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 happen② it breaks up into small pieces

③ it falls to the ground as whole④ it seldom causes serious damage

The Sun offers us light. 【小题1】 It makes things grow. All the living things on the Earth need the Sun. However, how much do you know about the Sun?

The Sun is a huge star. 【小题2】 In the sky, there are thousands of stars like the Sun. They are as large and hot as the Sun. At night, you can see many stars. 【小题3】

Our Earth is cool enough to live on because the hot Sun is so far away. 【小题4】 If a plane flew day and night without stopping, it could take nearly 18 years to get to the Sun. If the Sun were much nearer, our Earth would be too hot to live on. 【小题5】 Aren’t we lucky to be just about the right distance away form the Sun?

How many things can you see in the night sky? A lot! On a clear night you can see the moon, some planets, and thousands of sparking (闪烁的) stars.

You can see even more with a telescope (望远镜). You might see that many stars look larger than others. You might see that some stars that look white are really red or blue. With bigger and bigger telescopes you can see more and more objects in the sky. And you can see those objects in more and more detail.

But scientists believe there are some things in the sky that we will never see. We won’t see them with the biggest telescope in the world on the clearest night of the year. That’s because they’re invisible. They’re the mysterious dead stars called black holes.

You might find it hard to imagine that stars die. After all, our sun is a star. Year after year we see it up in the sky, burning brightly and giving us heat and light. The sun certainly doesn’t seem to be getting old or weak. But stars do burn out and die after billions of years.

As a star’s gases (气体) burn, they give off light and heat. But when the gases run out, the star stops burning and begins to die.

So next time you look up at the night sky, remember: there’s more in the sky than we can see!