After spending years searching for a planet with life, scientists may have found one. In September 2010, a team of US scientists discovered an Earth-sized planet called Gliese 581g. It has a surface temperature neither too hot nor too cold for liquid（液态）water. Scientists think there is a chance that the planet could have life.The planet Gliese 581g goes around a star called Gliese 581, which is about 20 light-years from Earth. That is about 194 trillion（万亿）kilometres －500 million times farther away from us than the moon.
A spacecraft traveling at a one-tenth of the speed of light would reach Gliese 581g within about 220 years. A human can’t live that long, but robotic explorers could make the job easier. However, our fastest spacecraft don’t come anywhere near that one-tenth light-speed mark.
At present, scientists don’t know what the surface might be like on Gliese 581g. What they know is that the planet is at the sight distance from its star to have liquid water. It’s also at the right distance to have an atmosphere that could protect the water if it is on the surface.
Although spacecraft won’t be getting there anytime soon, one way to look for life on Gliese 581g is to turn our radio telescopes（望远镜）towards the planet and search for radiation（放射）. By studying the radiation, scientists would find out about the chemicals（化学物质）around the planet and discover it Gliese 581g has an atmosphere. If it has one, studying the atmosphere would give us a good idea if the planet has life or not. But it’ll probably be many years before we can do this properly.
People have been arguing about whether there is alien life on Gliese 581g. Any discussion about alien life is just guessing at this point, according to its discoverers.
1. What did scientists find in September 2010?
| A．A planet with water. | B．A planet similar to the earth. |
| C．A planet without life. | D．A planet near the earth. |
| A．is at the right distance from its star | B．moves around the earth |
| C．is as far away from us as the moon | D．can be reached in about 220 years |
| A．the possibility of living on Gliese 581g |
| B．the kinds of chemicals around Gliese 581g |
| C．the way of looking for life on Gliese 581g |
| D．the aim of studying the radiation on Gliese 581g |
| A．Gliese 581g, a Likely Living Planet | B．Gliese 581, a Likely Living Planet |
| C．Gliese 581g and Its Star | D．Gliese 581g and Radiation |
相似题推荐
The Moon is a natural satellite that moves around the Earth.
The Moon’s surface is covered with craters (环形山), which are big round pits.
Do you know that humans have actually visited the Moon? In 1969, the Apollo 11 mission landed astronauts Neil Armstrong and Buzz Aldrin on the Moon’s surface.
| A．It is our closest neighbour in space. |
| B．The Moon plays an important role in our lives. |
| C．Do you know how many satellites the Earth has? |
| D．They were the first humans to set foot on the Moon. |
| E．Have you ever noticed that the Moon changes its shape? |
| F．These craters were formed by asteroids (小行星) and meteoroids (流星体) crashing into the Moon’s surface. |
【推荐2】Venus (金星) is close to Earth.
Scientists have been learning about Venus for a long time. First, they looked at Venus through telescopes (望远镜). But Venus is covered with thick clouds.
For a long time, scientists thought that Venus had water and plants. They thought Venus might have animals, too.
| A．Then scientists found a way to learn more about Venus. |
| B．It is the second planet from the Sun. |
| C．The scientists learned a lot from the probes. |
| D．But they didn’t know for sure. |
| E．Scientists could not see Venus well through the clouds. |
【推荐3】Do you ever get the feeling that you’re being watched? Well, you might be right.
According to a study published in Nature on June 23 th, astronomers have found that 1,715 stars have had a direct view of Earth since humans have been here.
In order to do this, scientists used a method that looked for life on other planets. But instead, they changed the method so it could try to decide what places could see us.
The team looked at 331,312 stars within 326 light-years of Earth. Out of all those stars, only 1,715 of them could see Earth within the last 5,000 years, with an extra 319 stars that will be able to see us in the next 5,000 years.
“When I look up at the sky, it looks a little bit friendlier because it’s like, maybe someone is waving,” said Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University, US, and the study’s lead writer.
If a planet circling around one of those 1,715 stars is home to advanced (高级的) life, they could easily see that there is life here because of the oxygen on Earth. If that didn’t give it away, then the radio waves we have sent out into space would also be an indicator (标志). In fact, human-made radio waves have already travelled through 75 of the closest stars on Kaltenegger’s list.
Why haven’t we heard from anyone yet, then? It takes a long time for messages to travel between star systems. By the time a message could be received, that advanced civilization (文明) would probably not exist any more.
Alan Boss, a scientist at the Carnegie Institution for Science in the US who wasn’t part of the study, wrote in an email that this long time would limit the chances for different life to exchange “emails and TikTok videos. ”
“So we should not expect aliens to show up anytime soon,” Boss said.
1. How many stars will be able to see us in the next 5,000 years?| A．319. | B．1,715. | C．1,396. | D．2,034. |
| A．A planet circling around one of those 1. 715 stars. | B．Advanced life. |
| C．Oxygen on Earth. | D．Human-made radio waves. |
| A．Human-made radio waves cannot travel far. | B．Aliens don’t exist. |
| C．They can’t understand each other. | D．It takes a long time for messages to travel. |
| A．To show new findings published in a study. |
| B．To discuss if there is advanced life on other stars. |
| C．To raise readers’ interest in aliens. |
| D．To explain how messages travel between different star systems. |
