1 . Have you ever got the thought or feeling that you’re being watched? Well, guess what? You might be right.
According to a study published in Nature on June 23, 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 previous method that looked for life on other planets. But instead, they changed the method so it could try to determine what places could see us.
The team looked at 331,312 stars within 326 light-years of Earth, with each light-year equaling 9.4 trillion kilometers. 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 somebody is waving,” said Lisa Kaltenegger, director of the Carl Sagan Institute (研究所) 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 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 traveled 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 anymore.
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. Which word can best describe Lisa Kalteneggers’ attitude towards the sky that he looked up at?| A．Objective | B．Indifferent | C．Critical | D．Positive. |
| A．The oxygen on Earth. | B．Human-made radio waves. |
| C．Advanced life in other planets. | D．A planet circling around one of those 1,715 stars. |
| A．Aliens don’t exist. | B．They cannot understand each other. |
| C．It takes a long time for messages to travel. | D．Human-made radio waves cannot travel far. |
| A．To present new findings published in a study. |
| B．To raise readers’ interest in aliens and the universe. |
| C．To discuss if there is advanced life on other stars. |
| D．To explain how messages travel between different star systems. |
2 . Scientists working in NASA say they have made a significant discovery that a huge star seems to have disappeared from the universe. The star is part of the Kinman Dwarf galaxy, pictures of which were taken in the past by a camera attached to NASA’s Hubble Space Telescope. But since the galaxy is so far away, researchers have not been able to clearly observe its stars. Astronomers had, however, identified important “signatures”, or signs, that the massive star existed. Now they are searching for answers to why it is no longer possible to see them.
A team of scientists from the European Southern Observatory reported it had been observing the star with its Very Large Telescope, VLT, for at least 10 years. The team said its observations repeatedly showed evidence that the Kinman Dwarf galaxy contained the massive star, which was estimated to be about 2.5 million times brighter than our sun. Researchers said the evidence suggested that the star was “in a late stage of its evolution”. They added that the star was a kind considered to be “unstable”. This means it could go through major changes in brightness or lose some of its mass.
Andrew Allan, the project’s leader, said the researchers wanted to learn more about how massive stars end their lives. The massive object observed in the Kinman Dwarf galaxy seemed like the perfect target. But when astronomers turned the VLT toward the distant galaxy in 2019, they could no longer find any signs of the massive star. “Instead, we were surprised that the star had disappeared,” Allan said in a statement.
The astronomers are now exploring two possibilities. The first is that the star might have become less bright and could be partly blocked by dust. The other possibility is that it collapsed into a black hole without producing a super powerful explosion.
The astronomers plan to keep observing the galaxy for signs of the missing star. They will likely need to wait a few years before confirming what happened to this particular star.
1. What does the underlined word “them” in Paragraph 1 refer to?| A．The stars. | B．The galaxies. | C．The signatures. | D．The astronomers. |
| A．It was once clearly observed. | B．It experienced a temporary change. |
| C．It could only be traced with the VLT. | D．It evidently existed in the distant galaxy. |
| A．It exploded. | B．It lost some of its mass. |
| C．It evolved into a black hole. | D．It was damaged by dust and became less bright. |
3 . Do you think alien beings exist somewhere in the universe? It seems like Mars, our closest neighbor, has inspired the most science fiction as the place where aliens are most likely to come from. Recent Mars probes (探测) have shown us that there is no life on that planet—at least not now. But that does not mean that life does not exist elsewhere—after all, the universe is really big. A lot of scientific research is going on in the search for “extraterrestrial life”.
Think about it—why should the seven billion people on this little planet be the only living beings in the universe? It would, in fact, seem logical that this is not the case. So scientific research in this matter is based around the idea of finding other planets that have environments that can support life —environments similar to the Earth. The search is on for the evidence of the existence, or earlier existence of life: from very wise beings to simple organisms (有机物).
So far, there have been a number of theories as to which planetary bodies may have an atmosphere that can support such life and therefore deserve closer attention. As for places within our own Milky Way Galaxy, it has been assumed over the decades that Mars and Venus, as well as some of the moons of Jupiter and Saturn, may have been hosts for life. Now, as technologies have improved and we can obtain measurements of the composition of the atmosphere on extra-solar planets, the chances of finding “alien” life forms are increasing.
There has been a theory that some of the planets in the habitable zone of the red dwarf star Gliese 581 may be able to support life. In 2007, scientists discovered exoplanet Gliese 581c—and felt that its atmosphere was most suitable for supporting life. But further research revealed that it would not. Now, attention has been turned to Gliese 581d, at the outer edge of the star’s habitable zone. The main standards for deciding whether a planetary body can be life-supporting are atmospheric conditions which allow the existence of water. Gliese 581 is about 20. 4 light years away from the Earth, so even if life does exist there, the distance would mean that communication would be unlikely.
Having said this—who says alien life forms (if they exist) need water?
1. What does the underlined part in Paragraph 1 mean?| A．Life existing outside of the Earth. |
| B．The evidence of the existence of life. |
| C．Other faraway planets in the universe. |
| D．Creatures known from science fictions. |
| A．Modern scientific theories. | B．Atmospheric conditions. |
| C．Environments similar to the Earth. | D．Advanced technologies. |
| A．the atmosphere of Gliese 581c was most suitable for life |
| B．it is not certain whether alien life forms need water or not |
| C．the 7 billion people on the Earth are the only beings in the universe |
| D．the distance of 20. 4 light years makes it impossible to find life on Gliese 581d |
| A．Do Aliens Exist? | B．Is Mars Suitable for Life? |
| C．Are Alien Life Forms Various? | D．Can We Communicate with Aliens? |
