Mars is alive, according to Nasa scientists, who revealed the first 'definitive proof' of plumes of methane gas seeping from the surface. When methane was first found in the Martian atmosphere in 2003, some scientists claimed it could have been dumped on the planet by comets. But the latest discovery is proof that it is actually produced on the Red Planet. Professor Michael Mumma said last night the discovery of the gas meant there was a 'substantial probability that life was there or still survives' on our celestial neighbour.