Three Generations of Rovers are pictured in the Mars Test Yard at NASA's Jet Propulsion Laboratory, Pasadena, California in this undated handout photograph. Front and left is the flight spare for the first Mars rover, Sojourner, which landed on Mars
Three Generations of Rovers are pictured in the Mars Test Yard at NASA's Jet Propulsion Laboratory, Pasadena, California in this undated handout photograph. Front and left is the flight spare for the first Mars rover, Sojourner, which landed on Mars in 1997 as part of the Mars Pathfinder Project. The Mars Exploration Rover Project test rover (L) that is a working sibling to Spirit and Opportunity, which landed on Mars in 2004 and shown (R) is a Mars Science Laboratory test rover the size of that project's Mars rover, Curiosity, which is on course for landing on Mars on August 5, 2012. REUTERS/NASA/JPL-Caltech/Hando

On Dec. 16, NASA made an announcement that the Mars Curiosity Rover had detected spikes of methane in the air of Mars. Methane is a gas that, on Earth, comes mainly from life, meaning that when animals eat food, it comes out as waste gas.

The finding of the Mars Curiosity Rover immediately led to speculation that life might be the source of the gas as it is on Earth. An article by The Guardian suggested it might and that communities of microbes could be living under the surface that was letting out the gas. The article also suggested corpses of extinct bugs in the interiors of the Red Planet could be heating up and were being vaporised into methane. It was found that the gas was present in Earth 4,000 times more than that in Mars. In the atmosphere of the Red Planet, the gas was present at around 1 part per billion.

Dr Chris Webster from the Jet Propulsion Laboratory of NASA in California said that their observations were evidence for production of methane on the Red Planet and could not directly provide evidence of microbial life. He added that they could not rule out the possibility that low background level, as well as high methane levels, originated, in part, from microbial activity.

Michael New, an astrobiologist at the headquarters of NASA in Washington DC said that one needs to know a lot more about what was going on at the source. He said that one needed to know the context, and it was hard to look at just the methane and claim that it came from life.

In 2009, methane was first detected on Mars by NASA when telescopes picked out the features of the gas. The finding showed evidence of a replenishing supply of methane on the Red Planet, which survived only a span of 340 years in the air on Mars. After which, it was broken down by sunlight.

Like there are many speculations of life on Mars currently, back in 2009, the situation was the same. There was constant debate regarding the prospect of life forms after the findings of the 2009 methane plumes.