On the morning of Nov. 24, China made history by starting the world’s first lunar return mission of the past 44 years. On that day, a Long March 5 rocket was sent into space from the Wenchang Space Launch Center in Hainan province. It’s carrying the Chang’e 5 lunar probe. The mission will last about 23 days, according to the China National Space Administration. The Chang’e 5 mission is special for several reasons.

If someone asks you, “【小题1】” I think you will answer “Blue”. I’m afraid that you will be wrong. 【小题2】 It looks blue because we are looking at the blue sunlight. The sunlight is shining on little bits of dust (灰尘) in the air.

【小题3】 I’m sure that you have asked this question, too. We know that there is air all around the world, but we couldn’t fly very high because as we go high, the air gets thinner. If we go far enough away from the Earth, we find there is no air.

Maybe we can answer some questions now. What is the sky? Where is it? It is all around the world. 【小题4】 In space, there is nothing, but only the Sun, the Moon, the Earth and all the other stars.

What would it be like to live on Mars? The movie The Martian has given us some answers. It follows an astronaut named Mark who is left on Mars for nearly two years. In order to live on Mars, Mark finds a way to grow potatoes in a special room. He wears a spacesuit when he is outside his “home”. However, Mark has to face many difficulties, such as dust storms.

In fact, just like in the movie, walking on the surface of Mars without a suit is a bad idea. Your skin would be peeled away like pieces of burning paper; your blood would turn to steam (水蒸气) and you would die within half a minute. There is bad radiation (辐射) and dust storms. So people would most likely live in underground homes. If technology improves, more people and construction (建筑) materials may be sent to Mars. Only then could people build houses on the surface. And life would start to look like that on Earth. On Mars, people could grow crops, such as wheat and potatoes, in special boxes. They could help make oxygen for humans to breathe like trees do on Earth. But it won’t be an easy thing.

How can people move around Mars? People have suggested cars, bikes, trains, cable cars and planes. However, there are no official plans saying exactly what humans will use.