General Discussion
In reply to the discussion: New model predicts that we're probably the only advanced civilization... [View all]StevieM
(10,500 posts)and then re-enter at a different part of it. If there is a multi-verse than maybe that isn't a totally irrational prospect.
I personally believe that sexual reproduction is necessary in order to have plants and animals. And I think that doesn't happen nearly as often as simple life. In other words, simple life, like microbes, is probably fairly common. But getting to the point where we have sexual reproduction, plants and animals is a lot less common. Maybe it happens on one planet in one out of 10 million galaxies.
If there are 200 billion galaxies in the universe than that means that it happens on 20 thousand planets across the universe. And I suspect that most of those planets never get hit by a perfectly-sized asteroid in the worst possible place. So they are probably dominated by dinosaur-type creatures.
Maybe there are primate-type creatures on 100 of them. I am not sure how often the primates come down from the trees.
Of course, they are now saying that there may be 2 trillion galaxies. So numbers are always being updated.