Is Alien Life Hiding Beyond Earth 2.0?
“It may be the case that life is rare in the Universe, in which case it will require us to look at a lot of candidate planets — possibly with very high precision — in order to reveal a successful detection. But if we search exclusively for planets that have similar properties to Earth, and we restrict ourselves to looking at parent stars and solar systems that are similar to our own, we are doomed to get a biased representation of what’s out there.
You might think, in the search for extraterrestrial life, that more is more, and that the best way to find life beyond Earth is to look at greater numbers of candidate planets that might be the Earth 2.0 we’ve been dreaming of for so long. But non-Earth-like planets could be home to life that we’ve never considered, and we won’t know unless we look. More is more, but “different” is also more. We must be careful, as scientists, not to bias our findings before we’ve even truly started looking.”
If we want to find life elsewhere in the Universe, it only makes sense to look at our own world, where we know it was successful, and to try and find other worlds similar to our own. But that absolutely cannot be the only thing we do, or the only inhabited worlds we’ll even have a chance at finding are the ones similar to our own.
We have many good reasons to favor or disfavor the probability of finding life on a variety of planets and moons out there in our galaxy, but the real truth of the matter is we don’t know how common or rare life is. We don’t know how common or rare a huge variety of processes are, or even whether life is more likely to arise under conditions very different from those we find on our own planet.