In what was two of the greatest leaps yet in the search for life on Mars, today that
planet has once again tantalized us with what might be signs of both past and present life.
The first came from a 3.5 billion year old layer of rocks that the Mars Curiosity rover
drilled into.
Reported in a paper by Jennifer Eigenbrode and colleagues, link below, within this rock
layer, they detected organic molecules.
Mars has been hinting that something odd is going on on its surface for a while.
During the Viking missions, for example, two separate experiments on each lander designed
to search for life returned positives.
Those results were called into question, and remain so to this day, partly because another
experiment showed no evidence of organics on Mars.
Without organics, carbon-based life as we know it cannot get started.
But, that equation changed when scientists found perchlorates in the Martian soil.
We’ve heard a lot about perchlorates lately in relation to humans colonizing Mars.
Perchlorates are bad specifically because they destroy organic molecules.
The implication here is that while the surface of Mars may not have much in the way of organics
now, though at least some have been detected, it may have had plenty 3.5 billion years ago
when Mars was a very different and habitable environment.
In addition to organic molecules, the researchers also found molecules that are probably parts
of what once were much larger organic molecules.
But, perhaps most interestingly in this, are the concentrations of organics in the rock.
They look similar to earth rocks of the same age, and on earth, that is directly related
to the presence of life.
In other words, it’s possible, though not provable that life was responsible for the
organics detected in the layer of rock on Mars.
The second discovery is perhaps even more tantalizing.
We’ve known for a while that Mars has methane emissions.
Methane can be produced two ways, geological and biologically.
On earth, most of our methane is biological.
On Mars, we don’t know what produces it.
In a paper by Christopher Webster and colleagues, they detail that Mars’ methane appears to
seep from underground reservoirs, which would be what you would expect if the methane were
being created by a geologic process.
But there’s more, the researchers found that the concentrations of methane in the
Martian atmosphere cycles seasonally with the highest levels in the middle of summer
in the Northern Hemisphere.
This essentially means that Mars is producing its own methane, rather than being delivered
to it by material falling on the planet.
Methane itself is a gas created by life, and seasonal behaviour certainly raises an eyebrow,
but it could also be that the methane is geologic in nature, gets trapped on its way up, and
the warm weather allows more methane to free from the ground.
We now have multiple indicators that something strange is going on with Mars.
These new findings add to that list, but there are more.
In addition we have what may be microfossils of bacteria present in some of the Mars meteorites,
though that is still being debated.
We also have what look suspiciously like bacterial mats preserved in rock on Mars and unexplained
short term rises in methane measured by Curiosity.
None of these are settled, but the chances of Mars having or having had life seem to
do nothing but rise.
The discovery of life on Mars should that ever happen will have profound consequences.
Some will say meh, it’s just a microbe, but hiding in that is a huge wildcard.
If we find that the Mars life is unique, it is not genetically related to us, then we
can say for the first time out of a science fiction context “We have discovered an alien
lifeform”.
But if it’s shown to be related, that opens up a huge question.
It would mean that panspermia did indeed occur.
So on which of the two planets, Mars and Earth, did life originally arise?
It would then be entirely possible that we are not technically native to planet earth,
but rather our planet of origin is Mars.
Thanks for listening!
I am science fiction author and futurist John Michael Godier currently excited about reconquering
the ancestral homeworld and punishing the inhabitants for our 3.5 billion year exile!
It’ll be like “where’s JMG”, “I dunno, last I saw he was lysoling a rock”
and be sure to check out my books at your favorite online book retailer and subscribe
to my channel for regular, in-depth explorations into the interesting, weird and unknown aspects
of this amazing universe in which we live.