Scientists have finally confirmed something they had doubted, that Mars does occasionally emit puffs of methane into its atmosphere. That doesn’t necessarily mean what you presume it means, that the Red Planet is or once was home to alien cows or other forms of life. But it could.
Most of the methane on Earth is pumped out by microbes and other living creatures — most notoriously cows, which emit vast clouds of the greenhouse gas (though largely by burps, contrary to popular lore). So while sniffing methane may not be so thrilling on Earth, discovering that Mars is burping up the stuff — following confirmation that there is water below its rusty surface — fits a critical piece in a most intriguing puzzle.
Searching for life on Mars, or getting there, has obsessed earthlings ever since telescopes enabled them to spy on the neighboring globe. The passion persists. The methane report last week, from scientists working for the European Space Agency’s Mars Express orbiter, was followed by a statement from NASA Administrator Jim Bridenstine that the agency hopes to send astronauts to Mars by 2033. One way or another, the rusty dot of twilight is getting awfully lively.
The notion of Martian life gained popularity and respectability when Percival Lowell, a well-regarded scientist who founded the Lowell Observatory in Arizona, spent 15 years gazing at Mars at the close of the 19th century and came up with detailed maps of canals and oases, positing that they had been built by a civilization desperately tapping its last source of water as the planet dried up. That helped spur a rich Martian sci-fi literature, including such classics as C.S. Lewis’ “Out of the Silent Planet,” in which a dying Mars is populated by intelligent species that choose to become extinct rather than invade Earth.
Sadly, science eventually quashed the Lowellian vision of intelligent life-forms digging ditches to delay their end, though it’s something earthlings might ponder as they relentlessly accelerate their planet’s doom by pumping carbon dioxide and other climate-altering gases (including methane) into the atmosphere. But if there are no canals or oases on Mars, there is liquid water, the sine qua non of life as we know it, and something burping up methane, a signature, though not a proof, of life.
The former was confirmed in July when Italian scientists working for the Mars Express mission reported that they had detected a 12-mile-wide underground liquid pool near the Martian South Pole. And now the same team of scientists has confirmed earlier readings of wafts of methane by measurements from the Mars Express orbiter and from NASA’s Curiosity rover.
Neither is proof of life. The lake was probably too salty to freeze, and therefore too salty for life, and methane can be produced by geological processes, or it could have been produced eons ago and trapped under ice. So the search goes on. But at least scientists have pinpointed where the gas is coming from, which is within the Gale Crater, near the Martian equator, where the Curiosity rover is still actively sniffing and sifting for microbial life.
That might be a good spot for NASA’s astronauts to start their explorations, perhaps scoping sites for the canals and oases desperate earthlings will need when they flee their overheated planet. In the meantime, the European Space Agency invites all “citizens of planet Earth” to compete for a 30-second audio file that will be played on Mars in an experiment planned for the ExoMars 2020 mission. The file will also be broadcast on Earth, so the Czech organizers urge a message “valid for the world today.”
This article originally appeared in The New York Times.