Okay, first, we don't know if there is life on Mars or not. May seem we have lots of data about Mars but most of it is from orbit - and the rovers have covered only a small part of it - and - none of the rovers have had the capabilities to spot life on Mars in the concentrations we expect them.
We know roughly what to expect if the life is anything like Earth life from the Atacama deserts and the McMurdo dry valleys - and if it's like that - then none of our roves so far would have detected life in those places on Earth. Viking theoretically could have, in the 1970s, but the one experiment on Viking with this capability had issues, it was confused by the unusual chemistry of Mars soil, not expected, no fault of the experimenter - and as a result their results are still controversial, most think they didn't spot life, some think they did.
Exomars, due to go to Mars in 2018 will be the first rover we've sent to Mars with the capability of detecting the life in the heart of the Atacama desert.
So the direct search for present day life hasn't even begun yet.
What does seem clear is that there is water on Mars at least episodically. That was proved by Phoenix through isotope measurements. It showed that there must be something on the surface that exchanges oxygen atoms with the CO2 in the atmosphere. The only really likely candidate there is water. So either widespread thin layers of water - or else episodic outgushing of water every few hundred thousand or million years or some such - or both.
And where there is water - then there's a good chance of life - though not certain on Mars, there are many other conditions especially - availability of nitrogen - and also - water activity - because of the near vacuum is hard for water to stay on the surface long enough to be useful - but not impossible if the water is salty.
There are many habitats to investigate also
That's why, to exobiologists, our search for life on Mars has only just begun. And with the challenging and varied terrain on Mars we may need to look for quite a while to find life. E.g. if there is life in the warm seasonal flows - that's hard to get to anyway -and then - might well be that only some of the warm seasonal flows are inhabited - some of the areas and only some of the strips maybe within the areas - because - unlike Earth where everywhere habitable gets colonized within weeks - it may take centuries, millennia, even millions of years on Mars - or it might happen quickly of course - but nobody knows and you can't predict.
And of course you can't see them from orbit.
Imagine looking at this from orbit, or even studying it with Curiosity
ESA’s test rover begins exploring Atacama Desert
You wouldn't spot any life there. But there is life in the Atacama desert it is just cryptic, most of it hidden beneath the surface of the soil or inside the rocks. It looks pretty much like Mars doesn't it...
Then - the whole future history of Mars may depend on what we do now.
Here is a montage I did of possible future outcomes for Mars - just as it could be Red, Green, or Blue as in that famous trilogy, it could also be black, white or purple or many other colours in case of terraforming gone wrong - or different decisions about how you deal with the planet
Maybe in the future we'll know which of these versions of Mars we want - and which is achievable also - and also know how to target the one we want and avoid the ones we don't want.
But we don't know how to do that now. And decisions made now could impact on Mars for all future time, if we introduce species to the planet that force it in one or other of these directions against our wishes - not just what species we introduce - but what they evolve into as they spread across Mars and respond to the Mars climate and the Mars climate responds to the life in various cycles, almost certainly with a strong element of chaos in the interactions as well so some parts of the process may be essentially unpredictable also.
We have no way of knowing which of these versions of Mars - or many other possibilities - is the one our descendants will want.
We might think they want green or blue Mars but they might by then long for pristine Mars - have plenty of living space for themselves in space colonies - or indeed may have solved the problems on Earth and stabilized our population (we have already reached peak child so our population may well level off) - they may not need new places to live by a thousand years from now which is when the terraforming plans would reach fruition according to the Mars society plans - so the most optimistic projections..
Or they might want the blue Mars but be unable to achieve it because of life forms we've introduced that interfere e.g. aerobes eating up oxygen as it is formed, methanogens turning it into a methane rich atmosphere - or just microscopic grazing creatures that eat all the algae they use to attempt to bring oxygen into the atmosphere.
Even if we knew what they want - we have no way of knowing how to get to whichever one we think is the best outcome. No way of predicting what way life would go and to stop the other alternatives from happening if things go wrong on a planet wide scale on Mars.
Or people just give up on the project after say 100 or 300 years or whatever, far too soon to terraform Mars. Indeed humans often give up on projects after 30 years never mind keeping at a high technology project for 1000 years.
Mars is like a giant petri dish and we have no idea what would happen to it if we introduce life to it, not had any experience of seeding a planet with life. Perhaps we might learn more from study of exoplanets. Maybe we'll even make contact with ETs who have experience of this and knows what can happen and what can go wrong with it.
But right now we have almost nothing to use as a guideline. Even the Earth's climate we hardly understand, just a few decades of good data and still endless debate about what exactly the effect will be of the 0.01% CO2 we've added to the atmosphere. And Mars is too precious to use as a petri dish and make irreversible mistakes with. Well that's what I think anyway. What do you think?
This needs to be open to public debate at any rate before anyone thinks about doing something like this with irreversible effect on Mars and future generations.
Imagined Colours Of Future Mars - White, Red, Purple, Green, Blue, Black, Or None Of The Above - Giant Petri Dish
We know roughly what to expect if the life is anything like Earth life from the Atacama deserts and the McMurdo dry valleys - and if it's like that - then none of our roves so far would have detected life in those places on Earth. Viking theoretically could have, in the 1970s, but the one experiment on Viking with this capability had issues, it was confused by the unusual chemistry of Mars soil, not expected, no fault of the experimenter - and as a result their results are still controversial, most think they didn't spot life, some think they did.
Exomars, due to go to Mars in 2018 will be the first rover we've sent to Mars with the capability of detecting the life in the heart of the Atacama desert.
So the direct search for present day life hasn't even begun yet.
