Meteors

Meteors are streaks of light (like lightning) flying through space. They usually last only a few seconds and can be seen in the night sky. These are what people sometimes call "shooting stars" or "falling stars", eventhough they aren't stars at all.

Meteors are caused by small pieces of rock, dust or metal entering the atmosphere from space at a very high speeds. They are called meteoroids (like asteroids) when they are still in outer space. They travel at speeds of tens of km/s when they reach Earth's atmosphere. The high pressure that meteoroids experience when they break through Earth's atmosphere shatters them. This transfers energy to atoms & molecules on Earth. They then release energy by glowing, which produces the trail of light we see as meteors.

Most meteoroids are very small. Their sizes range from a grain of sand to pea-sized stones. Almost all on them disappear before they can reach the ground. A larger meteoroid can actually survive to hit the ground, but this happens very rarely. They then create a meteor crater if the explosion of colliding with the ground is big. This explosion usually vaporizes any solid parts left of the meteor after burning through the atmosphere. But sometimes, solid pieces of meteoroid survive & can be found in and around the crater. These little pieces are called meteorites.

Meteors are different from comets. You'll see why in the next post.

Extremely bright meteors are called fireballs. Some fireballs can even be seen at daytime. (O.O) You can see meteors above any planet that has an atmosphere (eg. on Mars). The picture on the left shows the Leonid Meteor Shower in November 1998. It also include a fireball. ^.^

A meteor shower happens when there are many meteors in one night. Sometimes even more than 100 meteors per hour. This happens when Earth crosses the orbit of a comet. Dust and other particles that have been left behind is what we see as meteors.