7.
阅读理解
Is there intelligent (有智力的) 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 (天文学家). They believe
intelligent life exists (存在) somewhere in the universe.
They also think we will soon contact these beings (人;生物).
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 long enough for other planets to have
intelligent life," say Shostak and Barnett. The second reason is size—the
universe is huge. "Tools like the Hubble Telescope (哈勃望远镜) 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 going around these stars
might be similar to Earth."
In the past, it was hard to look for signs of intelligent life in the
universe. But now, powerful telescopes (高倍望远镜) allow scientists to discover 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. "It's a long way away. However, intelligent beings may
contact us in other way, such as radio signals (信号). In fact, they may be trying to communicate with us
now, but we don't have the right tools to receive their messages. However, this
is changing. By 2025, we could make contact with other life forms in our
universe and we might help each other."