General Discussion
In reply to the discussion: The universe is much bigger than big [View all]cthulu2016
(10,960 posts)Last edited Fri Sep 28, 2012, 04:10 AM - Edit history (1)
The smallest outside planet we have deduced the existence of from observation is still larger than Earth. But nobody would cite that fact as seriously suggesting that our solar system may be unique in having such small rocky inner planets like Earth, Mars, Venus and Mercury.
The numbers are such that the idea of anything in our solar system being unique in the universe approaches zero unless we can identify something singular about the conditions here.
We have no evidence of life elsewhere but we do have some evidence of is that the laws of nature are universal, the periodic table of elements here is the same as the periodic table in the andromeda galaxy, stars everywhere produce pretty much the same elements... that there is nothing local about the base necessities of life.
Our best scientific understanding of the cosmos is that liquid water exists on billions of billions of other planets. (And does not exist on billions and billions of others.) Hydrogen and carbon are plentiful on billions of billions of other planets with liquid water.
And given billions of years of collisions and combinations of a zillion to the zillionth power hydrogen and carbon molecules something is going to develop either metabolism or inheritability, and then develop the other.
Keep in mind that if life hadn't developed here when it did then it could have the next day, and the next, and the nest. For billions of years. (Without micro-organisms to eat them, the seas would still be a literal soup of hydrocarbons every day of that billions of years.)
Life will happen time and time and time again. It's not really an unusual process.
One of the coolest developments of the post DNA discovery era is the realization that there was nothing extraordinary about the development of life here.
As for intelligent life, the same applies. If man hadn't come along when we did then we could come along a billion years from now.
The number of planets with life will probably far outnumber those with any sentient life, so the intelligent life planets may be in the billions, rather than the trillions that must surely have life.
But given all of that, it is possible and perhaps even likely that we will never exchange information with an extraterrestrial sentient species.