NASA has been searching Mars up and down for signs of methane. Past findings had been hopeful towards the existence of the life-essential gas, but now the data looks grim.
"This important result will help direct our efforts to examine the possibility of life on Mars," Michael Meyer, NASA's lead scientist for Mars exploration said 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."
The Curiosity rover has tested the red planet for methane on six different occasions, but failed to find any evidence that Mars' atmosphere ever contained methane. The researchers estimated the amount of methane in the atmosphere (if any), couldn't be more than 1.3 parts per billion, about one-sixth of the amount they originally estimated. The highest amount of methane that could possibly be entering Mars' atmosphere is only 10 to 20 parts-per-billion. That is 50 million times less than Earth's methane intake.
"It would have been exciting to find methane, but we have high confidence in our measurements, and the progress in expanding knowledge is what's really important," lead author, Chris Webster of NASA's Jet Propulsion Laboratory, said. "We measured repeatedly from Martian spring to late summer, but with no detection of methane."
Methane is "the most abundant hydrocarbon in our solar system." And could hold clues to past life on the alien planet.
"There's no known way for methane to disappear quickly from the atmosphere," paper co-author, Sushil Atreya of the University of Michigan, said."Methane is persistent. It would last for hundreds of years in the Martian atmosphere. Without a way to take it out of the atmosphere quicker, our measurements indicate there cannot be much methane being put into the atmosphere by any mechanism, whether biology, geology, or by ultraviolet degradation of organics delivered by the fall of meteorites or interplanetary dust particles."
