[PatrickHenry]

Rare Earth now seems more likely... for its unlikely causal chain

Yes, that's a lot of things that need to fall into place; but with the Hubble telescope, we've recently discovered that the presence of planetary systems is far greater than was previously supposed. So I don't know if the overall number of planets we deem suitable for life is now supposed to be small or what. My very rough guess is that the "rare earth" factors are cancelled out by the "abundant planetary systems" factor. So maybe we're back where we were when Sagan estimated there might be thousands of intelligent species in our galaxy at any one time. If he were around today, it might still be his estimate. Or it might not ...

[edwin hubble]

"My very rough guess is that the "rare earth" factors are cancelled out by the "abundant planetary systems" factor. "

Yes... It is interesting while our further studies of Earth make it seem rarer and rarer (just because of a whole string of 'unique' phenomena), at the same time the sheer number of 'terrestrial' planets seems to grow at an explosive rate.

Most will be like either Venus (dry) or Mars (cold). For the 'just right' orbit some may have higher life forms.

I think of the 'intelligent alien' here on Earth, the octopus.

My hope and wish is for many (peaceful and wise) life forms, of course. Carl Sagan's writing and his 'billions and billions' lured me to my line of work decades ago.