Meteors

meteor

A meteor is commonly called a shooting star or falling star because this is what it resembles, but both of these terms are incorrect. What you are actually seeing when you view something that looks like a big fireball shooting through the sky is a meteor. A meteor is a solid object that is entering Earth's atmosphere.

As the solid object enters Earth's atmosphere it causes friction between the object and the surrounding air molecules. This causes the air molecules to heat up or become excited. The bright flash of light is a result of the air molecules returning back to their normal state.

Some Terminology

You already know what a meteor is, but people often get the following two terms mixed up with meteor:

  • Meteoroid - A solid object in space that is orbiting the sun.
  • Meteorite - A solid object that makes it all of the way to Earth's surface.

Sometimes meteoroids become meteors by leaving their orbit and entering Earth's atmosphere. Often the cause of this is that the meteoroid runs into something in space that knocks it out of orbit.

Comet or Meteor?

When viewing the night sky you can easily tell the difference between a meteor and a comet because a comet remains in view much longer than a meteor. A comet may remain visible for weeks, but a meteor is a flash of light across the sky that disappears very quickly.

What are Meteors Made From?

Meteors are derived from either meteoroids, asteroids, or cometary fragments. The distinction between asteroids and meteoroids is determined by their size. Asteroids are much larger than meteoroids. Meteoroids are usually less than 100 meters in diameter and are more commonly the cause of a meteor. Both meteoroids and asteroids are made from rocky chunks of interplanetary debris that usually consist of a combination of iron and nickel, iron and stone, or just stone.

Often the meteor will disintegrate on its way down to Earth's surface. If the meteor makes it all of the way to Earth's surface it is called a meteorite. Here is how scientists classify meteorites:

  • Iron
  • Stony-Iron
  • Stony

Scientists may be intelligent, but not necessarily always creative. Obviously meteorites are categorized by the substance they consist of.

Contrary to popular belief, meteorites that make it to Earth's surface are probably not hot. In fact, they may be cold. This is because meteoroids in space are cold and only the surface of the meteorite heats up as it moves through the atmosphere. The meteorite core remains cold.

The largest meteorite to hit the Earth's surface landed in Africa and weighed 66 tons. Most smaller meteors disintegrate before they get through Earth's atmosphere. In contrast, our moon gets hit by meteorites often. This is because the moon doesn't have an atmosphere like Earth does and so there is nothing to prevent a meteor from reaching its surface. This is why the moon has so many craters.

Meteor showers are generally caused by cometary fragments. We usually see a meteor shower when Earth passes through lots of meteoroids that were left behind from a comet's orbit.

Photo of Meteor: © The Corel Corporation - may not be copied.