are we alone in the universe?

[KenWittlief]

Originally Posted by sanddrag

Wait a minute. Homo sapiens didn't arrive here from another planet. They evolved here beginning with single celled organisms (or so we think). Or maybe I misunderstood you. Are you saying that perhaps homo sapiens perhaps evolved somewhere else and then that "somewhere else" started life in it's most basic forms here on Earth and then it evolved into us?

if there are 10,000 earth like planets in our galaxy, then the odds are 1:10,000 that any given planet is the single origin of life

if we came here from somewhere else, then either we were involved in that transfer (as a species) or it was done by a species more evolved than us, and we were just cargo along for the ride.

But I think if we were going to colonize another star system, I cant think of any reason to send only one-cell organisms. I would send the most complex life forms we could, including humans if humans can survive on the new world.

so from what we know about earths biological history - tens of millions of years of life existed before humans showed up. Therefore, if we came here from somewhere else there must have been a very long program of first seeding the planet with plant and animal life, and then after 50 million years or more we came here too (after the earth was ready) ?

We only assume humans evolved from other lifeforms here on earth, because there is no other explaination based on what we have found here on earth. But if we came here from another world, then we dont know our own history as a species

which would be very strange.

we dont really know. Unless we find a starship buried under the pyramids Im inclined to believe we evolved here, and we are the only life in the galaxy.