Since ancient times, human beings have looked up at the night sky. Comets (彗星) and meteors (流星) flying through the blackness were seen as signs from the gods. They were used to tell the future of human lives.
In 2013, a meteorite shower hit an area in Russia. It injured around 1,200 people. In ancient times, this would have been a strange and terrible experience. Today, thought, science offers simple explanations for the occurrence (事件).
Meteorites are small pieces of debris (碎片) that float around in space. Sometimes, they come near a planet, such as Earth. When they enter our atmosphere, they often heat up and become very bright. This is why they are sometimes called “fireballs”. They are usually made of metals, such as iron (铁), and other minerals (矿物). The Russian meteorites were stony, with iron making up 10 percent of them.
Meteorite showers, such as that in Russia, happen when a large meteor enters the Earth's atmosphere and, due to heat, breaks up into small parts. Most of these are very small — smaller than a grain of sand — and so don't even make it to the ground. But others can cause a lot of damage.
The meteor in Russia weighed 10 tons when it entered our atmosphere, and broke up about 20-30 miles (30-50 km) above ground. The sky was filled with bright lights and loud noises. Many windows were broken. The damage cost Russia around 206 million yuan.
① meteorite showers happen ② it breaks up into small pieces
③ it falls to the ground as whole ④ it seldom causes serious damage
