In findings that are as scientifically significant as they are crushing to the popular imagination, NASA reported Thursday that its Mars rover, Curiosity, which has been trundling across the red planet for a little over a year, has deflated hopes that life could be thriving on Mars today.
The conclusion, published in the journal Science, comes from the fact that Curiosity has been looking for methane, a gas that is considered a possible calling card of microbes, and has so far found none of it. While the absence of methane does not entirely preclude the possibility of present-day life on Mars, it does return the idea to the realm of pure speculation without any hopeful data to back it up.
“You don’t have direct evidence that there is microbial process going on,” as Sushil K. Atreya, a professor of atmospheric and space science at the University of Michigan and a member of the science team, put it.
The history of human fascination with the possibility of life on Mars is rich, encompassing myriad works of science fiction, Percival Lowell’s quixotic efforts to map what turned out to be imaginary canals, Orson Welles’ panic-inducing 1938 “Attack by Mars” radio play, and of course Bugs Bunny’s nemesis Marvin the Martian.
But NASA scientists are going strictly by their data, and they are having none of it. Asked the same question once posed by David Bowie — “Is there life on Mars?” — John Grotzinger, the project scientist for the Curiosity mission, would only go so far as to say that the lack of methane “discounts” the possibility of living creatures going about their business on Mars.
“It does diminish the argument that there are methanogenic organisms there,” Dr. Grotzinger said.
A decade ago, observations from telescopes on Earth and a spacecraft orbiting Mars suggested that vast plumes of methane were rising from certain regions, but Curiosity’s readings now bring the earlier claims into question.
“It just isn’t there,” said Dr. Atreya, referring to methane.”
– The New York Times, "Mars Rover Comes Up Empty In Search for Methane"
HOW MARS GOT ITS GROOVES BACK Dubbed linear gullies, these long grooves appear on the sides of some sandy slopes during Martian spring. They have nearly constant widths, extend for as long as two kilometers, and have raised banks along their sides. Unlike most water flows, they do not appear to have areas of dried debris at the downhill end. A leading hypothesis — actually being tested here on Earth — is that these linear gullies are caused by chunks of dry ice breaking off and sliding down hills while sublimating into gas, eventually completely evaporating into thin air. Or, there are aliens. Aliens on Mars. And these are the tracks of their peers. (Photo: HiRISE, MRO, LPL (U. Arizona) via NASA APOD)
TRACK ONE A boulder leaves behind a trail as it rolls down a slope in the Nili Fossae region of Mars. The image was captured by NASA’s orbiting Mars Reconnaissance Orbiter. It is unclear what set the boulder on its downhill trajectory. (Photo: NASA via NBC News)
DICKS IN SPACE No, the NASA rover Curiosity did not draw a penis on the surface of Mars. However, Curiosity'smission controllers should probably refrain from having the probe make K-turns from now on, lest they elicit giggles from the same group of little boys who think the Valles Marineris looks like a vagina. (Via the Herald Sun)
PROBE-LEM A self-taken photomosaic of the rover Curiosity taken in February. The NASA probe had been all but shut down for the past three weeks as engineers with the space agency figured out what caused both onboard computers to shut down. Off the record: the Klingons did it. (Photo: NASA via Reuters / The New York Times)
A panoramic view of the NASA rover Curiosity, stitched together from several self-portrait shots taken in the Yellowknife Bay section of the Gale Crater on Mars. Click through for larger… and lonelier. (via NASA APOD)
NOT BRUNO MARS NASA’s Mars rover Curiosity is pictured in this self-portrait, stitched together from dozens of photos taken by the rover’s Mars Hand Lens Imager (MAHLI). Curiosity is atop a flat outcrop called John Klein, which will serve as the first site for the rover’s rock-drilling activities. (Photo: NASA via The Telegraph)
SEA OF TRANQUILITY A panoramic image of Point Lake on Mars, taken by the NASA rover Curiosity in November. (via NASA APOD)