An interdisciplinary research group from Aarhus University has proposed a previously overlooked physical-chemical process that can explain the rapid disappearance of methane from Mars' atmosphere
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.
This is a 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.
Credit: Mars Simulation Laboratory, Aarhus University
For approx. 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
Aarhus researchers have just published an article in the journal Icarus in which they propose a new mechanism that can explain the removal of methane on Mars. For years, the multidisciplinary Mars group 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.
Professor Kai Finster | EurekAlert!
Modelling leads to the optimum size for platinum fuel cell catalysts: Activity of fuel cell catalysts doubled
03.07.2019 | Technische Universität München
OU study expands understanding of bacterial communities for wastewater treatment system
14.05.2019 | University of Oklahoma
An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".
The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...
An interdisciplinary research team at the Technical University of Munich (TUM) has built platinum nanoparticles for catalysis in fuel cells: The new size-optimized catalysts are twice as good as the best process commercially available today.
Fuel cells may well replace batteries as the power source for electric cars. They consume hydrogen, a gas which could be produced for example using surplus...
The fly agaric with its red hat is perhaps the most evocative of the diverse and variously colored mushroom species. Hitherto, the purpose of these colors was...
Physicists at the Max Planck Institute for Nuclear Physics in Heidelberg report the first result of the new Alphatrap experiment. They measured the bound-electron g-factor of highly charged (boron-like) argon ions with unprecedented precision of 9 digits. In comparison with a new highly accurate quantum electrodynamic calculation they found an excellent agreement on a level of 7 digits. This paves the way for sensitive tests of QED in strong fields like precision measurements of the fine structure constant α as well as the detection of possible signatures of new physics. [Physical Review Letters, 27 June 2019]
Quantum electrodynamics (QED) describes the interaction of charged particles with electromagnetic fields and is the most precisely tested physical theory. It...
For the first time ever, experimental physicists have been able to influence the magnetic moment of materials in sync with their electronic properties. The coupled optical and magnetic excitation within one femtosecond corresponds to an acceleration by a factor of 200 and is the fastest magnetic phenomenon that has ever been observed.
Electronic properties of materials can be directly influenced via light absorption in under a femtosecond (10-15 seconds), which is regarded as the limit of...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
08.07.2019 | Interdisciplinary Research
08.07.2019 | Earth Sciences
08.07.2019 | Information Technology