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Our Solar System |
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| Home | The Sun | The Planets | Asteroids | Comets | Quiz |
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At the edge of the Solar System, far beyond Neptune and Pluto, orbits a huge number of comets. Comets are frozen bodies, a few kilometres across. Occasionally they are nudged towards the Sun and they start to warm up. The ice then turns to gas and dust is released from the Comet forming a tail. The tail can stretch for 10-100 times the distance from the Earth to the Moon and can look very spectacular. |
| Each year about twenty comets are seen by astronomers. Some of these are new discoveries, while others are known comets returning to the inner Solar System as part of their wide ranging oval orbit of the Sun. The comet with the shortest orbit is Encke, which goes around the Sun in 3.3 Earth years, while other comets take over a million years to go around the Sun. |
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The most famous comet is named after the English astronomer Edmond Halley. He suggested that the comets seen in 1531, 1607 and 1682 were all the same comet and that it was orbiting the Sun every 76 years or so. He predicted that it would return around 1758, and sure enough, it did. The nucleus of halley's comet is about 16km long and 8km wide and is made of ice with a dark, dusty crust. Halley's comet was last visible from Earth in 1986 and is due to appear again around 2062. |
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