The other green planet
by James Somers, September 28, 2010
Here’s a simple argument for the existence of extraterrestrial life: there are hundreds of billions of galaxies that each have hundreds of billions of stars. Our sun may be special in many ways, but it can’t be that special.
I used to be deeply unsure about the prospects for life elsewhere in our universe. I used to think that stories of aliens and exoplanets were thrilling but basically pathetic fantasies. Then, not too long ago, I read about the Hubble Deep Field, realized that the specks of light in that image are galaxies, went on to read that there are in the neighborhood of 10^22 stars in the observable universe, and immediately concluded that it is tremendously, profoundly stupid to think that we’re alone.
That seems to be the minority opinion. Ask someone at random whether they think there are aliens. If they don’t say “no,” they will at least be agnostic, and more likely dubious. Virtually nobody will confidently argue for their existence, and most of those that do will do so for the wrong reasons.
The biggest problem seems to be with the numbers. Ten billion sounds about as enormous, to the lay man, as ten sextillion, even though it’s a full thirteen orders of magnitude smaller. So the argument above loses a lot of its force just because people aren’t as impressed by “10^22″ as they ought to be.
It doesn’t help that we’re wired with a first-person view of the world, a view which has the effect of making each of us feel like the center of the universe. That feeling is probably single-handedly responsible for thousands of years of scientific false starts: the idea that the Sun revolves around the Earth, that our solar system is at the center of the galaxy, that humans were created beside and above the other animals, etc. It took an incredible amount of discipline to abandon this inborn self-centeredness and embrace a simple truth: that in the grand scheme of things, we aren’t all that special. 
The question I have, then, is what it would take for the mass of mankind to begin believing, with near certainty, that there is extraterrestrial life. And what would be the effect of such a widespread belief?
One scenario that’s been beaten to death is direct contact with an alien race. This is tremendously interesting, but for my purposes it goes too far. So how about this: suppose that in the year 2012, instead of the world ending, our scientists discovered a green exoplanet, i.e., a planet outside our solar system covered in chlorophyll. What would happen?
While some people would no doubt hail it as the greatest discovery in the history of mankind, and triumphantly proclaim the abundance of extraterrestrial life, my guess is that there would be a lot of resistance. People would demand more evidence and, just as they have in the global warming debate, cast doubt on the mere existence of a scientific consensus. For a long time they’d attack the credibility of the data, the instruments used to collect it, the scientists involved in analyzing it, and the press engaged in its popularization.
Let us suppose, though, that after enough debating and demanding and re-appraising, the existence of plant life on this exoplanet became about as credible and common a belief as the theory of evolution, that is, it became taken for granted by the educated mainstream. What then?
I think something pretty cool would happen. I think that being a kid growing up in “the era of the other green planet” would be a bit like growing up in Europe in the early 14th century, just when Marco Polo’s tales of a strange and wonderful far-off land were gaining traction among the public.  Your imagination would be forced to radically and irrevocably expand: what you once took to be the only way of being would be made small in its proper context, and you’d see our flora and our fauna and all our human apparatus—the courts and garbage men and roads and police and clothing and markets and so on—as so many accidents of history, some more evitable than others, each further fixing Earth’s minor place in a vast uncountable sea of possible worlds.
Which is to say that credible evidence of an alien planet, one too far away to examine directly, would force us all, first, to think of Earth as a world rather than the world, and second, to imagine what all the other worlds out there might be like, starting with the one scientists know for sure exists.
I think that qualifies as a paradigm shift. It would have all sorts of consequences:
The academic’s trick of adopting “a Martian’s eye view” might go mainstream. What better way to kick off a discussion of money, say, than to ask students to “imagine there was an intelligent species on the other green planet. What would they say about you trading a piece of paper for a chocolate bar? Which parts of our economic system would seem strange to them, and which might make sense?”
Students who study abroad have this somewhat irritating tendency, when they get back, to sing the praises of all things “there” at the expense of all things “here” (“The trains are really so much better in Japan,” or, “Americans can’t make a decent cup of coffee,” etc.). But that kind of doubt about one’s home—that critical eye—is no doubt useful. And certainly something of that sort would happen if more of us took extraterrestrial life seriously: we might be a little more ambivalent about ourselves, and a little more humble.
Science fiction writers have always been painting pictures of other worlds full of strange landscapes and life-forms and customs. But that kind of creative imaginative activity could belong to everybody, once it became natural—rather than nerdy—to think about exoplanets.
It’s natural to the point of being a cliché to occasionally look up on a clear night and marvel, and to ask yourself whether someone else, somewhere around the globe, is marveling with you. Or to find yourself in the grip of sadness and be comforted by the thought that perhaps millions of other people are crying at the very same time. How much richer would those moments be if you considered also the experience of every other sentient sensitive being in the ‘verse?
If nothing else I get a thrill out of imagining our dark cosmos teeming with colorful life. But I insist that this isn’t wishful thinking. In fact, I think it’s the conservative position, and that to think we’re alone is not just sad but crazy.
 See Carl Sagan’s “Pale Blue Dot” for a wonderful articulation of this theme.
 The Marco Polo analogy is due to my mother, who introduced it in a brief but entertaining conversation about aliens on the porch of our cottage overlooking Lac Echo.