There are many people on Earth who dream of moving to Mars and terraforming it, be it a science fiction writer, entrepreneur or inventor like Elon Musk. But what will it cost and how real are such dreams?
In the entire universe known to us, there is only one planet on which a complex and familiar intelligent life can exist - the Earth. And although very distant worlds orbiting other stars could potentially be Earth-like and probably even inhabited, we will not be able to get closer to them anytime soon. What about the worlds in our solar system? The most attractive today is considered to be Mars, which in the past, according to scientists, was very similar to Earth. Perhaps with a little help, he could be like this again?
While the very idea of terraforming Mars sounds tempting, there are many reasons for pessimism. Is this feasible with modern technology? Will the planet's natural resources be enough to transform it into a place where humans can live? Is it real at all?
Of course, Martian soil itself can be toxic, but there is a fair amount of toxic soil on Earth as well. There are only a few factors that determine what can inhabit an environment: pH, moisture content, and the ability to absorb the elements, molecules, or nutrients the environment needs versus its ability not to be poisoned by what is in it. On Earth, soil can be "cured" or rehabilitated by simple chemical solutions, and there is simply no reason to doubt that we can do something similar on Mars. And this is probably the easiest part. As soon as microorganisms appear that can thrive in Martian soil, even if it is a small fraction of what is on Earth, we will be on the right track to finding a new home.
But Mars also has a bigger problem: it's dry. It’s not that there’s no steam or ice - they’re definitely there in certain quantities. The problem is getting large volumes of water in liquid form on a regular basis. Despite the fact that Mars has salty liquid water during the day - what we see from the growth of lines on the Martian escarpments - most of the time the water is either frozen or in a gaseous state. As far as we know, liquid water is essential for life on Earth, but it is not on Mars.
The physical reason is simple: Mars' atmosphere is too thin to support liquid water on the planet's surface. Liquid water needs a certain value of atmospheric pressure: at least about 1% of what is on Earth. Mars has only about 0.7% of the Earth's atmospheric pressure, making the formation of liquid water nearly impossible. The small amount of water on Mars is due to the salinity of the surface and the fact that craters can go deeper down, where there is a little more atmosphere and pressure. If a person were left unprotected on the Martian surface, then the liquid in his body would boil, since the conditions on Mars are below the Armstrong limit.
Soil remediation requires the creation of a self-sustaining macroscopic life in a habitable biosphere, oceans and other stable sources of water on the surface, and more atmosphere.In order for Mars to have an atmosphere comparable to that of the Earth, it is necessary that the Red Planet has about 140 times more of it than it is now: about 3.5 thousand teratons, or 3.5 x 1018 kilograms. The satellite Uranus Pak has about the same mass, and by volume it is about 70% of the earth's atmosphere. In addition, to get to the planet, we will need to transport a lot of mass there - preferably nitrogen and oxygen.
But even if you add that much atmosphere, there is another problem: Mars does not have a magnetic field to protect it from the solar wind. As confirmed by the Maven mission, the Red Planet continues to lose the remnants of the atmosphere due to the collision of charged particles with it, which leads to the loss of various molecules. Today, Mars' atmosphere is mostly carbon dioxide, which is heavier than the nitrogen and oxygen molecules in our atmosphere. If we want to terraform Mars, we will not only need to add a lot of atmosphere, the water needed for life, and then chemically transform the soil to make it habitable, but also protect it from outside influences, right?
This may not be the case. The fact is that in all physical problems it is important to remember about quantity: ask not only about what is happening, but also about the speed of the processes occurring. Of course, the solar wind "blows" the atmosphere from Mars, but the question of how quickly this happens was first answered by the Maven mission: approximately 113 grams every second. Of course, during solar storms, this figure can increase tenfold, which seems really fast. But if you think about how long it will take to blow off the terraformed atmosphere from the planet, the answer is: incredibly long - at least hundreds of millions of years. Instead of creating a super-strong magnetic field, you can focus on adding particles to the atmosphere to replace losses.
Of course, under no circumstances should you think about leaving Earth and moving to Mars. Any work on terraforming the Red Planet is more energy intensive than what can be done to save the Earth. No matter how badly we pollute our planet or even harm it, it is still the most habitable world in the solar system.
Do not get too carried away with the thought that Mars is a great place to relocate in case the Earth becomes completely unsuitable for humans. The Earth is our main planet, our home, and it is our responsibility to deal with earthly problems in order to increase humanity's chances of long-term success and prosperity. Mars may well be a long-term challenge for this same problem, but creating a more massive atmosphere is perhaps the most difficult challenge for us. However, if you can pull this off, and then add oceans, rain and fertile soil, then a thriving ecosystem will be around the corner.