What does seem clear is that there is water on Mars at least episodically. That was proved by Phoenix through isotope measurements. It showed that there must be something on the surface that exchanges oxygen atoms with the CO2 in the atmosphere. The only really likely candidate there is water. So either widespread thin layers of water - or else episodic outgushing of water every few hundred thousand or million years or some such - or both.
And where there is water - then there's a good chance of life - though not certain on Mars, there are many other conditions especially - availability of nitrogen - and also - water activity - because of the near vacuum is hard for water to stay on the surface long enough to be useful - but not impossible if the water is salty.
There are many habitats to investigate also
- Warm seasonal flows
Top candidate for search for present day life right now - these form only when temperature is above 0C, and are not linked to winds or dust storms, far too warm to be dry ice phenomena,, and are seasonal on sun facing slopes
Sadly though - on steep rather inaccessible slopes, not easy for an early mission to get to. There's a major issue also sterilizing a modern spacecraft adequately to investigate habitats on Mars for present day life. - Martian Geysers. These are thought to be dry ice phenomena. But they form because the dry ice is heated up by a "solid state greenhouse" effect. The same effect may well melt normal water ice, does here on the Earth. Similar effect could also create habitable thin films beneath the polar ice on top of the soil or rockPhoto in the News: Martian Geysers Spew Ice, Dust
- Deliquescing salts - these were first spotted as drops of what look like liquid on the Phoenix lander's legsThey grew, coalesced, dropped off, and after dropping of the leg didn't form again. Most commonly accepted, though not 100% proved explanation is that this is liquid water forming as drops of liquid around salts splashed up onto its legs during landing - the Phoenix craft landed in the bed of an ancient ocean - and much of the surface of Mars does have salt deposits like this - which can deliquesce in the 100% humidity you get in the Mars atmosphere at night - and so depending on the mixture of salts - so the water activity and temperature at which it's liquid - can be a habitat for life
- The DLR lichen and cyanobacteria experiments
These experiments showed that some arctic and alpine lichens and cyanobacteria can metabolize and photosynthesize on a simulated Mars surface, exposed directly to the sunlight in partial shade, taking in water from the atmosphere, with no supply of water at all. On going experiments but so far suggestive that life may be possible almost anywhere on Mars - though may depend on nitrogen source - doesn't need water if this is the case.
That's why, to exobiologists, our search for life on Mars has only just begun. And with the challenging and varied terrain on Mars we may need to look for quite a while to find life. E.g. if there is life in the warm seasonal flows - that's hard to get to anyway -and then - might well be that only some of the warm seasonal flows are inhabited - some of the areas and only some of the strips maybe within the areas - because - unlike Earth where everywhere habitable gets colonized within weeks - it may take centuries, millennia, even millions of years on Mars - or it might happen quickly of course - but nobody knows and you can't predict.
And of course you can't see them from orbit.
Imagine looking at this from orbit, or even studying it with Curiosity
You wouldn't spot any life there. But there is life in the Atacama desert it is just cryptic, most of it hidden beneath the surface of the soil or inside the rocks. It looks pretty much like Mars doesn't it...
Then - the whole future history of Mars may depend on what we do now.
Here is a montage I did of possible future outcomes for Mars - just as it could be Red, Green, or Blue as in that famous trilogy, it could also be black, white or purple or many other colours in case of terraforming gone wrong - or different decisions about how you deal with the planet
Maybe in the future we'll know which of these versions of Mars we want - and which is achievable also - and also know how to target the one we want and avoid the ones we don't want.
But we don't know how to do that now. And decisions made now could impact on Mars for all future time, if we introduce species to the planet that force it in one or other of these directions against our wishes - not just what species we introduce - but what they evolve into as they spread across Mars and respond to the Mars climate and the Mars climate responds to the life in various cycles, almost certainly with a strong element of chaos in the interactions as well so some parts of the process may be essentially unpredictable also.
We have no way of knowing which of these versions of Mars - or many other possibilities - is the one our descendants will want.
We might think they want green or blue Mars but they might by then long for pristine Mars - have plenty of living space for themselves in space colonies - or indeed may have solved the problems on Earth and stabilized our population (we have already reached peak child so our population may well level off) - they may not need new places to live by a thousand years from now which is when the terraforming plans would reach fruition according to the Mars society plans - so the most optimistic projections..
Or they might want the blue Mars but be unable to achieve it because of life forms we've introduced that interfere e.g. aerobes eating up oxygen as it is formed, methanogens turning it into a methane rich atmosphere - or just microscopic grazing creatures that eat all the algae they use to attempt to bring oxygen into the atmosphere.
Even if we knew what they want - we have no way of knowing how to get to whichever one we think is the best outcome. No way of predicting what way life would go and to stop the other alternatives from happening if things go wrong on a planet wide scale on Mars.
Or people just give up on the project after say 100 or 300 years or whatever, far too soon to terraform Mars. Indeed humans often give up on projects after 30 years never mind keeping at a high technology project for 1000 years.
Mars is like a giant petri dish and we have no idea what would happen to it if we introduce life to it, not had any experience of seeding a planet with life. Perhaps we might learn more from study of exoplanets. Maybe we'll even make contact with ETs who have experience of this and knows what can happen and what can go wrong with it.
But right now we have almost nothing to use as a guideline. Even the Earth's climate we hardly understand, just a few decades of good data and still endless debate about what exactly the effect will be of the 0.01% CO2 we've added to the atmosphere. And Mars is too precious to use as a petri dish and make irreversible mistakes with. Well that's what I think anyway. What do you think?
This needs to be open to public debate at any rate before anyone thinks about doing something like this with irreversible effect on Mars and future generations.
Imagined Colours Of Future Mars - White, Red, Purple, Green, Blue, Black, Or None Of The Above - Giant Petri Dish
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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