Asteroider consists mainly of metals and stones. Only in ours[–>[–>solsystem there are millions of asteroids, and their sizes vary wildly. The smallest asteroids measure one meter in diameter, while the largest can measure several hundred kilometers. Scientists once believed that asteroids were fragments from shattered planets. Today, it is widely agreed that they originate from the solar system’s infancy, and that Jupiter’s gravity prevented them from merging into a planet.
Meteorer are fragments broken off when asteroids or comets collide. They measure anywhere from 20 micrometers to one meter in diameter. Meteors often burn up when they enter the Earth’s atmosphere. Those meteors that do not burn up and land on the earth’s surface are called meteorites.
Kometer consists – in contrast to asteroids – mainly of ice, CO2 and other frozen gases. Normally, comets are almost impossible to see due to their small size, but when they approach the inner solar system, the ice and gases can form a characteristic tail – a so-called comet tail. The tail forms when the sun heats up the comet’s surface. Then water and gas are released, which creates the effect of a tail at the back of the comet.
