Asteroids - Introduction
- General Information
- Asteroids are rocky and metallic objects that orbit the Sun which are too
small to be considered planets.
- They are known as minor planets
- Range in size from diameters of 1000 km down to pebble size.
- 16 asteroids are 240 km or bigger.
- Most exist in a main belt which lies between Mars and Jupiter.
- Most asteroids follow a slightly elliptical, stable orbit which takes them
around the Sun every 3-6 years.
- The total mass of all the asteroids put together would form an object about
half the diameter of our moon.
- Asteroid: Rocky or metallic object which is too small to be a planet and is not
- Meteoroid: A piece of interstellar matter which is too small to be an asteroid
and is on a collision course with Earth.
- Meteorite: A meteoroid that makes it through the Earth's atmosphere without
burning up, and actually strikes the Earth's surface.
- Micrometeoroid: Particles or cosmic dust grains which are even smaller than
- Asteroids are material left over from the formation of the solar system.
- Much of our understanding about asteroids comes from examining meteorites.
- One theory suggests that they are the remains of a planet which was destroyed
in a massive collision.
- Another theory suggests that they are material which never coalesced into a planet,
perhaps due to Jupiter's strong gravity.
- Scientists are very interested in asteroids because they consist of material from the
very early solar system.
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