Past, Present, Future?

I've already established that I'm a geek, and that I wonder about odd things. SO - this post should really come as no suprise.

Okay - I was watching some show on the Science Channel (getting a free preview this month, yay!) about the inside of the earth, and it was discussing the core and the magnetic field and how ours is alive and hot, but Mars' core is cold.

It went on to discuss how Mars had a hot core at one time, and most likely had a good magnetic field, which could then support an atmosphere, water, all that good stuff.

Then I was thinking about Venus, and about how it makes me think of how scientists describe very early Earth - you know, hot, volcanic, violent and hostile to life as we know it (it wasn't until photosynthesis began to occur on Earth that we had a large percentage of oxygen in the atmosphere).

All that led me to thinking - what if Mars was first, maybe it supported life, maybe even sentient life, and then the planet died, along with everything on it.

Now *we're* in the "goldilocks zone" where everything is perfect for life - but we know that eventually the core will cool and we'll be as dry as Mars. What if Venus is next? Maybe, even as we speak, the wheels are turning and life is making way?

Maybe, in the distant future, astronauts from Venus will land on Earth in search of evidence of water - and ponder the possibility of ancient life on Earth?