Earth having sex with MarsYep, that's not too farfetched. Just one of the things that came up during The Long Now Foundation's (TLNF) seminar about the asteriod threat in the next 100,000 years. Its based on the idea that pieces of rock from both planets (as an effect of asteroid explosions) containing living organisms that could survive in space, could have seeded life from Mars to Earth, from Earth to Mars, or maybe cross polination perhaps?
Lots of other interesting stuff on TLNF's website. Basically stuff that needs long term thinking. The seminar topics are distributed in audio (mp3) form, and can be downloaded for free.
Its nice to have something like these to ponder from time to time. It gives one a different perspective about current life problems. Problems bigger than our own, bigger the our country. Heck, its not even global, like the asteriod threat, its universal! A problem every living organism in the universe would inevitably face. Resistance is futile.
Interestingly, the solution to the asteriod threat brings about huge ethical and moral implications. For example, if we only focus on blasting every threat in space, it could very well be the an excuse to build nuclear weapons in space (which might have a greater chance of endangering the human race). Also, if all we can do is deflect an asteriods path, who decides which place on earth should take the impact. Let alone who decides if the public should know if such a threat is detected in advance. Imagine the panic and pandemonium upon hearing your local station announcing an extinction level event.
The threat is very real tho. And we don't have the capability yet to monitor space effective enough to have realiable early warning protocols in place. A direct impact of 200 kilometer sized asteriod is enough to wipe out the human race and force another evolution. The ocean would boil, for some time the sun would not be able to penetrate the atmosphere, and a lot more armageddon like scenarios.
The good news is, its not likely to happen anytime soon. Nobody can predict the future. Its just one of those things that would be nice to think about during a star starry night.