I love scientific speculation. Exactly how do they know Mars looked like Earth 4 billion years ago? Its as speculative as the noises the dinosaurs made in Jurassic Park.
Agreed!
So do I. This brings up the question of if there was life on Mars, and Mars was much like the US is now, could life on Earth be something that originated on Mars? Since we can imagine and perhaps someday mankind can achieve terraforming another planet, there is no logical reason that we couldn't be the result of terra-forming.
I'm not saying it's true. It's speculative, and becomes more possible with findings like lots of planets in the universe and previous life on Mars.
I also love the classic Science Fiction writers. It's really interesting, not just their predictions, but their understanding of the nature of man.