Geoscience
Meteors and meteorites
Iron meteorite, 16.5 kg. Tieraco Creek, Northern Territory. Photo: K Lowe © Australian Museum.
Solid pieces of extraterrestrial debris (meteoroids) can stray from their orbits in outer space and be captured by Earth's gravity. Most come from the asteroid belt lying between the orbits of Mars and Jupiter, about 400 million km from the Sun. Bodies within this belt range from dust particles up to small planets hundreds of kilometres in diameter (asteroids). Rarely they may come from the Moon, Mars or comets.
The main difference between meteors and meteorites:
- meteors: the initial solid particle (meteoroid) can be too small to survive its flight through Earth's atmosphere and burns up completely when heated by friction with air, to give a momentary streak of light
- meteorites: larger meteoroids survive their fiery ordeal and land on the Earth's surface. Very small meteoroids may remain intact or melt to form glassy droplets which rain down on Earth's surface as micrometeorites. Tiny dust particles get rid of heat as quickly as it is applied, so do not burn up and fall gently on the Earth's surface.
