Tuesday, April 24, 2007

Extraterrestrial Life?

These results are exciting, but I can tell you to read with a grain of salt. The claim that this "... may be the first habitable planet orbiting a nearby star" is perfectly true so long as you keep your mind focused on that word "may". One problem with transferring scientific discoveries to the general public is the fact that in sentences like the one quoted that "may" too often gets translated to "probably is". "Probably is" is wrong, "may" is right. That's why they said "may". Scientists do try and use just the right words to say things, that is kind of why jargon becomes so common. But I digress.

This news is exciting because it does indicate that there exist planets close in size to that of the earth near other stars. As the article says, getting the size of a planet, especially a relatively small one, exactly right at the huge distances from here to other stars is very difficult. Now remember what I said about being careful with words. I said "exactly right". What I mean is that it could be the size of Mars (smaller than the earth) or the somewhat bigger than the earth (I believe that they estimate 1.5 times the size of the earth), but it's not the size of Jupiter. So it is a rocky planet that could have once had an atmosphere and might still have one. The star it is orbiting is a red dwarf, so it is much older and cooler than the Sun, but if there was once life on the planet, there might still be life there now.

On the other hand, this planet is not just like the earth, so if the conditions for life to form require something just like the earth then it might still be barren. Or if it once had life, but life could not hang on, it would be barren. However, that said, this confirms that this solar system is not unique and that there are planets smaller than Jupiter orbiting other stars. Also, we can safely assume that if there were only a very few such planets, we would not have found them. This is not the only such small, earthlike planet out there. Therefore it is also likely that there are other planets, more like the earth, and more likely to have life, out there.

This planet is, what I would call, a likely candidate for extraterrestrial life. It could well be there, but we haven't found confirmation yer.

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