Asteroids or Minor Planets

On January 1st in 1801, a man named Giuseppe Piazzi found a new object in the sky. It was circling the Sun out beyond the planet Mars. Piazzi thought it might be a comet. Some people thought that it was a new planet. Over the next few years many more objects were seen. All of these were much smaller than a planet. Astronomers new call these objects 'asteroids' or 'minor planets'.

There are thousands of known asteroids in our solar system. They tend to vary in shape and size, ranging from large spheres to smaller slabs and strangely-shaped objects. Some asteroids are big. Most are the size of a boulder. Smaller asteroids form when two big asteroids smash into each other and break up. Astronomers think that there are millions of tiny asteroids scattered in our solar system.

Just like all the planets planets, all asteroids in our solar system also circulate around the Sun in their orbits. Orbit is the path a planet or an asteroid follows to circulate around the Sun. Most asteroids are found farther from the Sun than Earth, between the orbits of Mars and Jupiter. Some, though, come quite close to the Sun.

Scientists are of the view that millions of years ago an asteroid hit Earth and led to the dinosaurs' extinction.