We could be about to discover that we really are not alone.
NASA's holding a news conference amid claims craft orbiting Mars have clouds of methane gas.
The evidence could point to life of some form on the Red planet, possibly organisms existing below the surface.
Some form of volcanic activity or unknown chemical reaction could also be the cause.
But even if the methane was produced biologically, it could be leaking from some ancient underground source from the far distant past.