Mars is a disappointing hellhole lacking practically everything we need to stay
alive. It looks like we’ll only ever have small crews spend a miserable time hidden underground.
Except, we could terraform it into a green new world. But to solve the planet’s problems,
we first need to make it worse and turn it into oceans of lava with gigantic lasers.
This isn’t a far-fetched science fiction tale. Terraforming Mars is possible, on the kind of
time scale our ancestors built great monuments in. If humanity solves some of its pressing
problems and ventures into space to expand into the solar system, this may not be that far off.
Ok. So how do we terraform Mars quickly? Well, It’s complicated.
Mars is dry and has no soil to grow anything. Its atmosphere is too thin to breathe or protect from
radiation, giving you a high risk of cancer. So to turn it into a new home for humanity,
we have to give it a proper atmosphere, similar to Earth’s. It should be made of 21% oxygen,
79% nitrogen and a tiny bit of CO2, at an average temperature of 14°C and under 1 bar of pressure.
We have to create oceans and rivers and then the ground has to be weathered into fertile soil to
host living things. Then we need to install a biosphere on the surface and prevent it all
from being undone by installing protective measures that can stand the test of time.
It’s difficult. But a big laser makes it a lot easier.
Challenge 1: The Atmosphere
Some 4 billion years ago Mars had a nice oxygen-rich atmosphere and was home to vast
oceans and rivers. It held onto it for several hundred million years before it
got blown away. Ultraviolet rays broke down the atmospheric gases and then the oceans,
until they were swept away by solar wind. Today Mars is a dry, barren wasteland.
Luckily a sizable portion of the water is frozen in deep reservoirs and in the polar ice caps,
enough to create a very shallow ocean. And enormous amounts of oxygen are bound
as minerals in the Martian rocks, like the oxygen in the iron oxides
that give the planet its rust-red colour, as well as carbon dioxide in carbonates.
To free these gases, we need to reverse the reactions that lock
them away by using thermolysis, which occurs at temperatures as
high as on the surface of the Sun. In short, we want to melt Mars’ surface.
The best way to do that would be to put lasers in orbit aiming their beams down on Mars.
The most powerful laser today is the ELI-NP,
able to produce beams of 10 Petawatts of power, for a trillionth second.
To melt Mars we need a laser twice as powerful, that runs continuously. The easiest way is to use
a solar-pumped laser that can be powered directly with sunlight: At its core are metal-infused glass
rods that absorb energy and release it as a laser beam. If we build an array of mirrors in space,
about 11 times the size of the United States, we can focus enough sunlight onto them to melt Mars.
Let’s do it!
As the lasers hit the surface, about 750 kg of oxygen and some carbon dioxide emerge
from every cubic meter of rock melted. If we are efficient our lasers only need to
melt through the top 8 meters of the surface to get enough oxygen.
It would look terrifying. The skies would be shrouded in storms,
while the ground would glow red-hot, criss-crossed by currents of lava.
Tireless laser beams sweep over the landscape, leaving trails too bright to look at. After they
pass, the ground cools quickly. A strange snow falls: the ashes from all the elements
that solidify as they cool down, like silicon and iron. Mars is still a cold planet at this point.
A happy side effect of this inferno is that all the water in the polar ice caps and even
deep underground rises into the sky as hot steam, forming clouds that rain down over
the entire planet. They would wash out the nastier gases from the atmosphere,
like chlorine, and carry away harmful elements that accumulated on the surface. In the end, they
would form shallow oceans, saltier than on Earth. We might need to do an extra clean-up afterwards.
It would take about 50 years of continuous lasering to create our oxygen atmosphere. We
could use this opportunity to dig deeper in some places to create the basins for salty oceans or
rivers and spare some landmark features like Mons Olympus and Valles Marineris.
We’re not done though.
The resulting atmosphere is nearly 100% oxygen and only 0.2 bar. It’s hard to
breathe and very flammable. To make it similar to earth and a lot safer,
we need to add a lot of nitrogen, which Mars is lacking sadly. We have to import it.
