1 . Mars is the fourth planet from the Sun in the Solar System. Named after the Roman god of war, Mars, it is often described as the “Red Planet”. Mars sometimes can easily be seen from Earth with just our eyes.

Some people believe that humans could live on the planet Mars by the year 2100. At present, however, our space ships are too slow to carry large numbers of passengers to Mars—it would take months. With the development of technology, by the year 2100, the journey might only take about 20 minutes in space ships that travel at the speed of light! However, the space ship would travel so fast that the journey to Mars might be quite uncomfortable. Many people would feel ill.

Humans cannot live without water, oxygen（氧气）or food. So far, nobody knows whether there would be enough water or oxygen on Mars for people there. Besides, scientists are not sure whether plants could grow on Mars. Food would most probably be in the form of pills（药片）and would not be so delicious.

Gravity（重力）could be another problem. The gravity on Mars is only about three-eighths of that on the Earth. People would have to wear shoes that are specially designed to prevent themselves from floating（漂浮）off into space.

Compared with life on the Earth, life on Mars would be better in some ways. People would have more space. They might live in houses with large comfortable rooms. Also, robots would do most of their work so that they could have more time to relax.

There would probably be no schools on Mars. Every student would have a computer at home connected to an interplanetary（星际间的）network. They would study at online schools with “e-teachers”.

Anyhow, so many problems and challenges are there, but one thing is clear: Life on Mars would be interesting as well as challenging.

Scientists think that there has been life on the earth for hundreds of millions of years. However, we have not found life on any other planets yet.

The earth is a planet and it goes around the sun. Seven other planets also go around the sun. None of them has an environment like that of the earth, so scientists do not think they will find life on them. The sun and its planets are called the solar system, and our solar system is a small part of a much larger group of stars and planets, called the Galaxy or the Milky Way. There are billions of stars in the Galaxy, and our sun is only one of them.

Scientists have also discovered many other galaxies in the universe. They are very far away and their light has to travel for many years to reach us. So how large is the universe? 这是无法想象的。

Scientists have sent spaceships to the planet Mars to take photos. They have even sent spaceships to travel outside the solar system. However, no spaceship has travelled far enough to reach other stars in our Galaxy.

Scientists have always asked the questions: with so many stars in the universe, are we alone, or is there life out there in space? Have there been visitors to the earth from other planets? Why has no one communicated with us? We do not know the answers...yet.

3 . As space science develops, man has learned more and more about space. Space is not only amazing but also dangerous. While working in space, spacemen are facing danger as well as success.

Scientists have found out that the radiation（辐射）is the greatest danger to spacemen in space. When spacemen are working in space, they are in danger of the radiation from the sun and other stars, which is bad for their health. The harm of the radiation won’t be found until their children even grandchildren are born. Some special medicine may work a little, but no really effective（有效的）medicine has been found so far.

Space rubbish is also thought to be a great danger to spacemen. It’s reported that there were 9,000 man-made things flying in space. About 30% of these are satellites, 10% are spaceships, and the rest are space rubbish. An explosion（爆炸）in space in 1999 made a cloud of 300,000 fragments, each at least 4mm in size. A small piece of these even knocked on a spaceship window and caused some damage（破坏）.

Scientists are watching and reporting any possible danger all the time. They are working to deal with space rubbish. Although space is really dangerous, it interests many people on the earth. In the near future, it may become possible for people to spend a few days in a space hotel. We may even choose to leave the earth and live in space in a few years. So we should do something to help improve the space environment.

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5 . A group of scientists discovered a gas called phosphine(磷化氢) on Venus(金星). That means there may be living things on the planet, which made many people start to imagine the talk between aliens and humans. A reporter from Washington Post wrote a letter to people of Earth on behalf of(代表) the citizens on Venus.

6 . Like many other countries around the world, China hopes to explore the moon. It has already done so with several probes (探测器) and lunar rover (月球车). But it has even bigger plans to put a man on the moon in the near future.

Yang Liwei, China’s first man in space, said that it will “not take long” for a manned mission (任务) to get official agreement and money support, according to the Xinhua News Agency.

