Water On Mars May Have Flowed For a Billion Years Longer Than Thought

Observations by a long-running Mars mission suggest that liquid water may have flowed on the Red Planet as little as 2 billion years ago, much later than scientists once thought. Space.com reports: Scientists charted the presence of chloride salt deposits left behind by flowing water using years of data from NASA's Mars Reconnaissance Orbiter (MRO), which has been orbiting the Red Planet since 2006. By studying dozens of images of salt deposits taken by the spacecraft's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), the scientists interpreted a younger age for the salt deposits using a method "crater counting." The younger a region is, the fewer craters it should have, with adjustments for aspects such as a planet's atmosphere, allowing scientists to estimate its age. The new results push forward the existence of water on Mars from 3 billion years ago to as little as 2 billion years ago, based on the observations, which could have implications for life on Mars and more broadly, the planet's geological history. [...]

The scientists also created elevation maps using MRO's wide-angle context camera, and the zoomed-in views provided by the High-Resolution Imaging Science Experiment (HiRISE) that can spot craters as small as the Curiosity or Perseverance Mars rovers. The salt minerals were first spotted by a different spacecraft 14 years ago, called Mars Odyssey, but MRO's advantage is it has higher resolution instruments than its older (and still operational) companion in orbit. The study based on the research was published in AGU American Geophysical Union Advances.

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[Anonymous Coward]

um read the bible

Implications for Life?

[Roger W Moore]

I don't understand why they think that this is likely to have large implications for life on Mars. The oldest evidence of life on Earth is 3.5 billion years old but it was not until 500 million years ago that multi-cellular life evolved. Assuming that is somewhat typical (which we admittedly have no clue about) all this would mean is another billion years of single-celled life floating around whatever water there was on Mars.

Re:Implications for Life?

[nightflameauto]

Without further study I don't think anybody can make the assumption that an extra billion years of liquid water on Mars means a better overall chance at life developing on the planet. All that really happened is that we extended the amount of time the planet had to develop or foster life within liquid water by that billion years. Until we actually detect some evidence that life existed on the planet at some point, and who knows if that will ever happen, we just discovered there was a longer period of time for those random rolls of the dice to turn up in a favorable result.

It's interesting to me from the perspective of what it means for the planet's overall geological history. I think they just toss the whole life thing in there to try and drum up more excitement.

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[Roger W Moore]

My point was that, at least on Earth, single-celled life evolved incredibly quickly once water was available but then took 3 billion years to figure out how to go multi-cellular. If this is typical, then regardless of whether the water disappeared 2 or 3 billion years ago on Mars life would only have ever got to the single-cell stage of evolution which is hardly much of a difference. It's the discovery of any life on Mars that will be huge, not whether it lasted for 0.5 or 1.5 billion years.

Longer for live to evolve in the first place

[Viol8]

Even finding evidence of single cell life would be a big deal and I imagine thats all most scientists are expecting if evidence for life turns up.

Personally I don't think it will because IMO (based on nothing but gut feeling) is that the jump from a chemical soup to what we'd recognise as a self replicating precursor to life is extremely rare and probably requires just-so conditions one of which is no liquid water but I suspect thats not nearly enough.

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[Viol8]

That should read "no doubt liquid water".

Re:Longer for live to evolve in the first place

[LeDopore]

Life started on Earth very soon after there was liquid water, yet it took billions of years before eukaryotes arose. Being a eukaryote is a big deal: having mitochondria lest us have huge genomes compared to a bacterium's, and that opens the door for complexity and sophistication. Every living creature with interesting structure is a eukaryote, and the innovation that let us attain this complexity (a successful endosymbiosis) happened exactly once in the whole history of life on Earth.

Imagine trying to eat rabbits but getting indigestion, and having the rabbits start breeding inside of you but lose almost all their rabbit-like traits, and in the process you gain superpowers of being able to metabolize grass and grow a hyper-brain that lets you out-compete every other sapient being on the planet. That's not much more wild a story as what actually happened with the first successful endosymbiosis.

The ratio of (time-to-first-life given temperate water on Earth) / (time-to-eukaryotes given first life on Earth) is tiny; maybe 1:100 or so. That's evidence that complex life might be much more rare than simple life. In fact, I would guess that successful endosymbiosis might be one of the strongest of the great filters; it might be that complex life is nearly vanishingly rare and it's only the anthropic principle that gives us a reason for finding it on Earth.

If that's true then we'd anticipate finding simple life on other rocks, but rarely anything morphologically complex. Increasing the length of time Mars had water probably increases the chances they got bacteria-like life, but I would be surprised if Martian life ever had anything like membrane-bound organelles.

Re: Longer for live to evolve in the first place

[Viol8]

We still dont if the evolution of even simple life is chemically inevitable given enough time and the right conditions , or whether it was a cosmic fluke - perhaps a cosmic ray hit something at just the right spot at the right time never to be repeated. We may never know.

Any sort of life is a very big deal

[aberglas]

Exactly as above.

We know that it is pretty likely that once some sort of prokaryote life exists, then given enough time it is fairly likely that more complex forms will arise.