The ideal source is Titan, a large moon of Saturn, covered in a thick atmosphere that’s almost
entirely nitrogen. We just have to move 3000 trillion tons from the outer solar system to Mars.
While that’s not easy, it is doable. To process that much of Titan’s atmosphere,
we have to construct giant automated factories, on its surface powered by our lasers to suck in
the atmosphere and compress it into a liquid. This gets pumped into bullet-shaped tanks,
which a mass driver shoots all the way to the red planet, where they explode and mix
with the oxygen. We’ve already been able to send individual missions to Saturn in just a few years.
With enough resources, it should be possible to complete the task within 2 generations.
Of course it would be much more convenient to have nitrogen left
over from terraforming Venus on the side: we explained this in detail in another video.
So, about a century after the start of the terraforming process,
we have a breathable atmosphere that has the right gases. If the liberated CO2
isn't enough to warm it up to temperatures we can stand, we just add some super greenhouse
gases. Mars at this point resembles a black marble from all the cooling lava,
spotted with growing oceans and red patches where the old surface remains untouched. It’s
still a wasteland, no better than a desert on Earth. We need to fill it with life.
Challenge 2: Biosphere
Installing a biosphere on a new planet is very difficult. Unexpected interactions
between species or sudden diseases can destabilise it to the point of collapse.
We would probably begin by seeding our young oceans with phytoplankton. Without competition,
it would bloom rapidly, filling up the oceans to become the bottom of an aquatic food chain.
They can be followed by tiny zooplankton,
then by fish. Maybe even sharks and whales. If things go well, life in the oceans will thrive.
Life on land is harder. Plants need nutrient-filled ground to sink their roots
into. But most of the surface is the congealed remains of lava and ashes. We could wait for
thousands of years for water and wind to grind it down into finer sands or try to do it manually.
But we want to be quick. And we have a big laser. Turning the beam on and off
in rapid succession would cause the ground to quickly heat up and contract, which breaks it
into smaller and smaller pieces. Add a bit of water, and you get a sort of dark mud.
Into this mud, we can mix fungi and nitrogen-fixing bacteria. They’re
able to absorb nitrogen and convert it into nitrate compounds to feed plants.
The first plants we want to bring are native to volcanic islands on Earth,
since they are perfectly suited to the laser-blasted Martian landscape.
Eventually, the enriched mud becomes the foundation for grasslands and forests. In
Mars’ lower gravity, trees can become very tall very fast. Their roots gather the nutrients
they need and then dig deeper to turn more rocks into soil, forming a self-sustaining ecosystem.
At this point we can slowly introduce more plant varieties, insects and animals. Not mosquitoes
though. The new biosphere needs to be maintained to prevent it from falling out of balance. If
plants grow too quickly and absorb too much carbon dioxide, the planet cools down too much.
If key species die out, we could see populations collapse faster than they could recover. On Earth,
other species would move in to fill the void, but our Martian biosphere is not as flexible.
It takes hundreds if not thousands of years before Mars becomes a stable environment.
But eventually the planet will have the potential to sustain large human colonies. With air,
water and food available, we can finally call Mars – black,
blue and green – our home. A giant, volcanic island in space.
Will it last though?
Challenge 3: The long-term future
There is a problem we haven’t addressed: Mars’ core does not produce a magnetic field, so it does
not have enough protection from solar radiation or cosmic rays. This becomes dangerous for the
long term health of Martian populations. So as a final step, we need an artificial magnetic field.
It doesn’t have to be huge like Earth’s. It
just needs to deflect the solar wind enough so that it doesn’t touch Mars.
The easiest way is to construct a magnetic umbrella far ahead of Mars that splashes the solar
wind to the sides. A big, superconducting ring powered by nuclear facilities is all it takes.
It would orbit at the Mars-Sun L1 point, keeping it constantly in
between the Sun and Mars and protect the new atmosphere. And that’s it!
Terraforming Mars would take some work, hefty resources and probably a century or
ten but it would be the first time we’ve lived in a home designed and
shaped solely by us and for us. A first step towards our future among the stars.
The first step we can already take down on Earth is learning more about
the physics and biology needed for such a project.
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