https://phys.org/news/2020-12-planet-lot-methane-atmosphere-life.html If a planet has a lot of methane in its atmosphere, life is the most likely cause: The ultra-powerful James Webb Space Telescope will launch soon. Once it's deployed and in position at the Earth-Sun Lagrange Point 2, it'll begin work. One of its jobs is to examine the atmospheres of exoplanets and look for biosignatures. It should be simple, right? Just scan the atmosphere until you find oxygen, then close your laptop and head to the pub: Fanfare, confetti, Nobel prize. Of course, Universe Today readers know it's more complicated than that. Much more complicated. In fact, the presence of oxygen is not necessarily reliable. It's methane that can send a stronger signal indicating the presence of life. Oxygen might seem like the obvious thing to look for in a planet's atmosphere when searching for signs of life, but that's not the case. Its presence or lack thereof is not a reliable indicator. Earth's history makes that clear. Modern Earth's atmosphere contains about 21% oxygen, and we know that most of it comes from organisms in the planet's oceans. But there's a hitch: Once cyanobacteria on ancient Earth started producing oxygen as a byproduct of photosynthesis, it still took an awfully long time before the atmosphere became oxygenated, possibly a billion years. What if we examined an exoplanet, found no oxygen, then moved on, not realizing that there was life down there, at the beginning of oxygenating that world? What if we were a billion years too early, and life hasn't oxygenated the exoplanet's atmosphere yet? Rocky planets have many oxygen sinks, and biologically produced oxygen wouldn't be found free in the atmosphere until those sinks were becoming saturated. more at link: the paper: https://iopscience.iop.org/article/10.3847/PSJ/abb99e Abundant Atmospheric Methane from Volcanism on Terrestrial Planets Is Unlikely and Strengthens the Case for Methane as a Biosignature: Abstract: The disequilibrium combination of abundant methane and carbon dioxide has been proposed as a promising exoplanet biosignature that is readily detectable with upcoming telescopes such as the James Webb Space Telescope. However, few studies have explored the possibility of nonbiological CH4 and CO2 and related contextual clues. Here we investigate whether magmatic volcanic outgassing on terrestrial planets can produce atmospheric CH4 and CO2 with a thermodynamic model. Our model suggests that volcanoes are unlikely to produce CH4 fluxes comparable to biological fluxes. Improbable cases where volcanoes produce biological amounts of CH4 also produce ample carbon monoxide. We show, using a photochemical model, that high abiotic CH4 abundances produced by volcanoes would be accompanied by high CO abundances, which could be a detectable false-positive diagnostic. Overall, when considering known mechanisms for generating abiotic CH4 on terrestrial planets, we conclude that observations of atmospheric CH4 with CO2 are difficult to explain without the presence of biology when the CH4 abundance implies a surface flux comparable to modern Earth's biological CH4 flux. A small or negligible CO abundance strengthens the CH4+CO2 biosignature because life readily consumes atmospheric CO, while reducing volcanic gases likely cause CO to build up in a planet's atmosphere. Furthermore, the difficulty of volcanically generated CH4-rich atmospheres suitable for an origin of life may favor alternatives such as impact-induced reducing atmospheres.
Would you say that the release of methane from the ARctic permafrost is one of the major causes of the warming in the north? Please Register or Log in to view the hidden image!
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Please Register or Log in to view the hidden image! your posting about methane based life forms on other planets and the new telescope to look for signs of that and so you are asking if arctic climate change is mostly due to methane emissions ? you seem confused about what subjects your posting about and what subjects your asking questions about. is this free thoughts about climate change & methane alternate theorys of how methane works in the atmosphere ? or alternate theorys about how global atmospheric distribution of greenhouse gases work ? or alternate theorys about global warming ? or about arctic warming theorys ? or methane sinks(in permafrost & how they work) or methane atmospheric distribution from large scale permafrost sink releases or are you asking if methane based life forms are more likely to live in the arctic ? i doubt we will be wiped out by a methane based life form zombie plague(but it is not theoretically impossible). "when arctic methane zombies attack" ... [[[ this is a different subject & i suggest your question be placed into a better context and its own thread subject]]] Permafrost methane sink release is a VERY specialised subject you would need to do a lot of back reading before any information made sense to you
Methane distribution https://en.wikipedia.org/wiki/Atmospheric_methane Please Register or Log in to view the hidden image!
EXCELLENT!!!!!!!!!!!!!!! These two graphs do answer my question. If it was true that methane was being released from the permafrost in the Arctic at levels never seen before then these graphs would have shown much higher concentrations up north. Thank you!
My primary concern related to methane being released from the permafrost in the Arctic has to do with a message from a brilliant writer several years ago:
