Rather depressing news for science. The big giant robot Curiosity on Mars has been scouring the surface of Mars as part of missing to find sign of life including digging up ancient rocks and so on. Looking for methane gas was one on the todo list, but so far found none! nothing! so does this mean no life ever supported or existed on mars?

http://news.discovery.com/space/mars-missing-methane-curiosity-rover-msl-130919.htm#mkcpgn=fbdsc8

curiosity rover on mars as of today found no sign of methane gas does this mean no life ever existed or will ever be?