A pair of NASA scientists told a group of space officials at a private meeting here Sunday that they have found strong evidence that life may exist today on Mars, hidden away in caves and sustained by pockets of water. --Space.com

The evidence is indirect and inconclusive. There are plenty of alaternative explanations for the methane signatures researchers are reporting. We are all ingrained with the idea that "extraordinary claims demand extraordinary proof." And yet, even the flimsiest evidence of extraterrestrial life is enough to excite the imagination of the scientific community.

Humanity, for good and for ill, has always had a curious drive to explore and discover. Whether crossing a desert, a jungle or an ocean, explorers sought to see just a little bit more than others had seen.

In our recent history, discoveries have been largely of smaller and smaller things with big implications: genes, DNA, molecules, atoms, protons, electrons and quarks. These are important but do not inspire a sense of wonder outside of a specially trained elite group of scientists.

If we are ever to discover life elsewhere in the universe, I've always believed that it would be fairly simple: a bacterium for example. But finding life -- any form of life -- on Mars or elsewhere would turn my perception of the universe upside-down.

There is a certain existential lonliness in being part of the only known living planet in the universe. Looking up at a starry sky on a winter night makes one feel small and alone. Yet somehow, finding merely a small microbe in space somewhere would be comforting, even if it deflated our own perceived importance.