Are We Alone?
From ancient times,/people have wondered/if there are other planets like Earth.// That is still an open question today.// Richard Dawkins tells us/that we are getting closer to an answer.//
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　　Is there life on other planets?// Nobody knows for sure,/but I’d say yes.// One day/we may have clear evidence/of life on other planets,/but for now,/the best we can do/is to reduce the uncertainty.//
　　The first thing we might ask/is how many planets there are.// People used to believe/that the ones orbiting our sun/were the only ones.// But now we know/that in our galaxy/most stars have planets.// So,/we can probably conclude/that most of the stars in the universe/have planets.//
　　The number of stars in our galaxy/is about 100 billion,/and the number of galaxies in the universe/is about the same.// That means/10,000 billion billion stars/in total.//
　　According to astronomers,/only about 10 percent of stars/are like the sun.// Stars that are very different from the sun/are unlikely to support life on their planets/for various reasons:/for example,/stars that are much bigger than the sun/will not last long enough before exploding.// But even if we are talking/only about the planets orbiting sun-like stars,/we are dealing in billions of billions.//