Discovery Of Alien Inhabited Worlds

[Almighty Colin]

Cal,

How does that change anything? Even if we find billions of habitable planets it doesn't mean we'll find even one habited planet.

An example of the problem of abiogenesis. The organism with the smallest known genome, M. genitalium, has about 600,000 DNA bases. Bases can be A,G,T, or C. That is 4 to the 600000th power possibilities. That's about 10 to the 360k possibilities - more than the number of atoms in the universe by any stretch of the imagination. Getting that at random seems to be damned near impossible. So maybe the problem isn't as difficult as that? Maybe there is self-organization but we don't know that.

The possibility of life arising on a particular planet is (nearly) the possibility on one planet times the number of habitable planets (actually smaller). Even with trillions of planets that means hardly anything if the odds of it happening are 1 in something followed by more than 12 zeros. The odds of biogenesis occuring at random seem to be much lower than that.

We may take some very reasonable guesses about the second number, habitable planers, but how can we guess at the first?

Cal, you're discussing the possibility of habitable planets and I am discussing the possibility of habitated planets. I completely agree that it is extremely likely there are billions of habitable planets. That's a completely different question than whether life does exist in any of them. Just because there are trillions of places in the universe with a 50 yard long space doesn't mean there are any track events on them. Trillions of 50 yard tracks but no races.