Last week, NASA’s Curiosity rover detected a belch of natural gas on the red planet. The gas has since dissipated, leaving only a mystery.
Mars gave a good burp last week, but the gas has come and gone, leaving scientists no closer to knowing whether there is life on or beneath the red planet.
Last Wednesday, scientists grew excited when NASA’s Mars Curiosity rover, while testing the air of Gale Crater, detected high levels of methane, which on Earth can be produced by microbes or other living things.
Curiosity’s keepers at the Jet Propulsion Laboratory, in Pasadena, canceled the rover’s weekend plans to repeat the experiment, hoping for clues that might point to the existence of life on the planet. But the second reading indicated that the methane had fallen to its normal level in the Martian air — less than one part per billion, all but nonexistent.
Only a few days earlier, the methane level had spiked to 21 parts per billion, according to the rover’s Sample Analysis at Mars experiment.
“A plume came and a plume went,” Paul Mahaffy, of NASA’s Goddard Space Flight Center, said on Sunday during a presentation at an astrobiology meeting in Bellevue, Wash.
“The methane mystery continues,” Ashwin R. Vasavada, a mission project scientist, said in a statement from the Jet Propulsion Laboratory, where Curiosity was built. “We’re more motivated than ever to keep measuring and put our brains together to figure out how methane behaves in the Martian atmosphere.”
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Methane, better known as natural gas, can be produced by microbes, including those that live in the guts of cows, or by purely geological processes. On Mars, sunlight and other chemical reactions should quickly destroy the molecule.
The fleet of robots orbiting and roving Mars has been on the lookout for methane, the breath of a possible something. And every once in a while, the planet has complied by emitting a puff of methane.
Scientists don’t know for sure where the gas is coming from or what is producing it. The first indications that methane was present in the Martian atmosphere came from telescopes on Earth and from Mars Express, a European Space Agency satellite launched in 2003. In 2013 both Curiosity and Mars Express registered a spike in methane up to 7 parts per billion that lasted at least two months.
But a more recent satellite, the European Trace Gas Orbiter, which arrived at Mars in 2016, has not reported any methane. And Mars Express, which passed over Gale Crater the same day as Curiosity saw its recent spike, has not yet reported its own results from that day, although scientists working with both spacecraft say they will complete analysis of recent measurements soon.
Kenneth Chang contributed reporting.
Earlier reporting on the Martian methane mystery
Dennis Overbye joined The Times in 1998, and has been a reporter since 2001. He has written two books: “Lonely Hearts of the Cosmos: The Story of the Scientific Search for the Secret of the Universe” and “Einstein in Love: A Scientific Romance.” @overbye