Few appreciate the extraordinary value and uniqueness of a pristine Mars. The popular idea we are all used to, from science fiction films and stories, is of astronauts in spacesuits bravely setting forth to colonize the planet. Yet some scientists are passionate about the need to keep the surface pristine for now. Let’s find out why.
Related blog posts:
Space habs could house trillions
Terraforming Mars needs great care
Surface mission to Mars, terrible idea, easily made wonderful
To understand the value of Mars and its uniqueness to science we need some background geological history. It is a fascinating story.
Near twin in its early years
It seems likely that Mars had extensive oceans during its earliest Noachian period, which lasted for a few hundred million years. Its oceans almost certainly contained many organics from comets just as for Earth. All this suggests that for several hundred million years, Mars was a near twin of Earth. With the possible exception of Venus (far less well understood than Mars), it is the only planet in our solar system that was like Earth in this respect in its early years.
Life started on Earth within 700 million years of its formation, not long after the end of the late heavy bombardment period. So the earliest years on Earth are of intense interest to scientists interested in the origin of life and the life sciences. It started so quickly on Earth that it seems almost certain it must have started on Mars too while it was still hospitable to life.
If that didn’t happen; if life never started on Mars; then it is even more interesting to find out how far it got and why it didn’t evolve life, and what happened instead to all those organics. If they didn’t form life on Mars did they form some type of proto life? Were alternative pathways explored, unsuccessfully? Might this tell us something about what happens on other planets in our Galaxy, or about the process of evolution of life itself?
Later stages on Mars
After the initial stages Mars followed a different path from Earth. It lost nearly all its atmosphere leaving an atmosphere so thin it would count as a laboratory vacuum. It cooled down so much that the average temperature at the equator is the same as Antarctica and the temperature swings are far greater than in Antarctica. Water on the surface now boils at just a few degrees centigrade even in the deepest places where the air is at its densest and no standing water can survive there for long. The water froze to ice or escaped into space leaving a dry surface though still with some possibilities for salty brine. It got so dry the surface turned to dust and regularly dust storms cover the entire surface for weeks on end
This makes it inhospitable to most modern Earth life. Yet some extremophiles could survive on Mars as it is today. There are still locations where water or salty brine could provide the conditions needed for life, sub surface, or in melted pockets of water around grains of dust embedded in snow, or in the case of some lichens, on the surface rocks using just the brief morning and evening dews.
There is no obvious evidence of Mars life on the surface so, most likely evolution on Mars didn’t get as far as those lichens. Early life on Mars (if it existed) either became extinct, or else survives but only in special niches on Mars, quite possibly deep under the polar ice or sub surface.
No Continental Drift
One major difference between Mars and Earth is that there is no continental drift. The entire surface of Mars is pretty much as it was when it first lost its atmosphere. Any early oceans just dried up in situ. Oceans that were separated from others, never joined up or were disturbed in any way.
That’s why Olympus Mons got so large. Without continental drift the hot spot that formed the volcano simply stayed in one place for billions of years and created a volcano far larger than any on Earth.
After the Noachian period, there was a period of great floods and massive rivers called the Hesperian period which created huge deposits such as Mount Sharp. The entire 5.5 km high Mount Sharp at the Curiosity landing site is believed to be a massive pile of debris left from the early floods on Mars.
And then all the action stopped, the oceans dried up, the rivers dried up and apart from the occasional impact that created craters and local flooding doubtless, Mars became what it is today and stayed the same.
Mars is a giant deep freeze preserving the first few hundred million years of a near twin to Earth
All the deposits from the early oceans, rivers and floods on Mars are still just there as they were left, waiting to be studied. The temperatures stay well below zero a short way below the surface. There are few volcanoes, none currently active. There is no continental drift to subduct the materials below the surface and metamorphize them. Only cosmic rays can disturb it, and if you dig down ten meters or so you get well beyond the reach of them. The air pressure is so low that ice sublimes easily, but apart from that, conditions are perfect to preserve organic material from those early days.
Scientists are particularly interested in clays on Mars such as nontronite, and also sulfate materials which are known to be capable of encapsulating organic materials and preserving it for extremely long periods of time. The Curiosity landing site was chosen partly because of the presence of these materials there. See for instance this transcript of an interview with Jennifer Eigenbrode about Biogeochemistry with Curiosity.
