Tuesday, June 14, 2005

Found: Earth's Distant Cousin (About 15 Light-Years Away) - NYT

The detection of extrasolar planets is a great wonder of our times. It's a way to test the likelihood of other forms of life in the universe.



Found: Earth's Distant Cousin (About 15 Light-Years Away)

Published: June 14, 2005

In a discovery that they described as a milestone in the quest to find out if humans are alone in the universe, astronomers announced yesterday that they had found the smallest planet yet outside the solar system.

With a mass only seven times that of the Earth, the new planet is probably a ball of rock, its discoverers said. Orbiting closely to a dim red star in Aquarius known as Gliese 876, it is the third and innermost member of a shrunken version of our own solar system.

"This is by far the most Earth-like planet ever found," said Dr. Geoffrey Marcy of the University of California, Berkeley, a member of the team that made the discovery using one of the giant 10-meter diameter Keck telescopes in Hawaii.

To understand the importance of the discovery of Earth-like planets, it's good to mention what the "Drake Equation" is about:

1> There are more or less 250 billion galaxies in the universe.
2> In each galaxy, there are more or less 200 billion stars
3> More than 30% of these stars have planets
4> In each solar system, there are about 2 potential life-supporting planets
5> Among such planets, only one in a million actually supports life...

There would still be more than 30 billions of billions planets with some forms of life in the universe! (More than 100 millions in our galaxy alone)

The more Earth-like planets will be discovered, the more accurate will be the parameters in the Drake Equation!

Note than very few astronomers doubt that life is widespread in the universe these days...



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