Asteroids
When asteroids enter the a planet's atmosphere, they are called meteors. Most asteroids falling on Earth are very small and usually not bigger than a meter in diameter. The small asteroids are destroyed before they reach the ground, giving birth to the beautiful phenomena of meteors. The atmosphere plays a very important role, acting as a real shield, to protect life & people living on earth.
 |
The picture shows the
distribution of the 136 meteoric explosions in the upper atmosphere recorded by
the USA system of satellites between 1975 and 1992. The total number of major meteoric events during this period was estimated to be 10 times greater. For example, there are millions of interstellar dust particles colliding with the earth atmosphere every year. (courtesy of the US Air Force) |
Most meteors burn up in the our atmosphere as they fall harmless to earth. There are pictures of the four types of meteors. The composition of asteroids has been determined based upon analyzing various meteors.
 |
Several hundred thousand asteroids have been discovered.
Thousands more are being discovered each year with most of the asteroids
located between Mars & Jupiter.
Asteroids, coming close to earth over the next one hundred years, are called near earth objects. There are no known asteroids on a collision course with the Earth and the probability is essentially zero. The picture on the left shows what asteroid look like. |
Science New Links provides more detailed information on asteroids and meteors.