If life did ever exist on Mars, some scientists think life on Earth might be related. Calling it "panspermia," they say . For example, spores contained in one of hundreds of thousands of Martian meteorites that have fallen to the Earth may have sprouted into life long ago. On the other hand, Martian microbes the rover finds could have come from Earth, although it's a less likely scenario.

Ultimately, however, any relational link between life on the two planets could be confirmed if Martian life is coded in DNA, as ours is, although because DNA breaks down over time the Curiosity would need to find newer or alive microbes for scientists to make such a determination.

One thing is certain: Finding microbial life on Mars would elicit great debates regarding the origins of life.

If Curiosity doesn't make it to the surface of the red planet intact, the future of NASA's Mars  program could be in danger.