[AS]Curiosity Detects Large Methane Burst on Mars, NASA Orders Follow-Up Testing

[Orionid]

Curiosity Detects Large Methane Burst on Mars, NASA Orders Follow-Up Testing
By Paul Scott Anderson, on June 22nd, 2019


Self-portrait of Curiosity in Gale Crater on Mars. Photo Credit: NASA/Agence France-Presse/Getty Images

It seems that Mars is belching methane again. NASA’s Curiosity rover has detected a new burst of the gas, it was reported today in the New York Times.

The new detection of the gas – which can come from either biology or geology – happened last Wednesday.

The news hasn’t been formally announced by NASA yet, but scientists involved did talk to the NYT about it. And now the team is going to do follow-up experiments this weekend to further analyze the results.

“Given this surprising result, we’ve reorganized the weekend to run a follow-up experiment,” Ashwin R. Vasavada, the project scientist for the mission, wrote to the science team in an email that was obtained by The Times.


Diagram depicting the seasonal variation of methane in the Martian atmosphere as detected by Curiosity. Image Credit: NASA/JPL-Caltech

The new results from the rover should be back on Earth by Monday. The subsequent testing was considered important enough that other previously scheduled science work was postponed to do the follow-up testing.

Previously, the largest spike in methane detected by Curiosity was 7 ppb (parts per billion), back in 2013. But the spike from this past week was three times larger, at 21 ppb.

Since 2013, Curiosity had also found evidence that the methane was seasonal, peaking during the summer. This latest observation would seem to fit that pattern as well.


This image illustrates possible ways methane might be added to Mars’ atmosphere (sources) and removed from the atmosphere (sinks). NASA’s Curiosity Mars rover has detected fluctuations in methane concentration in the atmosphere, implying both types of activity occur on modern Mars. Image Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan

The methane levels detected previously were not enough for the rover to be able to study the isotope of the gas, to try to determine whether it is biological or non-biological in origin. Even then, a definitive answer would not be easy with the equipment Curiosity has. Whether the scientists can do an isotope analysis this time or not is not known yet.

ESA’s Trace Gas Orbiter (TGO), part of the ExoMars mission, had found no methane when it examined the atmosphere last year, but that may simply be due to the fact that the methane cycle appears to be seasonal.

It turns out that TGO passed over Curiosity’s location in Gale crater on the same day as the methane detection. Marco Giuranna, a scientist at the National Institute for Astrophysics in Italy, and who is in charge of the methane measurements from the Mars Express orbiter, said that there have been other observations as well, both before and after the big one from Curiosity.

“A lot of data to be processed,” Dr. Giuranna said. “I’ll have some preliminary results by next week.”


Previous methane measurements by NASA’s Curiosity in Mars’ Gale Crater, showing the spike in 2013. The graph covers a span of time from August 2012 to September 2014, labeled on the horizontal axis by the number of sols, or Martian days, since the rover’s landing on Mars — sols 1 through 750. Image Credit: NASA/JPL-Caltech

Most of the methane on Earth comes from living organisms, but the origin of Mars’ methane is not know yet. It could be either biological or geological, or both. Even just a geological source would be very interesting however, since it could mean there is still active geology in Mars’ subsurface, which itself could provide heat and moisture for possible microbes.

The largest-ever confirmed plumes of methane were previously detected by telescopes on Earth, at a maximum of 45 ppb in 2003. There have been numerous detections by telescopes and Mars orbiters since then, although none of those were shown to be seasonal. From Earth telescopes, a global average value of 10 ± 3 pppb was observed in 1999. The Mars Express spacecraft measured a global average abundance of 15 ± 5 ppb from 2004 to 2010, while the Mars Global Surveyor spacecraft measured abundances ranging from 5 to 60 ppb, although the claims of local variations were later withdrawn. The background level of methane seen by Curiosity has been about 0.69 ± 0.25 ppb, in between spikes.

This new detection of methane is exciting, but we will will have to wait just a bit to hear more details. Stay tuned to AmericaSpace for more information as it becomes available.

