What Are Meteors & Asteroids?

Meteors

• A meteor is what's called a shooting star, though it's nothing like a star. It's a solid particle that has been part of a comet or even an asteroid and has found its way into Earth's orbit. Meteors that strike Earth are called meteorites. The Earth commonly passes through a stream of meteors form dead comets and this stream is known as a meteor shower. The Perseid meteor shower occurs in August, the Geminids in December, the Leonids in November. The best way to see a meteor shower is to go to the country on a clear moonless night where there are no street lights around. The meteor shower is named for the constellation it seems to come from. The Leonids radiate out from the constellation Leo, the Perseids from Perseus.

A Fireball

• Once in a while a single meteor will blaze across the sky. It'll be so bright that it might make the news. This meteor's called a fireball. It might leave a trail behind it and if it's low enough it might even make a sound. Meteors glow because of compression, not friction. As they enter the atmosphere at about 45,000 miles an hour the air before them is compressed and the heat of this is transferred to the meteor and makes it glow.

Asteroids

• Asteroids exist in the 342 million mile gap between the orbits of Jupiter and Mars. They're really planetoids, or dwarf planets, and have nothing to do with stars (where the "aster" in their name comes from). They're chunks of rock and some are so tiny they don't even have enough gravity to be spherical. They are what's left over from the birth of the solar system, according to NASA. Only a handful of asteroids have diameters larger than 100 miles. The asteroid belt was hypothesized by Johann Elert Bode (1747-1826) of the Berlin Observatory. Bode's law predicted that a planet should exist between Mars and Jupiter and it turned out there were many dwarf planets there. Other asteroids travel in the same orbit as Jupiter. They're called Trojan asteroids. The leading Trojans go before Jupiter, and the trailing Trojans follow.

Asteroid Names

• Many asteroids have the names of goddesses or nymphs, including Ceres, the largest asteroid. Others are Vesta, Pallas, Hygeia, Psyche. Some asteroids are named after real people, like Neil de Grasse Tyson, Director of the Rose Center at the American Museum of Natural History, the seven astronauts on the Challenger space shuttle, or fictional characters, like Mr. Spock.