{"id":10734,"date":"2024-04-22T12:03:35","date_gmt":"2024-04-22T16:03:35","guid":{"rendered":"https:\/\/zobi.alcowep.com\/bourtagshdrevxnls658739\/why-is-methane-seeping-on-mars-nasa-scientists-have-new-ideas\/"},"modified":"2024-04-22T12:03:35","modified_gmt":"2024-04-22T16:03:35","slug":"why-is-methane-seeping-on-mars-nasa-scientists-have-new-ideas","status":"publish","type":"post","link":"https:\/\/zobi.alcowep.com\/bourtagshdrevxnls658739\/why-is-methane-seeping-on-mars-nasa-scientists-have-new-ideas\/","title":{"rendered":"Why is Methane Seeping on Mars? NASA Scientists Have New Ideas"},"content":{"rendered":"

Why is Methane Seeping on Mars? NASA Scientists Have New Ideas<\/h2>\n

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5 Min Read<\/div>\n

\n\t\t\t\t\t\t\t\tWhy is Methane Seeping on Mars? NASA Scientists Have New Ideas\t\t\t\t\t\t\t<\/h1>\n<\/div>\n<\/div>\n
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Filled with briny lakes, the Quisquiro salt flat in South America\u2019s Altiplano region represents the kind of landscape that scientists think may have existed in Gale Crater on Mars, which NASA\u2019s Curiosity Rover is exploring.<\/figcaption><\/div>\n<\/div>\n
\n\t\t\t\t\t\tCredits: <\/span>
\n\t\t\t\t\t\tMaksym Bocharov<\/span>\n\t\t\t\t\t<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n

The most surprising revelation from NASA\u2019s Curiosity Mars Rover \u2014 that methane is seeping from the surface of Gale Crater \u2014 has scientists scratching their heads.<\/p>\n

Living creatures produce most of the methane on Earth. But scientists haven\u2019t found convincing signs of current or ancient life on Mars, and thus didn\u2019t expect to find methane there. Yet, the portable chemistry lab aboard Curiosity, known as SAM, or Sample Analysis at Mars, has continually sniffed out traces of the gas near the surface of Gale Crater, the only place on the surface of Mars where methane has been detected thus far. Its likely source, scientists assume, are geological mechanisms that involve water and rocks deep underground.<\/p>\n

If that were the whole story, things would be easy. However, SAM has found that methane behaves in unexpected ways in Gale Crater. It appears at night and disappears during the day. It fluctuates seasonally, and sometimes spikes to levels 40 times higher than usual. Surprisingly, the methane also isn\u2019t accumulating in the atmosphere: ESA\u2019s (the European Space Agency) ExoMars Trace Gas Orbiter, sent to Mars specifically to study the gas in the atmosphere, has detected no methane.<\/p>\n

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\n\t\tWhy do some science instruments detect methane on the Red Planet while others don\u2019t?<\/span>
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\u201cIt\u2019s a story with a lot of plot twists,\u201d said Ashwin <\/a>Vasavada<\/a>, Curiosity\u2019s project scientist at NASA\u2019s Jet Propulsion Laboratory in Southern California, which leads Curiosity\u2019s mission.<\/p>\n

Methane keeps Mars scientists busy with lab work and computer modeling projects that aim to explain why the gas behaves strangely and is detected only in Gale Crater. A NASA research group recently shared an interesting proposal.<\/p>\n

Reporting in a March paper in the Journal of Geophysical Research: Planets<\/a>, the group suggested that methane \u2014 no matter how it\u2019s produced \u2014 could be sealed under solidified salt that might form in Martian regolith, which is \u201csoil\u201d made of broken rock and dust. When temperature rises during warmer seasons or times of day, weakening the seal, the methane could seep out.<\/p>\n

Led by Alexander Pavlov<\/a>, a planetary scientist at NASA\u2019s Goddard Space Flight Center in Greenbelt, Maryland, the researchers suggest the gas also can erupt in puffs when seals crack under the pressure of, say, a rover the size of a small SUV driving over it. The team\u2019s hypothesis may help explain why methane is detected only in Gale Crater, Pavlov said, given that\u2019s it\u2019s one of two places on Mars where a robot is roving and drilling the surface. (The other is Jezero Crater, where NASA\u2019s Perseverance rover<\/a> is working, though that rover doesn\u2019t have a methane-detecting instrument.)<\/p>\n

Pavlov traces the origin of this hypothesis to an unrelated experiment he led in 2017, which involved growing microorganisms in a simulated Martian permafrost (frozen soil) infused with salt, as much of Martian permafrost is.<\/p>\n

Pavlov and his colleagues tested whether bacteria known as halophiles, which live in saltwater lakes and other salt-rich environments on Earth, could thrive in similar conditions on Mars.<\/p>\n

The microbe-growing results proved inconclusive, he said, but the researchers noticed something unexpected: The top layer of soil formed a salt crust as salty ice sublimated, turning from a solid to a gas and leaving the salt behind.<\/p>\n

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\n\t\tPermafrost on Mars and Earth<\/span>
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\u201cWe didn\u2019t think much of it at the moment,\u201d Pavlov said, but he remembered the soil crust in 2019, when SAM\u2019s tunable laser spectrometer detected a methane burst<\/a> no one could explain.<\/p>\n

\u201cThat\u2019s when it clicked in my mind,\u201d Pavlov said. And that\u2019s when he and a team began testing the conditions that could form and crack hardened salt seals.<\/p>\n

Pavlov\u2019s team tested five samples of permafrost infused with varying concentrations of a salt called perchlorate that\u2019s widespread on Mars. (There\u2019s likely no permafrost in Gale Crater today, but the seals could have formed long ago when Gale was colder and icier.) The scientists exposed each sample to different temperatures and air pressure inside a Mars simulation chamber at NASA Goddard.<\/p>\n

Periodically, Pavlov\u2019s team injected neon, a methane analog, underneath the soil sample and measured the gas pressure below and above it. Higher pressure beneath the sample implied the gas was trapped. Ultimately, a seal formed under Mars-like conditions within three to 13 days only in samples with 5% to 10% perchlorate concentration.<\/p>\n

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This is a sample of mock Martian regolith, which is \u201csoil\u201d made of broken rock and dust. It\u2019s one of five samples that scientists infused with varying concentrations of a salt called perchlorate that\u2019s widespread on Mars. They exposed each sample to Mars-like conditions in the Mars simulation chamber at NASA\u2019s Goddard Space Flight Center in Greenbelt, Maryland. The brittle clumps in the sample above show that a seal of salt did not form in this sample because the concentration of salt was too low. <\/div>\n
NASA\/Alexander Pavlov<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/figure>\n<\/div>\n
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This image is of another sample of mock Martian \u201csoil\u201d after it was removed from the Mars simulation chamber. The surface is sealed with a solid crust of salt. Alexander Pavlov and his team found that a seal formed after a sample spent three to 13 days under Mars-like conditions, and only if it had 5% to 10% perchlorate salt concentration. The color is lighter in the center where the sample was scratched with a metal pick. The light color indicates a drier soil underneath the top layer, which absorbed moisture from the air as soon as the sample was removed from the simulation chamber, turning brown.<\/div>\n
NASA\/Alexander Pavlov<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/figure>\n<\/div>\n<\/div>\n
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