1 . We all live on Earth and enjoy our life every day. Do you know all the interesting facts about the Earth?

The Earth is not round.

Do you think the Earth is round? Will the Earth is not completely round.

The Earth is really old.

Grandmas and grandpas are old, but the Earth is much older. Scientists think that the earth is about 4.5 to 5 billion (十亿) years old.

Much of the Earth is water.

About 70% of Earth is water, and only about 30% of Earth is land.

Earthquakes happen all the time.

Earthquakes (地震) take place all the time. But most of the time, they are very small and human beings cannot even feel them.

________.

There are many mountains on Earth. Mount Everest is the most famous one because its peak is five and one-half miles above sea level. It is the highest. There are more interesting facts about the Earth. Can you tell us some?

2 . China’s Chang’e 5 mission is the most recent successful lunar sample return mission. On Dec 17, the Chang’e 5 lunar probe（探测器）returned home along with 1.7 kg of lunar rocks and soil.

The main goal of Chang’e 5 was to bring things back. And China’s new samples stand for a fresh start for its lunar research and space exploration.

The samples were collected at Mons Rumker, also known as the Ocean of Storms. The site has never been sampled（取样）before. Samples that were taken by the US previously（以前）are all more than three billion years old, while the Chang’e 5 samples are less than two billion years old. Scientists are now able to study late-stage（后期）volcanic（火山的）activity on the moon. This activity shaped the younger parts of the rocky moon we see today, according to Long Xiao, a scientist at the China University of Geosciences.

The moon’s volcanic history is not the only mystery that Chang’e 5 is going to solve. The mission could also help scientists learn more about the history of the whole solar system（太阳系）. Scientists will check the amount of radioisotopes（同位素）in the samples to accurately（精确地）date（确定年代）them-the radioisotopes decay（衰减）over time.

Dating lunar samples will give us more accurate ages not only for the moon, but also for other planets in the solar system. These planets are often dated by comparing them to similarly aged areas of the moon.

7 . There must be something interesting. People around the world felt excited on the night of April 10, 2019. For the first time in history, people saw a photo of a black hole. The photo became popular immediately(立刻). But do you know it has something to do with a computer scientist Katie Bouman? Without her, there wouldn’t be this photo. Black holes are very far from us, so it is very difficult to take photos of them. It’s like taking a photo of an orange that is on the moon. Many scientists have tried it. However, none of them succeeded. These failures didn’t stop Bouman from trying. Several years ago, she started working on a special computer program. During the past years, she has improved the program many times. Finally, it turned telescope data(望远镜数据) into a photo of a black hole.

Bouman has received lots of praise(赞扬) because of her work. However, the young woman is modest. She said success mainly depended on her team. “None of us could do it alone,” she said. Would you like to make history as Bouman did? Set a goal for yourself and work hard at it. Maybe you will make it come true in the future.

8 . Scientists think that there has been life on the earth for millions     1     years. However, we     2     found life on any other planets yet. The earth is a planet and it goes around the sun. And there are seven other planets that also go around the sun. The sun and     3     planets are called the solar system. The solar system is a small part of the universe.

Scientists has launched many spaceships to explore other planets in the solar system.Some spaceships have gone beyond the solar system. However, no one has discovered any life in space     4    .

Why has no one from other planets sent us a message? Have they tried     5     send information to us? With so many stars in space, are we alone, or is there life on other planets in space?

10 . Scientists always want to know more about the universe（宇宙）.

Years ago they knew many things about the moon. They knew how big it was and how far away it was from the earth. But they wanted to know more about it. They thought the best way was to send men to the moon.

The moon is about 384,000 kilometers away from the earth. A plane cannot fly to the moon because the air reaches only 240 kilometers away from the earth. But something can fly even when there is no air. That is a rocket.

How does a rocket fly? There is gas in the rocket. When the gas is made very hot inside the rocket, it will rush out of the end of the rocket, so it can make the rocket fly up into the sky.

Rockets can fly far out into space. They send spacecrafts to the moon. Spacecrafts with men in them have been to the moon. Several spacecrafts without men in them have flown to another planet much farther away from the moon. One day men may be able to go to any places in space.