Source: Discovery Channel Online

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Terraforming Mars

A few billion years ago, Mars may not have been all that much different from Earth. But something went awry, leaving Earth to live and its sister planet to die.

Now, as part of NASA's latest initiative to explore, explain and exploit space, scientists are beginning to discuss the tools and techniques for bringing Mars back to life.

From the pages of science fiction begins a new chapter in exploration ethics and human destiny: Whether humans can and should alter another planet to make it suitable for sustaining life.

The process is called terraforming and the people who are figuring out how to revive a planet like Mars are comfortably settling into the space agency's new multi-interest astrobiology program.

Could we? Should we?

Speaking at a recent astrobiology workshop at NASA's Ames Research Center in Mountain View, Calif., Future Shock author Alvin Toffler said he found the prospect of terraforming quite terrifying. "The macro-engineering projects that we have done in the past have frequently been disastrous. There's always more of what we haven't thought of than what we have thought of. We should be a little careful before we start terraforming other planets and think more deeply about how we terraform our own."

But that doesn't scare off scientists like Christopher McKay, a NASA planetary geologist based at Ames Research Center, who has written and spoken extensively on how to revive Mars.

"If we do leave the Earth, Mars is the logical first target," he says.

"There are some things on Mars we can't change, but there are some things we can. There's evidence that at one time it was a world where life could survive. It's probably all dead now, but the resources to make it alive are still there. This allows for the possibility of bringing Mars back to life," says McKay.

Step 1: Add water

The first step would be to reintroduce water to Mars. McKay and other scientists suggest melting the planet's frozen ice caps. The sun's energy would be the most efficient way to thaw Mars, but the planet would need to build up its atmosphere to keep the heat around long enough to do any good. The scientists propose releasing greenhouse gases, such as the chlorofluorocarbons (CFC) that are changing our own planet's environment, into Mars' atmosphere to trap the sun's heat and raise the planet's surface temperature. The source for the CFCs would be factories on Mars.

Eventually, Mars' melted ice caps would raise the planet's atmospheric pressure to about the level found at the tops of mountains on Earth. The first phase of terraformation would be complete in approximately 100 years.

The next step, which could take 100,000 years or so, would be to plant trees to remove carbon dioxide from the atmosphere and produce breathable oxygen.

Terraforming Earth

One of the strongest arguments for developing the engineering and technology to transform Mars is to save Earth. Critics who are uncomfortable with the idea of terraformation might be placated if the project helps heal the damage on Earth from pollution and deforestation. As a testing ground for scientists' theories on global warming, Mars would become more Earth-like. In turn, the research could help Earth become less like Mars.