PASSAGE 4
Is there intelligent life on other planets? For years, scientists said “no” or “we don’t know”. But today, this is changing. Seth Shostak and Alexandra Barnett are astronomers. They believe intelligent life exists somewhere in the universe. They also think we will soon contact these beings.
Why do Shostak and Barnett think intelligent life exists on other planets? The first reason is time. Scientists believe the universe is about 12 billion years old. This is too long, say Shostak and Barnett, for only one planet in the entire universe to have intelligent life. The second - the universe is huge. Tools like the Hubble Telescope “have shown that have shown that there are at least 100 billion galaxies,” says Shostak. And our galaxy, the Milky Way, has at least 100 billion stars. Some planets circling these stars might be similar to Earth.
Until recently, it was difficult to search for signs of intelligent life in the universe. But now, powerful telescopes enable scientists to identify smaller planets - the size of Mars or Earth - in other solar systems. These planets might have intelligent life.
Have beings from space already visited Earth? Probably not, says Shostak. The distance between planets is too great. Despite this, intelligent beings might eventually contact US using other methods, such as radio signals. In fact, they may be trying to communicate with us now, but we don’t have the right tools to receive their messages. But this is changing, says Shostak. By 2025, we could make contact with other life forms in universe.
(Reading Explorer 1, Cengage Learning National Geographic)
1. The main purpose of this reading passage is.
A. to show how telescopes work
B. to explain the ideas of two scientists
C. to explain how life started on Earth
D. to describe what life on other planets might look like
2. What would be a good title for the second paragraph?
A. The Age and Size of the Universe B. Earth: The Only Planet with Intelligent Life
C. Our Galaxy: The Milky Way D. Why Intelligent Life Might Exist
3. Why was it harder to look for signs of intelligent life in in the universe in the past?
A. Planets used to be farther apart. B. We did not have the right tools.
C. We could only see smaller planets from Earth. D. These lives might not exist then.
4. According to Shostak, might prevent beings from space visiting our Earth.
A. the great distance B. the radio signals C. the unread messages D. our planet size
5. In the last paragraph, what does “life forms” refer to?
A. planets B. radio signals C. intelligent beings D. messages