But we have absolutely no idea about the likelihood of prokaryotes forming spontaneously.

The Miller-Urey experiments tried simulating the early earth in just the right way to produce something interesting, and some interesting chemicals were created, but nothing even close to life.

Prokaryote life might be common in the right planetary

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[LeDopore]

Prokaryote life might be common in the right planetary conditions. Or it might only happen once in a galaxy. Or indeed the entire universe.

If prokaryotic life were super unlikely to arise, then you would expect (given that it did arise at all) it would have happened at a random time picked from a uniform probability distribution between now and when the Earth started. What we see is prokaryotic life emerging by when temperate Earth was about 1% as old as it is now. it would be a big coincidence that prokaryotic life arose pretty much right after Earth was cool enough to have water.

Coincidences do happen occasionally, and the fact that prokar

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[Roger W Moore]

But we have absolutely no idea about the likelihood of prokaryotes forming spontaneously.

Agreed, but we learn something about that likelihood by determining whether or not life evolved on Mars, regardless of how long water was around so there is not much of an implication there.

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[nospam007]

"Assuming that is somewhat typical (which we admittedly have no clue about) all this would mean is another billion years of single-celled life floating around whatever water there was on Mars."

They hope for some Barsoomians.

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[quantaman]

I don't understand why they think that this is likely to have large implications for life on Mars. The oldest evidence of life on Earth is 3.5 billion years old but it was not until 500 million years ago that multi-cellular life evolved. Assuming that is somewhat typical (which we admittedly have no clue about) all this would mean is another billion years of single-celled life floating around whatever water there was on Mars.

Well single-celled life is still life.

Either way, the longer the planet had water the more opportunity for life to evolve, an extra billion years seems significant.

Personally, when it comes to single vs multicellular life I'm curious what role the immune systems have to play. I always find it kinda weird that multicellular organisms don't get wiped out by single celled pathogens that can evolve at rates several orders of magnitude faster than them.

I assume our immune systems have some special tricks (only p

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[RockDoctor]

I assume our immune systems have some special tricks (only possible for multicellular organisms)

Ignoring the trivial aspect of having differentiated cells for different functions in the immune system, are you also claiming that prokaryotes (and early eukaryotes) do not have batteries of biochemical "dirty tricks" for influencing (mostly badly) the biochemistry of other single-cell organisms they encounter?

There is a well-developed field of study in how "biofilms" regulate their composition (including multi

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[quantaman]

I assume our immune systems have some special tricks (only possible for multicellular organisms)

Ignoring the trivial aspect of having differentiated cells for different functions in the immune system,

For sure, but pathogens can still evolve way faster than we can.

are you also claiming that prokaryotes (and early eukaryotes) do not have batteries of biochemical "dirty tricks" for influencing (mostly badly) the biochemistry of other single-cell organisms they encounter?

Well no, but though numbers (and lifespan) they're a lot more capable of dealing with the evolutionary speed of things they encounter.

There is a well-developed field of study in how "biofilms" regulate their composition (including multiple different species of distantly-related organisms) and work to repel "borders". It is a field of considerable medical importance (think, for example, of the biofilms coating your teeth and gut), for one thing. It's also of more theoretical interest as to how cells several billion years ago started to develop the (chemical) machinery of interaction, communication and competition, which includes the origins of multicellularity (in a single genetic lineage, contra multicellularity in a multi-species biofilm) and the origins of immunology.

I'm not trying to push any weird pseudo-science agenda. I just genuinely find it counter-intuitive that trees can live thousands of years without waves of funguses (or beetles) evolving around all of its countermeasures and wiping them all out. I suppose biofilms are also part of the answer but complex multicellu

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[RockDoctor]

If this is a field you're more familiar would you expect unicellular life to regularly progress to complex life given enough time (and environment), or do you think complex life would often struggle with ways not to be eventually devoured by rapidly evolving microorganisms?

Well, not in a professional sense - I hit rocks for a living. But I've been fascinated by OoL (Origin(s) of Life) since before I went to university.

Would I expect ... well, we know it has happened at least once. Whether we'd expect it? W

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[HeadSoft]

A billion years of single-celled life would be a pretty big deal.

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[RockDoctor]

I don't understand why they think that this is [...]

Which "they"? The scientists, or the people writing clickbait articles for space.com (which I didn't bother to read ; I haven't read the AGU article either, but I'd read that in preference to something from space.com, because I'd still need to read the AGU article to figure out what had been distorted by the space.com writers)?

The oldest evidence of life on Earth is 3.5 billion years old

Wellll ... there is that claim of a "life-like" C-13 content in carbon

We need eyeballs on this ASAP

[AndyKron]

We need to get a rover or something up there and have a look. Maybe a drone, too.

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[jfdavis668]

Mars is the best place for the reds.

engineering change notice

[cellocgw]

excellent - now my Time&Space Machine needs a much smaller delta-time range and I can go canoing along the canals of Mars.

Ray was right

[Walt Dismal]

So Ray Bradbury was right, just 2 billion years too late. Talk about nostalgia, he won the cake.