NASA's Mars rover Curiosity has detected the largest amount of methane yet measured during its seven years on the Red Planet. It's a particularly riveting discovery because the methane levels discovered by the rover are about three times higher than previous detections, leading to some speculation the gas may be biological in origin.
A report by The New York Times on Saturday first revealed the curious finding after obtaining an internal email from Ashwin Vasavada, a project scientist on the mission. On Sunday, NASA released a statement confirming the discovery, explaining how Curiosity's Sample Analysis at Mars (SAM) suite of instruments had detected methane at 21 parts per billion units by volume -- much higher than ever before.
Methane is an important molecule for microbes on Earth, and its detection on another planet has led to speculation that tiny microbes are (or were) puffing gas out at such a rate that NASA's intrepid rover can spot them.
Scientists havein the past, including as far back as the Viking missions in the 1970s. Thus, the discovery of more methane doesn't necessarily mean we've stumbled upon life. Moreover, spikes in Mars' methane levels aren't unusual, with in the molecule's atmospheric concentration. So where has this particular methane come from? The simple answer is: We just don't know yet.
"There are a few different ideas that have been put forward to explain things which include both biological and non-biological mechanisms," said Jonti Horner, astrophysics professor at the University of Southern Queensland, Australia.
"It isn't quite a smoking gun for life just yet."
Thomas Zurbuchen, associate administrator of NASA's science mission directorate, has cautioned on Twitter against jumping straight to the ET solution, noting methane can be created by geological processes. And sadly, as far as we know, rocks are not living beings.
Curiosity now has some extra work to do, with a follow-up experiment being conducted over the weekend "to gather more information on what might be a transient plume," said NASA. The agency notes these unusual methane spikes have been picked up before, but we're not really sure how long they last or what might be causing them. Results from the additional experiment could reach us as early as Monday, according to the Times.
However, the agency notes Curiosity does not contain instruments that can definitively say where the methane may have come from.
"With our current measurements, we have no way of telling if the methane source is biology or geology, or even ancient or modern," said Paul Mahaffy, SAM principal investigator, in a statement.
Good science relies on follow-up and repeat findings before confirmation, so while it's easy to get excited by the potential for signs of life, a lot more work needs to be done before we can truly confirm the presence of any tiny, underground martian friends.