Why is it called Mars（火星）? Well, Mars is the name of the Roman god of war（罗马战神）. People see the planet（星球）as a symbol of war for thousands of years. It is also known as the Red Planet because of its color. It is red because it’s rich in iron（铁）. Chinese people called it the “fire star” for the same reason.

Scientists was interested in the planet. They first saw Mars in the sky more than 4, 000 years ago. Then, people from all over the world studied the planet. About 200 years ago, scientists started to study pieces of Mars. They broke away and drifted（漂流）through space for millions of years before they got to Earth.

Scientists have learned some things about Mars. For example, Mars is home to a 21-kilometer-tall mountain—the tallest in our solar system（太阳系）. However, Qomolangma, Earth’s highest mountain, is just 9 kilometers tall. Like Earth, Mars has moons. It has two moons named Phobos and Deimos. The Red Planet also has the largest dust storms（沙尘暴）in the solar system. And they can last for months.

Earth is 10 times heavier than Mars. So The Red Planet’s gravity（重力）is only 37 percent as strong as Earth’s, meaning you can jump nearly two times higher on Mars. For the same reason, you are two times heavier on Earth than on Mars.

【推荐2】All the planets in the solar system go around the sun. There are eight planets in the solar system. Years ago, there were nine planets. Ever since Pluto (冥王星) was demoted (使降级), we’ve had just eight planets.

Some scientists have studied the farthest reaches（研究）of our solar system. They believe there might be another planet out there. They call it Planet Nine. What would Planet Nine be like? Scientists believe it could be about three times larger and ten times heavier than the earth.

If Planet Nine is out there, why haven’t we found it yet? Scientists are still reaching for it because it’s so far away. They believe it could take Planet Nine as long as 20,000 years to go around the Sun. Scientists also think Planet Nine could be as much as 10,000 times darker than Pluto.

It is very difficult to search for such a dark planet in the whole solar system. Could our solar system have a ninth planet? We hope to know the answer in the near future.

【推荐1】As we all know, dangers（危险） are everywhere in our daily life. So you should know some ways to keep safe.

When you go outside, you should always notice the environment（环境） around you.

You had better not walk alone（独自）. If you don’t have a mobile phone with you, you need to make sure where the public phones are.

When you are in a bus with many people, your bag should be carried towards the front of your body instead of putting it on your back. It is easy for a thief（小偷） to steal the things from the bag on your back.

If someone you don't know goes after you, cross the street and go to the other way. Let the person understand that you know he or she is after you. Next, don’t go home at once.

If you have to take a bus to a place, try to get to the stop a few minutes earlier before the bus leaves. On the bus, don't sit alone or sleep.

【推荐3】Have you ever seen lions dancing in the streets? The lions dance to the beat of a drum. Of course, they are not real lions. They are dancers in lion costumes (服饰). Lion dancing first started in China centuries ago. It is meant to bring good luck in the coming year. Usually, a lion is made up of two dancers. One dancer controls the head. The other controls the tail.

“I think of it as a sport,” says Anthony Huang, aged 16. He is a member of the New York Chinese Freemasons Athletic Club. Anthony performs (表演) as the lion’s head. It can weigh 20 pounds. Lion dancing is important to Anthony. “This tradition really lifts me up,” he says.

In the past, lion dancing was performed mostly by men. But it is different today. LionDanceMe is a lion dancing group in San Francisco, California. There are boys and girls on its team. They dance together. “Anyone can take up lion dancing. You have to believe that you can do it,” says Ananda Tang-Lee, a 17-year-old girl.

Lion dancing will continue to evolve. But a team’s sense of community will never change. “We call it a family,” Ananda says. “It’s really great, because we always have each other’s backs.”