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There is good news and bad news in the quest for extrasolar planets as possible sites for the rise of intelligent life. The good news is that astronomers are beginning to find convincing evidence for planets in orbit around stars like the sun. The bad news is that none of the planets discovered so far is anything like the earth. Instead, they are all giants, at least 100 times more massive than the earth, and unlikely to be suitable for life as we know it.

The first good evidence for a system of planets orbiting a solar-type star was announced April 15, 1999, by a team of astronomers from four research institutions.Butler, R. P., Marcy, G. W., Fischer, D. A., Brown, T. M., Contos, A. R., Korzennik, S. G., Nisenson, P., and Noyes, R. W., 1999, ApJ, 526, 916 The three planets in this system are also giants. But, if they are like the giant planets in our own solar system, they will have rocky moons, and one of those moons just might prove to be inhabited (but I would not bet on it). More importantly, now that we have more than just one example of a planetary system, it is easier to imagine that somewhere there may be other systems with earth-like planets orbiting in a habitable zone.

Contributed by: Dr. David Latham

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David Latham

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