I read this MSN.com article Earth's Twin. It was really interesting.
A quick summary: Scientists are really close (like 5 or so years) to finding a planet that is supposedly exactly like Earth. They have already found 3 "super Earths". Which basically means that the planets are bigger than our Earth but small enough to have mountains. Scientists have already found multiple Jupiters and Saturns and are close to having the technology to find smaller planets like Uranus and Neptune.
Taken from the article: "We are looking for twins of the Earth, analogs that walk and talk and smell like our own Earth," Marcy said during a telephone interview. He is currently looking for super-Earths using the W.M. Keck Observatory in Hawaii.
Such a twin would be rocky, with a similar chemical composition to Earth, and would orbit within the habitable zone of its star.
The habitable zone defines the distance at which a planet must orbit from its star for liquid water to exist on its surface — not too hot like Venus, not too cold like Neptune or Pluto.
Astronomers have found planets orbiting pretty close to the habitable zone, but none so far within it.
"I suspect there are Earth-like planets with lakes and rivers and waterfalls and deep glacial gorges and that are spectacularly beautiful," Marcy said.
Finding a planet in the habitable zone is the first step toward finding alien life.
"When we say it's a habitable world, all we're doing is saying it potentially could hold life," Boss said. "To go beyond that to say, 'Here's a habitable world; is it inhabited,' then you need to start studying the atmosphere of the planet."
Ok, science lesson over.
This seriously freaks me out. Maybe I have ready too many Stephen King or Dean Koonce stories and watched too many Sci-Fi movies. Maybe? Hell, probably.
I think we need to leave the other planets alone. Messing with "alien life" is only asking for problems. I don't see things turning out well.
Its like poking a strange dog through the fence. You might get bitten, you might not. It really isn't a chance that I am willing to take.
And for anyone who is thinking "Oh but we could use the other planet's natural resources", stop right there. Why even consider destroying another planet? We have done enough damage on our OWN planet.
18 hours ago