Terraforming Mars: will we ever make it?
- Second part In the first part of this discussion, we talked
about the origins of the concept of terraforming and the need, in the case of Mars, to start
a warming process by releasing the carbon dioxide trapped in the polar ice.
In this second part, we will review the methods proposed to do so, concluding with an analysis
of the actual feasibility of the operation...
Another way to raise the temperature of the polar ice cap could be to sprinkle it with
a black powdery substance (coal dust).
This would reduce the amount of sunlight reflected by the ice caps into space and result in consequent
heating of the ice.
According to a NASA study, this way the caps could be fully vaporized in a couple of centuries.
Yes, but where to find this "black powder"?
Some say sending it from Phobos and Deimos, which are among the blackest bodies in the
Solar System; or introducing dark extremophilic microbial life forms such as lichens, algae
and bacteria.
However, Mars is already the second darkest planet in the solar system, absorbing more
than 70% of the incoming sunlight, so the space to darken it further is small.
And dig thousands of tons of dark regolith on Phobos and then spread it on the ice ... this
too must not be a joke ... Not to mention even crazier proposals, such
as triggering nuclear reactions inside Phobos to turn it into a small star.
Or to detonate nuclear bombs in the craters of ancient volcanoes, to make them active
again.
Or to change the orbit of some asteroids to make them fall on the polar caps ...
And speaking of bizarre (and dangerous) ideas, just recently, Elon Musk proposed bombarding
the poles of Mars with hundreds of atomic bombs to release all the CO2 contained ... A
proposal that fortunately NASA promptly rejected, proving that to obtain some result would require
thousands of explosions a day.
In short...
The ideas to awaken the planet by raising the temperature are there, it is true, but
the fact remains that these are projects that at the moment are ALL far beyond our technological
possibilities, and that probably will still be for several centuries.
Terraforming a planet like Mars also requires knowledge in climatology and planetology that
we are far from having.
Man today is unable to control the Earth's climate and we must admit that we suffer from
it much more than we control it.
The red planet is also plagued by two major handicaps that could ruin any terraforming
effort.
Mars is a small planet, has just one-tenth the mass of the Earth, and its gravitational
field has proved unable to prevent a significant portion of its precious atmosphere from escaping
into space.
Even managing to form a dense atmosphere at the right point, the problem will then be
to be able to hold it back!
Unlike the Earth, then, Mars no longer has a global magnetic field.
The dynamo effect has in fact ceased with the rapid cooling of the metal core (in turn
linked to the small size of the planet).
On Earth, this magnetic field forms a shield that protects the atmosphere from the abrasive
effects of the solar wind.
Despite their genius, pessimists say, humans will never be able to reactivate the Martian
magnetic field (even if it is a study in which Jim Green, director of NASA Planetary Science
Division, proposes to place a magnetic shield dipolar at the Lagrange point L1 of Mars to
create an artificial magnetosphere around the planet), and the planet will never again
be able to rely on this formidable natural umbrella to prevent the erosion of its atmosphere.
Faced with the absence of a global magnetic field and the weakness of gravity, man will
probably have to surrender forever.
A very harsh sentence, this ... but for the sake of argument let's assume that we have
somehow managed to trigger the greenhouse effect on Mars, increasing the atmospheric
pressure to at least one-tenth of that of Earth and allowing the water to form pools
here and there…
What should be the next step?
Well, at that point, if we ever get there, the plan is to rely on infantry, that is,
on bacteria!
Microorganisms seem to be the ideal actors for the terraforming of the red planet.
As on Earth, they could release ammonia or methane, gases that are much more efficient,
from the point of view of the greenhouse effect, than carbon dioxide.
Laboratory simulations have already shown that some species of methanogenic bacteria
can cope with reduced atmospheric pressure and find the nutrients necessary for their
survival in the Martian soil.
Planetary engineers will also be able to exploit the formidable resilience of the bacterium
Deinococcus radiodurans.
This microorganism can survive doses of radiation 3000 times higher than those that would kill
a human and also has a high tolerance to drying.
If 1% of the planet is covered with bacteria and their efficiency in converting solar energy
into a chemical compound is 0.1%, 1 billion tons of methane and ammonia will be produced
annually, and this will raise the temperature.
10°C every 30 years.
Moreover, the methane and ammonia produced by their metabolism will also provide good
protection against UV rays.
Once this stage is reached, the benefits for future settlers will already be very significant.
The next step towards total terraforming will consist of the radical transformation of the
atmosphere, introducing oxygen and nitrogen, and eliminating carbon dioxide.
