COMETS and Asteroids
Created | Updated May 18, 2007
Halley's comet
Dimensions · 16 x 8 x 8km
Orbital period · 76 years
Next visible from Earth · 2061
Hale-Bopp
Dimensions · 40km
Orbital period · 4026 years
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Asteroids are lumps of rocky debris that float around in the Solar System.
Asteroids range in size from tiny dust particles to huge worlds nearly 1,000 km (600 miles) across.
Most asteroids are oddly shaped. They aren't spherical like planets, because their gravity is too low to pull them into a round form. (This only happens when asteroids are over 250 km in size.)
Smaller ones are angular and shaped like potatoes and peanuts. The oddest looking asteroid so far is called 'Kleopatra', which is like a 220km long dog bone.
Asteroid belt
Thousands of asteroids swarm across the 20 million miles of space between the planets Mars and Jupiter. This 'asteroid belt' marks the junction between the inner and outer Solar System and houses 90 - 95% of all asteroids.
Others orbit close to the Sun and some have been captured by the gravity of planets like Jupiter, Mars and the Earth.
Asteroids with moons
Some asteroids have others revolving around them, just as the Moon revolves around the Earth. Ida, an asteroid about 56km in diameter has its own moon - a tiny body only 1km in size. Other asteroids may well have moons of their own waiting to be found.
Binary asteroids
Some asteroids travel in pairs, spinning around a common centre of gravity. These are called 'binaries'. Astronomers were surprised by this, because they thought their gravity would be too weak to bind them together.
Dimensions · 16 x 8 x 8km
Orbital period · 76 years
Next visible from Earth · 2061
Hale-Bopp
Dimensions · 40km
Orbital period · 4026 years
-----------------------------------------------------------------------
Asteroids are lumps of rocky debris that float around in the Solar System.
Asteroids range in size from tiny dust particles to huge worlds nearly 1,000 km (600 miles) across.
Most asteroids are oddly shaped. They aren't spherical like planets, because their gravity is too low to pull them into a round form. (This only happens when asteroids are over 250 km in size.)
Smaller ones are angular and shaped like potatoes and peanuts. The oddest looking asteroid so far is called 'Kleopatra', which is like a 220km long dog bone.
Asteroid belt
Thousands of asteroids swarm across the 20 million miles of space between the planets Mars and Jupiter. This 'asteroid belt' marks the junction between the inner and outer Solar System and houses 90 - 95% of all asteroids.
Others orbit close to the Sun and some have been captured by the gravity of planets like Jupiter, Mars and the Earth.
Asteroids with moons
Some asteroids have others revolving around them, just as the Moon revolves around the Earth. Ida, an asteroid about 56km in diameter has its own moon - a tiny body only 1km in size. Other asteroids may well have moons of their own waiting to be found.
Binary asteroids
Some asteroids travel in pairs, spinning around a common centre of gravity. These are called 'binaries'. Astronomers were surprised by this, because they thought their gravity would be too weak to bind them together.
