Just because we found methane on Mars doesn’t mean there are cattle farms on the red planet.
Hey guys, Amy here for DNews.
In the ongoing and imagination-capturing search for life on other planets, methane is one
of the gases that gets people really excited.
Methane is an extremely simple molecule made of one carbon atom surrounded by four hydrogen
atoms.
It’s one of the greenhouse gases that exists in trace amounts in our atmosphere, and it’s
created in oxygen-free processes in biological organisms.
A couple of examples: Archaebacteria release the greenhouse gas in rice fields, and most
famously (or infamously, perhaps) cows release methane through flatulence…
they fart it out.
Biological production of methane accounts for most of the gas’ existence on our planet,
so it stands to reason that finding methane on Mars would imply that there’s some organism
producing it on that planet as well.
Except that there are other ways to produce methane without biological processes.
Methane can come from rocks.
It’s possible for ancient methane to be released from water-formed inclusions and
cavities in basalt, a type of rock that is extremely common on Mars.
Basalt can incorporate methane through both biological and geological processes, like
the process that turns olivine into serpentinites, a type of rock composed of serpentine minerals.
That methane can be released when the rock is broken apart, like when it’s drilled
into, and found using spectroscopy.
And we’ve actually found traces of Methane on Mars before, granted, a few of those times
it was in air delivered to Mars trapped in an instrument, so we were actually detecting
Earth methane.
The methane we’ve detected on Mars in the past has been fairly widely distributed over
the planet in patches that vary over time suggesting that the gas is released from subsurface
stores and is destroyed pretty quickly.
On Mars where the atmosphere is thin, heavily composed of carbon dioxide, and where there’s
no magnetic field to protect the gases in the atmosphere, methane lasts only months
compared to the 300-plus year lifetime it has on Earth.
The other part of the puzzle is the low amount of methane on Mars compared to Earth; the
recent spike Curiosity found peaked at 7 parts per billion.
On Earth, we’ve got about 1,600 parts per billion of methane.
It’s very possible that the production and level of methane on Mars is so low to be negligible
on Earth but are exciting on Mars because it’s all we have.
It could be something awesome, but it could also be nothing.
Are you guys on team something exciting to come from methane on Mars?
Let us know in the comments below or you can catch me on Twitter as @astVintageSpace.
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