Comment Re:it's only a matter of time... (Score 1) 186
"The fossil record goes how deep, exactly? About 100 million years is as far back as we know"
You should really do some research before posting. There's evidence of fossilised cyanobacteria from 3.5 billion years ago.
"multiply that again by how many galaxies are out there"
Again, probability doesn't work like that. The chance of a dice throwing 6 is 1/6. The chance of 2 dice both throwing a 6 is not 1/6 * 2, its actually less - 1/36.
While that's correct, we're not calculating the same odds:
The odds of rolling a 6 with one die is 1/6.
The odd of rolling a 6 with two dice rolls is 2 x 1/6 or 1/3.
This isn't quite right, it's actually 1 - (1 - 1/6) ^ 2 or 30.5%, not quite 1/3rd.
The odds of sentient life evolving once, somewhere, given one galaxy is the Drake equation result.
The odds of sentient life evolving once, somewhere, given our current estimate of 2 trillion galaxies in the know universe is the Drake equation result x 2 trillion...
so the odds there is another sentient species somewhere in the universe is 12 orders of magnitude higher than the odds we exist at all in just our own galaxy, which is pretty damn near close to 1.
For the astronomical calculation it would be 1 - (1 - [drake equation odds]) ^ 2 trillion