There are professions in which wishing a happy new year falls far short, and one of them is astronomer. For these explorers of the cosmos, the least one can wish for someone is a happy 2070. That is the date on which, according to the co-discoverer of exoplanets Didier Queloz, we will confirm whether life is a universal phenomenon, a property of chemistry more elemental that arises where physical conditions allow it. And, as far as we know, they must allow it on billions of worlds scattered throughout our galaxy, the Milky Way. Read in Materia an interesting interview with Queloz, the last Nobel laureate in Physics together with his mentor Michel Mayor, and director of the European Space Telescope Cheopswhich has just been launched into orbit to further investigate some of the 4,000 extrasolar planets that have already been discovered.
Scientists’ perception of the likelihood of life on other planets has changed in this century, largely thanks to Mayor and Queloz’s seminal discovery. There are 200 billion stars in our galaxy, and today we can estimate that most of them have orbiting planets. A substantial fraction of them must, by chance, be in the “habitable zone” of their solar system, neither so close to their star that the water has evaporated, nor so far away that it has frozen.
According to the best available organic chemistry, it doesn’t take much more to generate the basic molecules of life, the ones that make up metabolism, generate structure, and encode information. That we still don’t know how the first living cell on Earth was born doesn’t necessarily mean that the process is highly unlikely, but perhaps that our science is very clumsy. The mere fact that the appearance of the first bacteria on our planet was rapid (on the scales of geologists) suggests that the phenomenon is likely.
Of course, we can’t even hope to calculate its probability until we find more independent cases, if any at all. As long as that does not happen, we will continue to be free to consider ourselves the product of an immense cosmic coincidence, an idea that can be seen as the last mystical redoubt that resists the Copernican revolution: we may not be the center of the universe, but we are its only population. It also serves as a religion, doesn’t it?