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Meteors are the streaks of light seen when meteoroids enter the Earth’s atmosphere at high speed and burn up. Several times a year it is possible to see meteor showers. This is when the Earth passes through the debris left by a comet. These showers can vary in strength, with some giving a few meteors an hour, but others producing a spectacular show of a couple every second. The name of the meteor shower indicates which part of the sky it appears to come from, for example, the Perseid shower appears to originate in the constellation of Perseus.
| Shower | Date of Maximum |
Approximate Hourly Rate |
|---|---|---|
| Quadrantids | Jan 3/4 | 100 |
| Lyrids | April 21 | 10 |
| Eta Aquarids | May 5 | 35 |
| Delta Aquarids (south) (north) |
July 29 Aug 6 |
25 10 |
| Perseids | Aug 12 | 80 |
| Orionids | Oct 20-22 | 25 |
| Taurids | Nov 5 | 10 |
| Leonids | Nov 17 | 10 |
| Geminids | Dec 13 | 100 |
| Ursids | Dec 23 | 10 |
Meteorites are meteors that reach the ground. They are usually made of rock or iron. About 40-50 tonnes of debris enters the top of the Earth’s atmosphere every day, but atmospheric friction
causes it to burn up so that only about a tonne reaches the ground. When a particularly large meteorite strikes the ground it will form a crater. An example of this is Meteor Crater in Arizona. The crater itself measures 1.2 km in diameter and 175m in depth. It was created 50 000 years ago by a meteorite only about 50m across.
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Authors: Carolyn Brinkworth and Claire Thomas
Last updated: July 2001