Asteroids are tiny rocky planets that orbit the Sun. They can be as small as 1 kilometer(km) across or as large as 700 km. There are thousands of asteroids in our Solar System. Most of them can be found in an asteroid belt between Mars and Jupiter.

    Asteroids whose orbits cross the Earth’s orbit are called Apollo asteroids. There are so many asteroids that scientists just identify them with numbers or they may name them after people.

    Meteors or “shooting stars” are space particles that have either been left behind by comets, or broken off from asteroids. Meteors orbiting the Sun are called meteoroids and are made of rocks and chunks of metal like iron and nickel.

    A falling meteor is spectacular to watch as it leaves a bright trail of light across the sky called a fireball.

     Sometimes the Earth passes through a stream of meteors called a meteor shower. Meteor showers can be seen in the sky almost on the same date each year. The best ones occur around January 3, August 12, and December 14.

    Millions of meteoroids enter the Earth’s atmosphere, but most burn up before they reach the surface of the Earth. Sometimes, however, a large meteor does not completely burn, and what is left crashes to Earth. A meteoroid that lands on Earth is called a meteorite.

    Large meteorites have landed in South Africa, Antarctica, Russia, Canada and many other places. Because the small ones may look like dark colored Earth rocks, many meteorites land on Earth undetected.

    The larger meteorites, however, leave craters in the Earth like the Barringer Meteor Crater in Arizona. This crater was created by a meteorite that fell to Earth almost 40,000 years ago.

    Some scientists believe that dinosaurs and other life forms died when a large meteor crashed to Earth creating a dust cover around the Earth that blocked out the Sun.