An article appeared on Space.com a few days ago about a newly discovered planet, Gliese 581g. If you’re not familiar with new planets, this planet (called an extrasolar planet because it’s outside our solar system and revolves around another star) was reported on September 29 as the first “earth-sized” planet ever found that resides in the habitable zone, the area around a star where it’s not too cold and not too hot, where life could conceivably develop, all other things (liquid water, suitable atmosphere, etc.) present as well. Now, it seems, the existence of this planet is being called into question by a different group of astronomers. They reviewed the measurements that the original group made and said they had serious reservations that the planet existed.
A lot of measurements have to be taken to detect a planet revolving around a star a hundred light years or more away. Months of measurements, in fact. And a lot of computer time. The existence of the planet is based on inference, slight movements of the star itself, detectable only after months of observation. (Only one planet that I’ve heard about has ever been visualized directly, and even that one was little more than a tiny dot in the telescope image.) So, this planet, Gliese 581g, was “observed” more by computer than by eyesight, and the data that was fed into the computer is subject to interpretation. The fact that this planet may not exist has astronomers in an uproar.
All of this makes such a big deal because we, as inhabitants of the only planet we know of on which life developed, seem to have some ingrained necessity to find life somewhere else in our universe. Several billion stars exist in our galaxy, and the assumption is that some star, some where, must have a planet around it where life developed. The chances are too great for it not to. But of over 500 extrasolar planets we’ve found, only this one, Gliese 581g, has the potential to host life, and now it’s suspect.
I’ve never understood this addiction to finding another planet. So many people want to find life somewhere else, whether it’s on Mars, or the moons of Jupiter or Saturn, or around another planet in our galaxy. “I can’t believe we’re alone,” they cry. We’ve poured tons of money into the SETI project [Search for ExtraTerrestrial Intelligence] which, in over 30 years of listening for signals from outer space, has yet to record a definite find, and now the one good possibility for a habitable planet has been questioned.
Let’s face it: we may be alone in this part of the galaxy. That concept bothers so many people, but it doesn’t bother me. What difference does it make? The human animal has been alone for as long as it’s been on this planet (if we’ve been visited from outer space, we’ve never found any good, hard, solid evidence for it). We’ve developed as a species over millions of years without any outside help, we’ve gone about the business of improving ourselves and our planet alone, and we’ve produced a society that is intelligent enough to cultivate the concept of “other worldly life” all by ourselves. No outside help needed. Doesn’t that say something about us? Do we need extraterrestrial life to validate that accomplishment?