Compare Earth, with almost nothing left of the early record. Geologists investigating the earliest times on Earth have to study tiny fragments, pebbles embedded in later rocks,
We haven’t begun to study this material on Mars. No mission to Mars to date has been able to dig significantly below the surface. No instrument has been sent to Mars as powerful as a laboratory optical microscope. Curiosity was heralded as a major advance over earlier missions because it has the equivalent of a geologist’s hand lens. But this lens is not powerful enough to see micro-organisms, living or fossil.
There are expeditions on the drawing board that will take more powerful instruments to Mars, such as miniature scanning electron microscopes, and miniature DNA sequencers. Also there are planned missions to dig many meters below the surface. But it will be for some years yet before they launch.
The tremendous value of a pristine Mars for science
In this respect Mars is like Antarctica. Antarctica would be easier to colonize than Mars, or the Moon, is a safer place to live than either, and has potential mineral wealth that could be exploited to finance a group of keen colonists. You could have greenhouses there too, with artificial light in winter, and grow your own food just as on Mars.
Yet, everyone agrees that Antarctica is so valuable to science that it would be a tragedy to colonise it and make it into just one more human living area on Earth. Tourists to Antarctica are carefully supervised to make sure they take no new species to the continent, for instance by accident on their boots. The current Antarctica treaty doesn’t need to be enforced particularly strongly - you don’t get UN gun boats defending the shores of Antarctica :).
Mars is of far far more interest for science than Antarctica. Those ocean and flood deposits could have evidence of early attempts at life that followed different paths from life on Earth. Different deposits on Mars may have evidence of different pathways if isolated from each other since the planet formed.
Instead of tiny fragments in later rocks as we have on Earth, we have multiple kilometer thick deposits to examine on Mars.
There may also be evidence of the stages before life. The earliest life on Earth is already so complex that it is extremely hard to understand how it arose.
There are many competing theories of Abiogenesis (formation of life) and the precursors for life itself, such as RNA world, Zinc world, Coenzyme world, the list goes on and on. But there is no consensus, as there is no way really to distinguish between them using the geological record on Earth. See the Wikipedia article on Abiogeneisis for an idea of the vastness of this subject.
Study of life, proto life, or whatever there is on Mars in those deposits will shed light on that whole area of scientific knowledge and understanding, in ways we simply can’t begin to do on Earth.
The oceans of early Mars may have kept separate from each other because of the lack of continental drift. If so we can also explore to see if these followed different paths of evolution, or all followed exactly the same path.
Some of the things we can expect to see on Mars if life never evolved, include nanobes (just 20 nanometers in diameter) or other protobionts. At least some form of complex structures like protobionts are sure to be there since on Earth they form in simple laboratory experiments simulating conditions on early Earth.
Then it seems at least possible that on Mars there is nothing to consume the early remains or transform them. If we dig deep enough on Mars we may well find pristine preserved organic remains from those early years.
Mars is of great value for study of the origins of life even if life never evolved there.
What if Mars is already contaminated?
It is certainly possible that life from Earth has already started to thrive on Mars brought there by our spaceships, due to many mission mishaps in the past. It’s also possible that life was brought there from Earth via meteorites.
The exchange by meteorites is only possible during the larger meteorites of 10 km or larger, like the one that contributed to the extinction of the dinosaurs, and the material probably took millions of years to reach Mars, but could have happened.
Either way, it is likely that only a small number of species have reached Mars. Adding more species greatly complicates the search for the origins of life. If biologically similar it makes it hard to disentangle the history and figure out which organisms came from Mars originally, especially since introduced life is likely to evolve and radiate adaptively on Mars.
It can also out compete native Mars life. Life that evolved on Mars may not be as well adapted for Mars as Earth extremophiles, despite their billions of years of evolution. It could be a similar situation at the microorganism level to the marsupials in Australia. For some reason evolution never hit on placental animals in Australia, and well adapted animals there were out competed by placental animals from Europe.
Also, any native Mars life, or life that has made the difficult journey to Mars from Earth may only be able to survive in special niche locations on the surface. This could leave other areas unchanged since the Hesperian or Noachian periods.
