"Do you want to have a talk with aliens？What do they look like？Where do they live？…" People are always wondering whether there is intelligent life on other planets. For many 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 both believe intelligent life exists(存在)somewhere in the universe. They think we will sooncontactthese beings as well.
Why do Shostak and Barnett think intelligent life exists on other planets？The first reason is time. According to the careful research, scientists believe the universe is about 12 billion years old. "This is long enough for other planets to have intelligent life," say the two astronomers—Shostak and Barnett. The second important reason is size—the universe is huge. "Tools like the Hubble Telescope(哈勃望远镜)have shown us 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 as time goes by, powerful telescopes allow scientists to discover some smaller planets—the size of Mars or Earth in other solar systems. These planets might have intelligent life.
Have beings from space already visited our Earth？"Probably not, " says Shostak. "It's a long way away. However, intelligent beings may contact us in other ways, 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. "