China’s space program is still young compared to those of the United States and Russia. But it has already made great achievements in exploring the moon. Its moon mission began with Chang’e 1, an unmanned orbital (轨道) probe that was sent up in October, 2007. It collected data that was used to create a 3-D map of the moon’s surface.

China achieved another achievement with the Chang’e 3 mission. For this mission, China’s first lunar rover, Yutu, successfully landed on the moon.

For China’s space program, it was another great achievement that Chang’e 4, the second lunar rover successfully landed on the moon’s far side, an area that has not yet been explored, in December, 2018.

China will follow Chang’e 4 with a series of other lunar mission. These missions will include taking lunar soil and rock samples, building “moon base”, and hopefully landing a human on the moon’s surface around 2030, according to Zhao Xiaojin, a senior official at the China Academy of Space Technology.

Last year, when Yang Liwei was asked if he had any plans to visit the moon himself, he replied, “If I am given the chance, no problem!” It is likely that many other Chinese share Yang’s excitement about this new stage of China’s space exploration efforts.

7 . When we talk about the space, we know the universe means the earth, the sun, the moon, the stars and the space between them. Many of the stars are so far away that we cannot see them.

Through our geography lessons, we know the earth goes around the sun, and the moon goes around the earth.

We have day and night because the earth keeps turning all the time. Just because the moon is closer to the earth than the sun, it looks much bigger than the sun. The sun is bright enough to give out very strong light. The moon can’t give any light at all, but it looks quite bright too. Why? In fact, the light from the moon comes from the sun. But in fact the stars are much bigger and brighter than the moon.

There are many other planets in the universe. But of all these planets, only on the earth there are living things. People on the earth have been studying space all the time. They’ve sent spaceships into space many times. On November 3rd and 14th, 2011, Chinese scientists let Shenzhou Ⅷ successfully dock with（对接）the Tiangong I twice. This is one of the greatest events in the history of China’s space.

8 . As space science develops, man has learned more and more about space. Space is not only amazing but also dangerous. While working in space, spacemen are facing danger.

Scientists have found out that radiation (辐射) is the greatest danger to spacemen in space. When spacemen are working in space, they are in danger of radiation from the sun and other stars, which is bad for their health. The damage done by radiation won’t be discovered until their children or even grandchildren are born. Some special medicine may work a little, but no really helpful medicine has been found.

Space junk is also thought to be a great danger to spacemen. It’s reported that there are 9,000 man-made things flying in space. About 30% of these are man-made satellites (卫星), 10% are spaceships, and the rest are space junk. An explosion (爆炸) in 1999 made a cloud of 300,000 fragments , each at least 4mm in size, and even a small piece of these knocked against a spaceship window and did some damage. Scientists are watching and reporting any possible danger all the time. They are working on helpful ways to deal with space junk.

Although space is really dangerous, it interests everyone on the earth. In the near future, it may become usual for people to spend a few days in a space hotel. We may even choose to leave the earth and live in space in a few years. So we should care for space and do something to help improve the space environment.

10 . Vicuna, a small town in the north of Chile, is a great place for watching stars all year round. Although it is near the sea, the cold, wet air from the coast does not bring clouds. Instead, dry winds from the desert keep the clouds away at night. In fact, the sky is so clear in Vicuna that it is possible to see many stars that can be seen only with advanced(先进的) instruments in other parts of the world.

In Vicuna, distant(遥远的) star systems such as Magellanic Clouds can be seen without the help of an instrument. That is why the town was chosen as the home of a number of sky observatories(天文台). One of them, the Mamalluca, is quite different from the typical observatories used by scientists. This observatory was built for tourists who like to look at the stars. During the year, Vicunas hotels accommodate thousands of tourists who come from all over the world to see the night sky as they have only seen it in books. The cloudless sky is clearly a moneymaker for the town, which plans to set up even more observatories. It was recently decided that building observatories would go on for another few years.

At one point, however, the town faced a serious problem. As the town grew, more streetlights were added, making it more and more difficult to see the stars at night. The town saved the night sky by building a new system of lights that lit up the streets without influencing the view of the sky.