Methane seasonal cycle on Mars confirmed (LIFE!)

[link]

Not how this amazing discovery is buried half way through this article.

Serpentine contains fossils. When hot water meets serpentine, methane can be produced. But that methane is biogenic, because it originates from fossils in serpentine. So, the methane on Mars was produced by life, past or present.

Regarding reply 1, according to the NASA scientist who wrote the article about methane, serpentinization is the mechanism for geologic formation of methane on Mars.

If it were geologic then it would not have a pattern. Its biology

Organics found at Mojave and Confidence Hill probably came from kerogen. Only life can produce kerogen.

Curiosity rover possibly detected past life at Mojave and Confidence Hills on Mars:
[link]

yes..
http://redplanet.asu.edu/?p=29292

""Data will hopefully be released later this year about the isotopes of methane, which can tell us how much might be produced by microbes," Dr Chopra said."
(quoted from http://www.abc.net.au/news/science/2018-07-26/mars-life-evidence-organic-carbon-methane-liquid-water/10038324
Can Curiosity rover do that?

Yes, the APXS instrument on Curiosity can, in principle at least, measure the ratios of different carbon isotopes in methane. On Earth, life has a preference for Carbon 12 over Carbon 13 (both of which are stable).

The difficulty is getting enough methane to make an accurate measurement (or over time adding together enough separate measurements to cancel out the "noise"). If we got a few more "spikes" at 10 times the background level, it might help.

I bet they already have enough data to have a rough idea, but they likely won't say anything until there is incontrovertible evidence.

Regarding reply 8, if APXS can do that, all the three rovers on Mars should have done many measurements of carbon 12 and carbon 13, because there are numerous carbon atoms on Mars surfaces. The carbon atoms may be found on brushed rocks, in drill tailings, in scooped samples, etc.

Regarding reply 9, on Earth there are numerous meteorites and 100 Martian meteorites. Many scientists have tested the meteorites' ratios of carbon 12 and carbon 13. One scientist even published an article claiming there is past life in a meteorite, based on the ratios of carbon 12 and carbon 13 found in the meteorite. However, scientists do not have a consensus that the method can prove the existence of past life on Mars or in meteorites.

Regarding Reply 8: The APXS instruments on Spirit and Opportunity (the MER rovers) are more primitive than the ones on Curiosity. They can only measure overall element abundance, not the isotopes. Even then, they can only determine abundance for heavier elements like sulfur and iron, but not lighter elements like carbon.

Come to think of it, the isotope measurements on methane would not come from the APXS anyway, which is used to analyze solid samples. I think the Tunable Laser Spectrometer (TLS) would be used to analyze gasses such as methane.