Curiosity Explores 'Teal Ridge:' This image was taken by the left Navcam on NASA's Curiosity Mars rover on June 18, 2019, the 2,440th Martian day, or sol, or the mission. It shows part of "Teal Ridge," which the rover has been studying within a region called the "clay-bearing unit." Image Credit: NASA / JPL-Caltech. Full image and caption ›
Updated at 5 pm PDT (8 pm EDT) on June 24, 201
Curiosity's team conducted a follow-up methane experiment this past weekend. The results came down early Monday morning: The methane levels have sharply decreased, with less than 1 part per billion by volume detected. That's a value close to the background levels Curiosity is seen all the time
The finding suggests last week's methane detection – the largest amount of the gas Curiosity has ever found – was one of the transient methane plumes that have been observed in the past . While scientists have seen the background levels rise and fall seasonally, they have not found a pattern in the occurrence of these transient plumes. "The methane mystery continues," said Ashwin Vasavada, Curiosity's project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. "We're more motivated than ever to keep measuring and put our brains together to figure out how methane behaves in the Martian atmosphere."
Curiosity doesn't have instruments that can definitively say whether the source of the methane is biological or geological. A clearer understanding of these plumes, combined with coordinated measurements from other missions, could help scientists determine where they're located on Mars.
Curiosity's most recent methane findings will be announced during a live stream of the 5 p.m. PDT / 8 p.m. EDT NASA Town Hall at AbSciCon 2019, an astrobiology science conference event in Bellevue, Washington. Watch the plenary broadcast at:
Original story posted June 23, 2019
Curiosity Detects Unusually High Methane Levels NASA's Curiosity Mars rover found a surprising result: the largest amount of methane ever measured during the mission – about 21 parts per billion units by volume (ppbv). One example is that if you take a volume of air on Mars, one billionth of the volume of air is methane.
The finding came from the rover's Sample Analysis at Mars (SAM) tunable laser spectrometer. It's exciting because microbial life is an important source of methane on Earth, but methane can also be created through interactions between rocks and water.
Curiosity doesn't have instruments that can say what the source of the methane is, or even if it's coming from a local source within Gale Crater or elsewhere on the planet.
"With our current measurements, we have no way of counting if the methane source is biology or geology, or even ancient or modern," said SAM Principal Investigator Paul Mahaffy or NASA's Goddard Spaceflight Center in Greenbelt, Maryland.
The Curiosity team has detected many times over the course of the mission. Previous papers have documented how background levels of the gas seem to rise and fall seasonally. They have also noticed sudden spikes of methane, but the science team knows very little about how these transient plumes are different from the seasonal patterns.
The SAM team organized a different experiment for this weekend to gather more information on what might be a transient plume. Whatever they find – even if it's an absence of methane – will add context to the recent measurement.
Curiosity scientists need time to analyze these clues and conduct many more methane observations. They also need time to collaborate with other science teams, including those with the European Space Agency's Trace Gas Orbiter, which has been in its science orbit for a little over a year without detecting any methane. Combining observations from the surface and from orbit could help scientists locate the gas on the planet and understand how long it lasts in the Martian atmosphere. That might explain why the Trace Gas Orbiter's and Curiosity's methane observations have been so different.
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