This is the well-known process of chlorophyll photosynthesis, thanks to which the plants
of the Earth supply oxygen to the animal world.
To increase the oxygen content of the Martian atmosphere, we can disseminate cyanobacteria
on the surface of Mars, used to living in extreme conditions, such as in Antarctica.
Cyanobacteria are among the first living things on our planet.
For two billion years, these organisms reigned supreme on the surface of our planet and profoundly
changed the composition of the earth's atmosphere.
Well, by capturing CO2 and releasing oxygen through their photosynthetic activity, they
can also gradually change the composition of the Martian atmosphere.
Why not?
Two particularly resistant cyanobacteria species have attracted the attention of scientists.
The first, Chroococcidiopsis, is a cyanobacterium capable of tolerating extreme drought, high
salinity, as well as significant temperature contrasts.
On Earth, Chroococcidiopsis lives in deserts, buried a few millimeters on the surface of
translucent rocks (sandstones), which then play the role of a moisture trap and ultraviolet
shield.
The second species, Matteia, is a drying-resistant cyanobacterium that has the property of dissolving
carbonate rocks to find protection.
Matteia is also able to fix atmospheric nitrogen if this compound is scarce in its environment.
Whatever species of algae are selected for terraforming, they must first bring the oxygen
partial pressure to the threshold value of 1 mbar.
At that time, higher plants will be able to develop freely on the surface of Mars.
These plants, made more efficient thanks to genetic engineering, will be acclimated to
the harsh Martian conditions and will produce even more oxygen.
So the partial pressure will eventually exceed 120 mbar.
The amount of oxygen will then be enough for the first Martians to leave their respirators
in the locker room before going out!
within several decades, using such an approach Mars could be transformed from its current
dry and icy state into a warm, slightly humid planet capable of supporting life.
The air would not yet be breathable for humans, but they would no longer need space suits
and instead could travel freely outdoors wearing ordinary clothes and using a simple respirator.
Large habitable areas could also be built under huge inflatable domes containing breathable
air, while simple, hardy plants could thrive in CO2-rich soil and spread rapidly across
the surface.
Over the centuries, these plants would bring more and more oxygen into the atmosphere,
favoring the growth of more complex plants and the presence of an increasing number of
types of animals.
These are not just hypotheses ... It was discovered that terrestrial lichens located inside the
Mars Simulation Laboratory of the German Aerospace Center survived exposed to environmental conditions.
And they did so by clinging to the cracks in the rocks and empty spaces of the simulated
Martian soil, adapting and demonstrating the same activity they would have done in their
natural environment!
Could it, therefore, be that the best way to think about the terraforming of Mars is
through the intensive use of microorganisms and elementary plants, perhaps genetically
modified, rather than through brutal planetary upheavals?
Be that as it may, A terraforming discussion would be incomplete without the question "Should
we do it?".
Just because terraforming is technically possible and would not directly destroy an ecosystem
does not mean that it must necessarily be done.
Mars is beautiful and interesting as it is, and perhaps we should leave it this way to
allow future generations to study it.
The billion-year-old Martian landscapes tell the story of Mars and the solar system to
anyone who can read them, and their destruction would be a terrible loss to science.
The icy beauty of its deserts must be preserved.
There is also the risk of biological contamination.
If there is microbial life on Mars, the arrival of terrestrial organisms or the upheaval of
the Martian environment by us could lead to their disappearance.
And even if the absence of life were proven, some argue that the rocks and the shape of
the landscape itself have an intrinsic value.
This is an extreme view called cosmic preservationism.
In this, the anthropocentrists are obviously much more hasty, for whom everything that
man needs is good.
From this point of view, the terraforming of Mars remains acceptable as long as it is
in the service of man.
Despite these questions, the terraforming of Mars could be an inevitable event in human
history.
Our planet, the Earth, is fragile and isolated.
A cosmic catastrophe, such as an asteroid impact, could wipe out humanity and its history
in seconds.
Isn't man's goal to explore, discover new worlds, settle there and thrive?
Mars is a new world, a new frontier, a starting point for a new humanity.
According to Carl Sagan, terraforming should not be a response to the overpopulation affecting
our planet.
The ticket for a one-way trip from Earth to Mars is too expensive.
It also makes the same point about mineral resources.
Transporting them to Earth would be too expensive.
The ethical problems posed by terraforming are innumerable.
But one thing is certain: a drastic change in the conditions governing Mars' surface
could be undertaken with 22nd-century technologies.
Will man want to change the face of Mars?
The question remains open ...