Nearest planet like Mars is likely to be many light years away
Yes there are other locations in our solar system where liquid water exists to this day. These may possibly have life in some form or other to this day, for instance in the under surface oceans of Europa, one of Jupiter’s moons; or Encladus, one of Saturn’s moons. But none of them remotely resembled Earth in its early years. Mars is the only near twin to Earth.
Venus is another candidate for an “Early Earth twin”, as it may have had oceans in the past. There is a remote chance it has life to this day, for instance in the high cloud levels. However, due to its runaway greenhouse effect the surface is extremely corrosive and harsh, raining sulfuric acid. There seems next to no hope of finding out much about early life on Venus or abiogenesis on its surface; at least, nothing like the potential of Mars.
On our knowledge so far it seems likely that there might be other solar systems with Mars like planets. But they are light years away. The prospect of a robotic explorer to these planets, if they exist, is remote, extremely expensive and would take centuries most likely.
Value of a pristine Mars for other fields
Mars could be of immense importance not just to science but also medicine, nano technology, materials science. You simply don’t know what the range of applications could be. So much of our technology began as living products or uses living products in one form or another.
Medicine directly uses many forms of life. Many materials we use in our daily life, including things we think of as non living such as plastics are actually made from products such has oil and coal that were once living organisms. Take away the products of life and there would be little left of all our vast technology.
Life processes are also used in manufacturing, in many ways, and for food. Also, life’s solutions to problems through evolution have inspired many engineering innovations.
So it is highly likely that the knowledge we will gain through studying a pristine Mars, through a massive development of knowledge of Abiogenesis will lead to breakthroughs in technology, medicine, nanotechnology, and many other areas of science.
This is not something that will happen overnight. You need to be patient with scientists. Great scientific discoveries generally take decades, and often generations, to come to fruition.
We might never find out what we lost
By contaminating a currently pristine or almost pristine Mars you throw away all that knowledge, possibly without knowing what you have lost.
That is why at our current so limited stage of knowledge of Mars it is so extremely important to keep it pristine. Later once we have an extensive understanding of the planet we can decide whether it is important to keep it pristine or if it is okay to terraform it or colonise it.
If we don’t go now, will we ever do it?
Enthusiasts for Mars surface colonization often say this. They often treat it as if colonizing Mars is an absolute good, that we have to do it. But as I said in my last blog post, actually in terms of space colonization there is far more room to expand in free flying space habs or orbital colonies than on the surface of Mars.
On the surface, you might have billions of colonists eventually. In space and in orbit you can have trillions of colonists, and likely for much lower cost too due to the high costs and technical challenges involved for the Mars surface. See Space habs could house trillions of people. In the future when space colonization is commonplace, it will probably seem bizarre that the surfaces of planets were considered so important for colonization in the early 21st century.
Moon or orbital colonies close to Earth are more hospitable
The Moon is more accessible and also more hospitable and safer than Mars, especially after the probable discovery of water ice at the poles of the Moon. The same applies for orbital colonies around the Moon or Earth with centrifugal living quarters for artificial gravity (such as the Nautilus X design).
Mars is a natural target for adventurous astronauts who may set up a small colony in orbit around Mars. Humans have a great advantage on Mars, that they can operate the machines on the surface in near to real time. But with the use of telerobotics, it hardly makes any difference if you do that from the surface or from orbit, and the orbital location costs less to get to, and gives easy direct access to the whole planet on every orbit.
For more about all this see my blog post Surface mission to Mars, terrible idea, easily made wonderful
How long will it take before we can know for sure if it is safe to colonize Mars?
So anyway to return to the question, and try to set out a time scale, then at a minimum you need to send instruments to Mars capable of examining deposits. These include laboratory power optical microscopes, miniaturized electron microscopes (which already exist) miniature DNA sequencers, etc.
You need to explore at least some examples of all the significant possible habitats for present day life on Mars.
You need to dig deep into the deposits and the ice caps, not just meters but hundreds of meters. This is possible, there have been studies of ways of doing this robotically and especially with pioneers operating the machinery via telepresence in orbit about Mars, it can certainly be done.
At this stage you may have a pretty good idea of whether life ever evolved on Mars, and whether it still surives. You can’t be totally certain because there could be isolated relic populations or interesting evidence at just one location on Mars (like e.g. the Dawn Redwood on Earth). But you could hope to know enough to have an informed debate about what to do next.
