Terraforming Mars is a favorite of many science fiction novelists. However, since we cannot even keep the climate of our already habitable Earth stable, how could we hope to create one from scratch on Mars? Let’s have a look.
Life on Mars
Mars is farther out from the sun than Earth. A year on the Red Planet is about twice as long as one on Earth, but it does still have four seasons. Mars is also much smaller than Earth, with only 38% of Earth’s gravity at ground level. It is also much colder, with mostly sub-zero temperatures, and where Earth is two-thirds water, Mars is a rocky ball.
So, basically, Mars is a cold, dry, low-gravity hell-hole. Even if we were to get astronauts to Mars — a nine-month trip — they would still need heated shelters, some way to get water, and something to make the air breathable. You see, I nearly forgot to mention one of the biggest problems of living on Mars: there is barely an atmosphere and what is there is toxic to humans.
So, the hurdles to take to live on Mars as it is today are gigantic, but that’s a topic for another day. Let’s see what it would take to change Mars into a place we could live on without space suits, an even more gigantic task.
Water
As noted, water on Mars is a problem. There isn’t a lot. Even the ice you see in some pictures is usually made up of a combination of water ice and carbon-dioxide ice — it’s that cold. However, that isn’t the whole story. There is actually more water on Mars than you’d think. There are the ice sheets on the poles, but also a lot of water is hidden beneath the surface.
The problem, however, is getting that water liquid and in the air. The atmosphere of Mars is almost non-existent — see below — and it is cold on Mars. You have to heat it up, and create an atmosphere, and then the water would probably come out.
If that isn’t enough, you could try to knock watery asteroids from further out in the solar system out of orbit and crash them into Mars. It’s not easy to do, but it is probably doable with our current level of technology. Some think it’s even possible to create a lake by 2036.
But that’s not the biggest problem.
Temperature
Okay, so we might have water. It’s still bloody freezing on Mars. These days, we have some hands-on experience in using greenhouse gases to warm a planet. We could do that on Mars. Heck, most of the current atmosphere there is carbon dioxide. . As we all know, that’s a greenhouse gas, so that could be used to heat Mars. So, why isn’t the temperature rising already? The short answer: the atmosphere is too thin.
To increase the effect you could add other chemicals. One proposed approach is — again — to drop in some asteroids. This time, ammonia-rich ones. Others include using methane — which is abundantly present on Jupiter’s moon Titan, for example, which is a ten times more potent green house gas. Fluorine chemicals will also do the trick. Those are powerful greenhouse gases, in fact (which is why we don’t want them in fridges these days).
But, it is important to note the scale we’re looking at: Mars is a planet. You need enormous amounts of whatever you’re using. Dropping a few asteroids isn’t an easy process, and mining Titan for Methane might be possible, but I think there are some big technical hurdles there as well, and it would all have to be automated, and the amounts you need are, as said, enormous.
But okay, let’s move on.
Beathable air
Air is another big hurdle in terraforming. Earth atmosphere is 78% nitrogen, 21% oxygen and 0.9 % argon. In case you’re wondering where our greenhouse gases are: they’re in the remaining 0.1%.
Mars atmosphere is 95% carbon dioxide, 3% nitrogen, and 1.6% argon, with only 0.2% oxygen. So, not very breathable. If you wanted to make it breathable, you’d have to radically change the composition.
And remember, we added even more crap in the step above, to heat the planet. So, after we heat it, we have to start turning CO2 into O2, and if we use ammonia, we’re in luck, that will already result in more nitrogen.
Again, converting the composition of an entire atmosphere is hard. I’m no expert, but the task seems incredibly daunting. And not something you can do over the weekend, and probably not over a century. You also need to achieve some kind of eco-balance, or things will quickly spin out of control again. But that’s not all.
Solar winds
Finally, we come to the big kicker. The atmosphere on Mars is incredibly thin. So thin the water would immediately boil off our tongues if we opened our mouths there. Also, the CO2 would kill us, of course.
The atmosphere on Mars used to be thicker, actually, but the red planet has a big problem. A terraforming-show-stopper of a problem: It has no magnetic field.
“Oh, well,” you might think. “so compasses won’t work.”
That is true, but worse than compasses is that a magnetic field also protects the atmosphere from being stripped off by solar winds. I won’t go into the details, but the short version is that Mars’s atmosphere is mostly being blown away, continually.
And this is a huge problem. Whatever you tried to fix on Mars, it would eventually be undone. We can’t dump a magnetic-field asteroid on the planet either. The magnetic field of Earth is caused by iron spinning around in the Earth’s molten core. Mars had such a mechanism after it was formed, but that mechanism seems to have shut down millions of years ago. You can’t turn it back on again — although, some fantasize about drilling down and injecting nukes in the core of Mars.
There are two solutions that might be viable, though: putting two gigantic magnets in orbit around mars in the right Lagrange points, or creating a plasma torus of charged particles in Mars orbit. Both might work, but are not trivial to create. Our current technology isn’t good enough.
Conclusion
Mars is not a fun place to live. And making it a fun place to live is hard. Really hard. I don’t see it starting in my lifetime, and even if we do, it won’t be finished for lifetimes after that. Honestly, I think we have bigger problems at the moment, like global warming on Earth. And wars. And inequality.
I applaud looking to the stars and trying to conquer the solar system, but I don’t see terraforming Mars as something that will gain us anything at the moment. It’s fun to think about, but we won’t live to see people walk on Mars without space suits, nor will many generations after us, I think.
