WHAT’S THE DIFFERENCE BETWEEN COMETS, ASTEROIDS AND METEORS?
We’ve all probably heard of comets, meteors and asteroids. We think of them as chunks of space rock or ice that traverse our Solar System and occasionally hit Earth and other planets, but how do they differ from each other and what can we learn from them?
Asteroids are lumps of rock left over from the formation of the Solar System 4.6 billion years ago. They orbit the Sun with many of them residing in a part of the Solar System called the asteroid belt, a torus-shaped field of floating interstellar rocks between Mars and Jupiter. They range in size from Vesta – the largest at about 329 miles in diameter – to ones that are less than ten metres across.
Sometimes one asteroid can hit another, with a small piece breaking off and becoming something called a meteoroid. When such a meteoroid hits Earth’s atmosphere it begins to burn up, creating a fire trail through the sky which is visible with the naked eye – a meteor. But sometimes they aren’t completely vaporised in the atmosphere and hit Earth, when this happens they’re called meteorites.
Comets are made of a mix of ice, rock and gas. They’re also leftovers from the formation of the Solar System and orbit the Sun. But because of the way they’re made, as they get closer their ice and dust begin to melt which gives it a beautiful ‘tail’. These tails can stretch for millions of miles and are sometimes visible from Earth.