Meteoroids, Meteorites and Meteor
(From Kids InfoBits Presents: Astronomy. Gale, 2009.)
Meteors are sometimes called shooting stars, but they really are not stars at all. They are the bright lights coming from pieces of rock that broke off of planets or comets. Some are even dust from comets. A collection of meteors is referred to as a meteor shower. The Lyrid meteor shower occurs each April.
Meteors come in different colors, sizes, and brightness. Their glow is what makes them show up in the night sky.
Meteoroids, Meteorites, and Meteors
Many people mix up the words meteoroid, meteorite and meteor. These words are similar, but they mean different things. A meteoroid is a piece of rock moving through space. A meteoroid that falls to the earth's surface is called a meteorite. A meteor is the bright streak of light a meteoroid makes in the sky as it falls.
Size, Speed, and Light
Most meteoroids are the size of a tennis ball. Some are as tiny as a grain of salt and are called interplanetary dust. Really large meteoroids are called asteroids.
A meteoroid travels 5,000 times faster than a car zipping down a highway. Because it is moving so fast, the meteoroid compresses the air in front of it. It pushes even harder on the air than a moving boat does on the water in front of it. As a boat moves through water, it leaves a wake behind it. Meteoroids do the same with the air.
The force of a meteoroid pushing hard against the air is called ram pressure. This action heats the air around the meteoroid. The heated air makes the meteoroid burn hot. Meteoroids can be as hot as 3,000 degrees Fahrenheit (1,649 degrees Celsius). Because of this great heat, most meteoroids burn up as they fall through the atmosphere.
Scientists say that as much as 1,000 to 10,000 tons of meteoritic bits fall to Earth every day. If all these bits were piled in one place, they would weigh as much as 200 to 2,000 elephants. Luckily, most of the pieces that fall are as tiny as bits of dust. And since they are so light, they float gently through the air.