This is, perhaps, one of the most exciting things I will ever read. Scientists may have discovered life on Mars. Methane is an important chemical in biological systems, and breaks down in the local enviroment (of mars) after about 300 years. So if geological processes such as volcanos, haven't been actively adding methane to the atmosphere in the last few hundred years (we think Mars has been volcanicly dormant for a very long time), then something else must be releasing the gas. That something is likely bacteria.

Needless to say, the discovery of extra-terrestrial life, in any form, will have a profound impact on science. If life on mars is the result of a second genesis, we could have the unique opportunity to study biology from a new angle. I can hardly imagine the sort of discoveries this could lead too.....