Once upon a time the question about life elsewhere in the universe was complicated by lack of basic information. From the time we knew that we lived in a galaxy and there were 400 billion stars in our galaxy, and that there were 200 billion other galaxies (so that’s, um, 80,000 billion billion stars as far as the telescope eye can see), it seemed likely that there would be many possibilities of life elsewhere.
But the unknown part of the equation was the number of stars which had planets. Then, recently, we began finding planets around other stars, but they were all uninhabitable gas giants, like our Jupiter and Saturn. Then smaller planets began to be seen as observations improved. Then smaller planets at right distance (the Goldilocks Zone – not too hot, not too cold) from stars. Now calculations show that on average every star has one or more planets. Billions of billions of stars – billions of billions of planets.
So now, almost overnight it seems, we know there are essentially infinite numbers of planets. What percentage could life have evolved on? Half? Quarter? Even if only 1% had the kinds of conditions that enabled life to emerge here we are still talking billions of occupied planets. And once you have life the Darwinian equations – variation + selection = adaptation; adaptation + isolation = evolution – mean that all kinds of interesting organisms are out there. Chances of high intelligence evolving? Very good, it has evolved many different times here.
It’s all just a matter of very high numbers and chance. Always was, but we didn’t know how high the numbers were before. Now we do there is no question but that there is a lot of life out there, and a lot of intelligent beings.
So, where are they? Well, a long way away. And unless physics is a lot odder than we think there aren’t going to be student exchanges or tourism between here and there and right over there. Certainly not before the dominant intelligent people here wreck this habitable planet (a long long way from the next one) by being unable to control their own CO2 emissions. I’m guessing there are other beings in the universe (Dolphin beings, or Octopus beings, or Crow beings, or Pig beings) who consider getting CO2 levels down as a definition of intelligence.
But hey – looking up at all the stars and thinking it’s a big lonely universe? So 2011. Now look up and picture all shapes and sizes of intelligent beings looking back at you from all directions. There, that feels better doesn’t it? But I wish there was more intelligence here too.