

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 sill 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 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 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 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 . 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."

Now, provide a numbered list of answers to these questions:

1. Are we able to communicate with other planets?
2. Why not?
3. Will we ever?
4. When?
5. Who thinks that?
6. Who is he?
7. Does he believe in alien intelligent life?
8. Do others believe that?
9. Who else?
10. Who is that?
11. What do they think?
12. What makes them so sure?
13. What about time?
14. Why does that matter?
15. What's another reason?
16. How big?
17. Why does that matter?
18. Why is that important?
19. How would we know if there was life?
20. Has earth already been visited by aliens?
21. Why not?
1. No
2. we don't have the right tools to receive their messages
3. Yes
4. By 2025
5. Seth Shostak
6. astronomer
7. Yes
8. Yes
9. Alexandra Barnett
10. astronomer
11. intelligent life exists somewhere in the universe
12. The first reason is time
13. the universe is about 12 billion years old
14. This is long enough for other planets to have intelligent life
15. size--the universe is huge
16. at least 100 billion galaxies
17. our galaxy, the Milky Way, has at least 100 billion stars
18. Some planets going around these stars might be similar to Earth
19. powerful telescopes allow scientists to discover smaller planets
20. "Probably not,"
21. It's a long way away