Post by patrickm on Apr 19, 2011 15:57:28 GMT -6
The Search for Life in the Universe
Read the rest of this wonderfully thoughtful essay at the Hayden Planetarium website and consider how much we have discovered since this was written just fifteen years ago!
originally in Natural History Magazine, September 1996
Published under the title "Is Anyone Out There Like Us?"
The recent discovery of about half a dozen planets around stars other than the Sun has triggered tremendous public interest. Attention was driven not so much by the discovery of extra-solar planets, but by the prospect of them hosting intelligent life. In any case, the media frenzy that followed was somewhat out of proportion with the events. Why? Because planets cannot be all that rare in the universe if the Sun happens to have a bunch of them. Also, the newly discovered planets are all oversized gaseous giants that resemble Jupiter, which means no convenient surface exists upon which life as we know it could live. And even if they were teeming with buoyant aliens, the odds against these life forms being intelligent may be astronomical.
Ordinarily, there is no riskier step that a scientist (or anyone) can take than to make sweeping generalizations from just one example. At the moment, life on Earth is the only known life in the universe, but there are compelling arguments to suggest we are not alone. Indeed, most astrophysicists accept the probability of life elsewhere. The reasoning is easy: if our solar system is not unusual, then there are so many planets in the universe that, for example, they out-number the sum of all sounds and words ever uttered by every human who has ever lived. To declare that Earth must be the only planet in the universe with life would be inexcusably bigheaded of us.
Read the rest of this wonderfully thoughtful essay at the Hayden Planetarium website and consider how much we have discovered since this was written just fifteen years ago!