Solar System?

Credit: The International Astronomical Union/Martin Kornmesser

Orbiting the Sun are eight major planets - with their moons and rings - and countless smaller bodies: dwarf planets, asteroids and comets. Together, they make up our Solar System.

Much ado about nothing: Comets may look impressive, but their long tails are very tenuous, and their icy nuclei are only a few kilometres across. This photo shows Comet Hale-Bopp.
Credit: ESO/E. Slawik

Our Solar System is basically one star (the Sun) and a tiny amount of debris, less than 0.2 % of the total mass, left over from the Sun’s birth. Four small, rocky worlds, including our home planet the Earth, orbit the Sun within 250 million kilometres. Four larger planets – the gas giants – are spread out over distances between 750 and 4500 million kilometres. Rocky asteroids orbit between Mars and Jupiter, icy mini-worlds can be found beyond Neptune, and smaller comets traverse the system on highly elongated paths.

Minor planet: At some 100 kilometres across, Lutetia is one of the largest asteroids in the belt between the orbits of Mars and Jupiter.

You probably know the eight planets by heart: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. But do you know about the other objects in the Solar System?