After all, Mars once boasted liquid water in great abundance - and water is a crucial component for life. According to Zubrin, if life is indeed a natural, chemical development wherever liquid water, reasonable temperatures and various minerals occur, then why shouldn't it appear on Mars?
"If we can go to Mars and find evidence of past life, then we will have proven that the development of life from chemistry is a general phenomenon in the universe," Zubrin says.
Such a discovery would change the way we look at the night sky. Every exoplanet positioned appropriately to its central star would be a potential hot spot for extraterrestrial life.
"If life will develop wherever it has a decent planet, it means that the universe is filled with life," Zubrin says, "And if life is everywhere, it means intelligence is everywhere. It means we're living in an inhabited universe. This is something that thinking men and women have wondered about for thousands of years, and we can find out the answer to this if by going to Mars."
Getting there, however, is going to take some serious commitment.
Three Weeks of War
"We've sent our first envoys, our robotic precursors to the red planet and gotten a taste of what it might be like to live there," Brown says. "But at the moment we're not prepared. Politically, we're not prepared."
Brown points out that Obama's reluctance to provide a firm Mars exploration time table reflects more than just the current state of the U.S. economy, but the lack of public enthusiasm and appreciation for manned Mars exploration.
"NASA's proposed budget for 2011 is $19 billion," Brown says. "That's about three weeks of the war in Iraq. So if we want to make sending humans to Mars a priority, it's merely a matter of political will. It's not a budgetary concern if all your constituents want it. We've just got to make sure that human exploration of Mars is an important subject for the American people."
Read "Terraforming Mars for the Greater Good" for Robert Zubrin's thoughts on interplanetary ethics.
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How NASA Works How Mars Works Image Source: NASA/WireImage/Getty Images