Source: https://www.americaspace.com/2019/06/22/curiosity-detects-large-methane-burst-on-mars-nasa-orders-follow-up-testing/

[Orionid]

Methane vanishing on Mars: Aarhus researchers propose new mechanism as an explanation.
2019.07.02 | KAI FINSTER  [Aarhus University]

The processes behind the release and consumption of methane on Mars have been discussed since methane was measured for the first time for approx. 15 years ago. Now, an interdisciplinary research group from Aarhus University has proposed a previously overlooked physical-chemical process that can explain methane's consumption.


Simulation of wind erosion on Mars. The quartz ampoule contains particles of olivine basalt and a Mars-like atmosphere. By shaking the ampoule, the researchers simulate wind-generated saltation, ie. that the wind causes the sand grains to make short jumps over the surface. The friction of the particles creates electrical charges, and the yellow star illustrates that an argon atom has lost an electron. The small electrical charges cause the particles to glow slightly, as illustrated in the four pictures to the right. Graphics: Mars Simulation Laboratory, AU

About 15 years ago, one could for the first time read about methane in Mars's atmosphere. This aroused great interest, also outside the scientific circles, since methane, based on our knowledge of methane on Earth, is considered a bio-signature, i.e. signs of biological activity and thus life.

In subsequent years, one could read articles that alternately reported on methane's presence and absence. This variation led to doubts about the accuracy of the first methane measurements. Recent measurements of methane in Mars' atmosphere have now shown that its dynamics is real enough and the fact that sometimes only very low concentrations can be measured is due to an unresolved mechanism that makes methane disappear from the atmosphere and not a mis-measurement.

The methane sources or the causes for its disappearance have not been identified at present. Especially the latter, the rapid disappearance of methane, lacks a plausible mechanistic explanation. The most obvious mechanism, namely the photochemical degradation of methane caused by UV radiation, cannot explain methane's rapid disappearance, which is a prerequisite for explaining the dynamics.   

Erosion and chemistry

An multidisciplinary group of researchers at Aarhus University have just published an article in Ikarus, in which they propose a new mechanism that can explain the removal of methane on Mars. For years, the multidisciplinary Mars group (marslab.au.dk) has investigated the importance of wind-driven erosion of minerals for the formation of reactive surfaces under Mars-like conditions. For this purpose, the research group has developed equipment and methods for simulating erosion on Mars in their “earthly” laboratories.

Based on Mars-analogue minerals such as basalt and plagioclase, the researchers have shown that these solids can be oxidized and gases are ionized during the erosion processes. Thus, the ionized methane reacts with the mineral surfaces and bonds to them. The research team has shown that the carbon atom, such as methyl group from methane, directly binds to the silicon atom in plagioclase, which is also a dominant component of Mars' surface material.

What the researchers see in the laboratory could also explain the loss of methane on Mars. By this mechanism, which is much more effective than photochemical processes, methane could be removed from the atmosphere within the observed time and then deposited in the Martian source soil.

Affects the possibility of life

The research group has furthermore shown that these mineral surfaces can lead to the formation of reactive chemicals such as hydrogen peroxide and oxygen radicals, which are very toxic to living organisms, incl. bacteria.     

The group's results are important for assessing the possibility of life on or near Mars' surface. In a number of follow-up studies, the researchers will now examine what is going on with the bound methane, and whether the erosion process in addition to the gases in atmosphere also changes or even completely removes more complex organic material, which can either originate on Mars itself or has come to Mars as part of meteorites.     

The results thus have an impact on our understanding of the preservation of organic material on Mars and thus the fundamental issue of life on Mars - inter alia in connection with the interpretation of the results of the upcoming ExoMars rover, which ESA is expected to land on Mars in 2021.

Further information:

The article in Ikarus: "Light on windy nights on Mars: A study of saltation-mediated ionization of argon in a Mars-like atmosphere"

Source: http://scitech.au.dk/en/about-science-and-technology/current-affairs/news/show/artikel/methane-vanishing-on-mars-aarhus-researchers-propose-new-mechanism-as-an-explanation/