The scientists published their findings in Science. One of the co-authors, planetary scientists Michael Mumma, said:

The fact that we have found three discrete regions where Mars is releasing methane at this time means we have a window into processes occurring under the surface of the planet. The production (of methane) is likely due to only one of two possibilities. The first is geochemistry, the second is biology. That raises much interest on which one is the dominant production mechanism. [If it's geochemical in origin] we might expect the methane to be released only under regions that are volcanic districts. On the other hand, there could be biology that's going on either very near the surface or deep below the permafrost layer.

And with that simple phrase "there could be biology that's going on," we have our first admission - based on hard evidence - that there's a strong likelihood that life exists on Mars.

Most methane on Earth is released from biological organisms, which is why scientists speculate that the same might be true on Mars. But don't start getting excited about Martian cows. If there is life creating this methane on Mars, it's probably microbial life beneath the planet's surface, where liquid water exists.

One thing is for certain: This methane is coming from a source that renews it continuously. Researchers have been monitoring methane plumes on the planet's surface via satellite for five years. That means that it's either caused by seasonal volcanic activity, or the seasons in the lives of a creature or creatures.

Researchers not involved in NASA's study have confirmed that these findings are quite plausible, and nobody has yet ruled out the idea that the methane might be signs of life under the Martian permafrost.

SOURCES:

Science Journal

BBC News

After digging up a few teaspoons of Martian soil, Phoenix ran some chemical analyses. It baked some soil to see what gases were given off, and found a puff of oxygen. That could mean a few different things, but one of the possibilities is that the soil contained perchlorate salts, which are made of oxygen and chlorine molecules. That's interesting because perchlorates can act as food for some microrganisms and are a byproduct of some plant life processes.

So why is NASA so ambivalent about this discovery? For one thing, they didn't detect any chlorine yet, so they aren't sure if they really found perchlorates at all. And even if they did, the presence of perchlorates is not evidence of prior living organisms, and neither does the it preclude prior living organisms. What is unusual is that NASA chose to reveal details of an ongoing scientific investigation before they had really confirmed anything. Are they just feeling the pressure from the public relations department, or are they stalling until they're ready for the big reveal? Image by: NASA.

Martian Life Or Not? NASA's Phoenix Team Analyzes Results. [Science Daily]