On the 2,440th Martian day at Gale Crater, the Curiosity rover detected a large spike in the presence of the gas methane. It was by far the largest plume detected by the rover, and parallels an earlier ground-based discovery of an even larger plume of the gas. (NASA, JPL-Caltech, MSSS)
The presence — and absence — of methane gas on Mars has been both very intriguing and very confusing for years. And news coming out last week and then on Monday adds to this scientific mystery.
To the great surprise of the Curiosity rover team, their Sample Analysis on Mars instrument sent back a measurement of 21 parts per billion of methane on Thursday — by far the highest measurement since the rover landed at Gale Crater.
As Paul Mahaffy, principal investigator of the instrument that made the measurement, described it yesterday at a large astrobiology conference in Seattle, “We were dumbfounded.”
And then a few days later, all the methane was gone. Mahaffy, and NASA headquarters, reported that the readings went down quickly to below 1 part per billion.
These perplexing findings are especially important because methane could — and also could not — be a byproduct of biology. ...