As for the timescale for all this, I would guess perhaps 50 years before we can have this great debate about Mars on the basis of understanding and accurate information. But could be later, could be much sooner. The pace of scientific study and progress is hard to predict.
The great debate about whether to colonize Mars
When all that is done then we will be in a position to have an informed debate about how to deal with Mars - whether it is best kept pristine like Antarctica, or terraformed first remotely seeded with oxygen producing organisms keeping aerobes well away from the planet, or simply colonized as is.
I will probably be on the side arguing to keep it pristine for longer (if I am still alive that is). Others may argue on the other side.
But the main thing is that it needs to be a debate involving all humanity as far as possible. It also needs to be left until enough information is needed to make a decision.
Meanwhile we will find out if indeed we do have the beginnings of this stream of scientific knowledge from Mars and should begin to feel its benefits. Also the first space colonies will already exist and their potential better understood by humans generally. At that stage we will be able to make a better informed decision and will be able to truly understand, at least a bit better, the current and potential future value of Mars.
This debate is something that shouldn’t be decided by scientist, no matter how well informed. It shouldn’t be decided by colonization enthusiasts either, and no-one should pre-empt it by simply mounting an unauthorized mission to the surface of Mars. It is something that needs to be thought out and worked out publicly, because the outcome is irreversible, and affects the whole of humanity.
Projects like Mars One, with just a small change, emphasis on orbital missions to Mars first, could be part of the process of scientific discovery and progress leading to this decision and make it possible to decide sooner in an informed way. These projects could also be part of the great exploration of Mars via telepresence - driving vehicles, digging into the deposits, exploring all the niches and different regions on Mars. Also building the space habitats in orbit around Mars.
Partly pristine Mars
The great debate could also lead to intermediate solutions. First of all you could have factories on the Mars surface. These could supply fuel and other materials to orbital colonies around Mars or indeed to Earth orbit, as well as supplying fuel and materials for repairing and even constructing rovers and robots on the surface. Many factories on Earth are operated mainly remotely with hardly anyone or no-one on the factory floor. These could be operated on Mars just as easily from orbit. This leaves Mars biologically pristine, so retains its value for the study of life and the origins of life. Such telepresence operated factories could be started under current law, so long as the planet is kept contamination free.
Mars could also be Mars formed, made clement for Mars native organisms, if these exist. Or, if it is biologically pristine, or capable of being sterilized of the effects of our missions so far, it could also be warmed up to continue the process of abiogenesis and see what it is like in action. This could also be used to see what the ancient habitats were like in action if there is life still there, relics of the old days like the dawn redwood on Earth.
It could be partly terraformed, just introduce photosynthesizing organisms but no aerobes for instance. This could supply food, and other materials (e.g. wood, plastics, or oil), for the orbital colonies. Or it could be paraterraformed - covered with many domed greenhouses for growing food.
There are many ways you could develop a biologically pristine Mars, depending on what is found there, and what your priorities are.
What if the decision is to keep Mars biologically pristine for ever?
What if we find independently originated life on Mars, or amazingly interesting evidence of early stages that almost reached life but not quite? Should we leave the planet pristine to avoid contaminating it?
I would say why not? Yes, if that’s how it turns out, absolutely fine and could be inspiring, and a great idea, to go all the way to Mars, and set up colonies in orbit around the planet, but never set foot on it at all, to avoid contaminating it.
It is a bit like mountains that are left unclimbed out of respect for the mountain or local beliefs. Not too many of those but the mountains in Bhutan over 6000m are unclimbed. This is possibly the highest unclimbed mountain in the world Gangkhar Puensum with an elevation of 7,570 m.
This would be a future where you have agile rovers on the surface. and increasingly sophisticated humanoid avatars, teleoperated by colonists in the thriving orbital colonies. It is a future where the Martian past and present turn out to be so amazingly interesting, that humans never land on the surface in person, in their physical bodies, to preserve a biologically pristine Mars. I, for one, would find that an inspiring future to live in.
Related blog posts:
Space habs could house trillions
Terraforming Mars needs great care
Surface mission to Mars, terrible idea, easily made wonderful