Comment by jonmc12 | Hacker News Reader

Comment by jonmc12 | Hacker News Reader

Methanogens have been discovered in 3.5B yr old rock on earth [1]. Organisms capable of producing methane have been identified only from the domain Archaea.

Other methane discoveries in solar system [2]:

  - 2004, methane was discovered in the Martian atmosphere by M.J. Mumma of NASA's Goddard Flight Center
  - 2004, martian atmosphere finding verified by the Mars Express Orbiter
  - 2005, Titan's atmosphere by the Huygens probe
  - 2015, the Cassini orbiter spacecraft on discovered the Enceladus (Saturn's moon) plume which has all the ingredients for methanogenesis-based life forms to feed from.  Suggested hot water is interacting with rock beneath the sea.
  - 2017, new findings of Enceladus plume support that conclusion and add that the rock appears to be reacting chemically.
  - 2018, NASA disclosed in a press conference that its Curiosity rover had documented seasonal fluctuations of atmospheric methane levels on Mars.

[1] https://www.newscientist.com/article/dn8882-methane-making-m... [2] https://en.wikipedia.org/wiki/Methanogenesis#Extra-terrestri...

But, presence of methane doesn't necessarily indicate life. I mean, doesn't Titan have oceans of liquid methane with no known indication of life?

I get that detecting previously unseen organic compounds on Mars is a big deal, but it doesn't necessarily indicate that life was once present on Mars. I think it increases the probability that it could have existed, but it falls short of a conclusive "Life once existed on Mars" claim.

We didn’t detect any previously unseen organic material on Mars.

We’ve finally detected carbon concentration simmilar to what we’ve expected to see based on mars originated meteorites found on earth and we’ve now have more evidence for a cyclic release of methane on Mars however methane isn’t rare it’s a combination of the most and the 4th most common elements in the universe.

Methane isn't rare, but it also isn't stable. Something must be producing it, somehow. That's the interesting part.

But why it is not stable on Mars? Mars is colder than Earth and have no free oxygen. Maybe underground gas leaks in atmosphere and, because atmosphere is much thinner, colder, and lacks O2, it just stays in atmosphere longer and in higher relative concentration.

Methane like all other simple and even complex organic and near organic compounds is produced through photochemistry constantly in the solar system.

Titan is full of it, Jupiter has more of it likely than all of the solar system combined, and we’ve already proven that cosmic dust and comets smell like farts.

Mars with its thin atmosphere and lack of magnetic field would be producing organic compounds constantly as high energy cosmic and solar radiation hits the surface.

If anything for Mars it seems that the source of hydrogen might be a bigger mystery but it should have enoguh water in the soil to be ionized and broken down into molecular hydrogen and oxygen allowing organic compounds to form.

The interesting part is the cyclical release during the hottest months of the year it could be biological but it could also and much much much more is just a seasonal pheonomon tied to the temperature.

> cosmic dust and comets smell like farts.

Just imagining a kid at a science fair having made that legitimate discovery but being dismissed by teachers

Methane is odorless [1].

AFAIK the smell in farts is mercaptanes (thiols, organic sulfur compounds).

[1] https://en.wikipedia.org/wiki/Methane

Yep but Sulfur compounds are not rare, ammonia, sulfuric acid many other sulfides and non sulfuric complex molecules like formaldehyde exist in space in plenty.

Would any Earthling Methanogens survive on Mars? How many of them would there be with nothing to kill them?

Hydrocarbons are also produced photochemically, Jupiter probably has more methane than anywhere else in the solar system (possibly combined but it can’t do the back of the envelope math for this one) despite it being only a small fraction of a fraction of a percent of its atmosphere.

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