Level 1 Reading 4A

Ch.7

Reading 4A LIFE BEYOND EARTH? Is there intelligent life on other planets besides Earth? For years, scientists weren't sure. Today, this is changing. Seth Shostak and Alexandra Barnett are astronomers. They believe intelligent life exists elsewhere in the universe. They also think we will soon contact these beings. Why do these astronomers think intelligent life exists on other planets? The first reason is time. Scientists believe the universe is about 12 billion years old. According to Shostak and Barnett, this is too long a period for only one planet in the whole universe to develop intelligent life. The second reason is size—the universe is huge. Tools such as the Hubble Telescope 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 that circle these stars might be similar to Earth.

Looking for Intelligent Life Until recently, it was difficult to search for signs of intelligent life in the universe. But now, powerful telescopes allow scientists to identify many more small planets— the size of Mars or Earth—in other solar systems. If these planets are similar to Earth and are close enough to a star, they might have intelligent life. Making Contact Have beings from outer 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 or flashes of light. In fact, they could be trying to communicate with us now, but we may not have the right tools to receive their messages. This is changing, however, says Shostak. He predicts that we will make contact with other life forms in our universe within the next 20 years.

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