NASA Curiosity Rover Finds No Methane on Mars: Hunt for Life Continues

NASA's Curiosity rover continues to reveal more and more about Mars as it treks across the rocky surface. Now, it's shown that the Martian environment lacks methane. This surprising finding flies in the face of previous data reported by U.S. and international scientists.

Methane is a good indication that there's life on a planet. While it's certainly possible that the gas can be produced without biology, the presence of it would have helped direct efforts for the hunt for life on the Red Planet. The fact that methane isn't present, though, seems to show that there are no methane-producing Martian microbes.

In order to actually detect whether or not there was methane on the Red Planet, Curiosity analyzed samples of the Martian atmosphere six times from October 2012 through June. Using the Tunable Laser Spectrometer, the rover should have been able to detect traces of methane in the atmosphere. Instead of methane, though, Curiosity found a lack thereof. Current readings reveal that the amount of methane in the atmosphere today must be no more than 1.3 parts per billion, which is about one-sixth as much as some earlier estimates.

In the past, researchers reported that they encountered localized methane concentrations of up to 45 parts per billion on Mars. This in particular sparked the interest of scientists since it seemed to indicate that there may be some kind of biological source. These estimates, though, were based on observations from Earth and from orbit around Mars.

"This important result will help direct our efforts to examine the possibility of life on Mars," said Michael Meyer, NASA's lead scientist for Mars exploration, in a news release. "It reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don't generate methane."

Currently, researchers estimate that the highest concentration of methane that could be present without being detected by Curiosity's measurements would amount to no more than 10 to 20 tons per year entering the Martian atmosphere. That's about 50 million times less than the rate of methane entering Earth's atmosphere.

The findings are important for better understanding Mars and the processes that occur on the Red Planet. In addition, the lack of methane indicates that looking for methane-causing microbes is a dead end. Instead, scientists should concentrate in other areas when it comes to the hunt for alien life.

The findings are published in the journal Science.