Earthlings produce methane burps as a waste gas, but how did such burps happen to float on Mars? Were they produced by bacteria? Or by angry green men?

It is not clear. But the NASA vehicle earlier found water too on Mars. All these seem to indicate that life exists on Mars. 

Dr Paul Mahaffy of NASA says that the methane spikes are 'transient'. "We don't want to eliminate anything, and potentially it could indicate life or evidence of ancient methane trapped which could show ancient life ... But it's interesting to think about why it comes and goes. It seems to be suggestive of a localised source," he explains.

The Rover needs to test isotope levels in order to gauge whether the  emissions were sent from a biological source or not. Curiosity's Tunable Laser Spectrometer used "intense light" to conduct chemical analysis and take fas samples. 

The readings were taken over the 300-square-metre area over two months. It was increased 10 times, yet when the Rover travelled by one more kilometre, the higher methane levels disappeared.

Dr Chris Webster, an American scientist from the agency's Jet Propulsion Laboratory in Pasadena, California, conducted the study. 

Another interesting space rock was also discovered on Oct 27 and it was composed of various "different materials" from the environment. The ChemCam laser helped NASA to collect information on the rock and its composition.