The definitive discovery in Mars’ atmosphere of methane — often, but not always, a compound hinting at life — introduces the possibility of underground organisms.
A paper from yesterdays edition of Science raises some intriguing possibilities that underground 'microbes' may be producing methane on Mars. Or maybe it's just a natural phenomenon:
About 0.6 kilograms of methane emerge each second in the summer, Mumma said, which is comparable to the emissions from a natural oil seep near Santa Barbara, California.
Thirty six years later and we still don't know if there is Life on Mars.