The other day, the front page of CNN.com regaled for all of five hours in the announcement that an international team of scientists had found a planet that could potentially support life. The Time-Warner company can be forgiven for its short attention span: these days, exoplanets, as they're called, are more of a waiting game than a media draw.
The planet, whose catchy name is Gl 581 c, circles a red dwarf, and was discovered by a team led by Stphane Udry of the Geneva Observatory in Switzerland. The planet that caused the momentary stir is about 20.5 light years distant. For perspective, if you wanted to drive your car at the standard freeway speed, it would take you a little over 2 billion years to get there. I suggest carpooling.
Despite that, however, it circles one of the ten closest stars to our own, and provides our first look at an earth-like planet. The truly extraordinary thing about Gl 581 c is that it rests contently in that sweet spots scientists have named the "habitable zone", meaning that water could exist in a liquid form. That orbit is also sometimes called the "Goldilocks Zone" because it is neither too hot nor too cold for life to thrive.
So, if the discovery of Gl 581 c is so interesting, why did it get buried so fast? Part of it has to due with the fact that it was replaced by a juicier (i.e., more horrific) story, but there is another reason that has its roots in the nature of public opinion.
The excitement over life beyond earth has had a rough history. Spurred by new technology that has given us the ability to investigate planetary systems farther and farther beyond our own atmosphere - and in more detail - the question of whether or not we are alone in the universe has come tantalizingly close to our grasp on several occasions. The world shook in 1996 when it was first announced that life on Earth may have actually traveled here from Mars. Then it shivered when Europa, the second moon of Jupiter, proved to have a thin crust of ice covering its surface. Upon the discovery of Gliese 581 c, it fluttered as a few people finally released the breath they had been holding.
The reason for this is partially due to an impatience resulting from the hyperbolic expectations that are often spun from scientific announcements. There is an enormous gap between what might exist and what does exist, a gap that is not always acknowledged when important discoveries such as this occur. Science publicists, such as Carl Sagan, have worked for decades to combat the science fatigue created by such obstacles by upholding the importance that scientific discoveries have for the common person. But, philosophical ramifications aside, the discovery of an inhabited and habitable world outside our solar system may only matter if it is accompanied by similar revolutions on our home world.
If we do find another earthlike planet in our galaxy, and it is already inhabited by other organisms, as would be expected, we would never be able to live on it without a controlled environment around us. An abundance of microbes, not to mention previously undiscovered alien pathogens, would make entering a foreign ecosystem, unprotected, fatal. That limitation alone may make the practical implications of life on exoplanets less than stellar.
The person to blame for all this, as is so often the case, is Charles Darwin. Contact between the Spanish and the Native Americans living in the New World showed just how devastating the results could be when a population is exposed to a pathogen that had evolved elsewhere (in this case, smallpox) and that was on the same planet, separated by only a few thousand kilometers of ocean. Expand that model to a different planet trillions of kilometers away, and you have the potential for even more of a problem.
Hospitals, it seems, may be the ones to answer the question of whether or not life on planets such as Gliese 581 c is possible, and what it might look like. Medicine, and an emerging field called astrobiology, may be able to provide an answer to making contact with a world that has evolved for millions of years without human presence. Amazing creatures on earth, such as extremophiles, which can live in extremely cold and hot environments, have already demonstrated that a planet doesn't have to be exactly like earth to support life.
So, is there life on Gliese 581 c? That question may never be answered, but it is the closest we've come to finding a planet capable of supporting life outside our own solar system.