Our global population, as of 2013, reached a whooping 7.125 billion people, and this number will only continue to grow as the years pass by. The problem is, as our population grows, Earth's limited resources get depleted. In the near future, we may consider finding another planet to live on. Out of all the planets in our solar system, the most likely candidate is Mars.
We can never really hope to terraform the gas giants (Jupiter, Saturn, Uranus, or Neptune) because those planets are made almost entirely of gases, so they have no land for us to live on. Plus, the gasses and excessive pressures would absolutely kill us. So we have to look elsewhere.
Mercury, the first planet in our solar system, is too close to the Sun. We would fry. Similarly, Venus, which is often called "Earth's evil twin," is exceedingly hot because of the very dense carbon dioxide in its atmosphere. We're talking temperatures that hover at about 870 °F (465°C), so that's a no-go.
But what about the moons in our solar system? Europa and Titan, Jupiter and Saturn's moons, have been considered, but they are ultimately too far to the Sun. This leaves us only with Mars. But how likely is it that we could really terraform this world and make it habitable?
The Basics of Turning the Red Planet Blue
Our planet is composed mainly of 4 elements, which are all necessary to support life. These are: Carbon, Hydrogen, Oxygen, and Nitrogen. Hydrogen and Oxygen form water, while Carbon and Oxygen form Carbon Dioxide, which forms our atmosphere (along with Nitrogen and Oxygen). Mars has all of these elements, which sounds great as far a terraforming goes; however, the elements aren't found in the form and quantity that we have on Earth.
Mars also has water, which is frozen in its polar ice caps. If melted, it would correspond to a planet-wide ocean 11 meters deep.
Its atmosphere, on the other hand, is very thin and composed mostly of Carbon Dioxide with a little bit of Oxygen and Nitrogen. Surprisingly, the Mars of today looks very similar to the Earth in its early days. With some work, some scientists believe that we can successfully turn Mars into a habitable planet.
The Mechanics of Terraforming Mars
Terraforming is the process of changing the properties of a planet, moon, or other body to make it similar to that of Earth (and thus, make it habitable). There are two main reasons why Mars is not habitable as of today. First, it has a very thin atmosphere. And second, it is very cold on Mars. To terraform Mars, it would need to undergo some global warming, similar to what we are currently experiencing on Earth but on a much much larger scale.
Scientists have proposed three ways to do this. The important thing to remember in all of this is that these processes will take a long time (some would take centuries):
1.) The first option is to use large reflective mirrors to concentrate the Sun's radiation on Mars' polar ice caps, melting it into liquid water and releasing trapped Carbon Dioxide, effectively increasing Mars' temperature and releases greenhouse gases, which thickens the atmosphere. These mirrors would be about 250 kilometers across, so launching it from Earth would be a very big problem. Scientists are thinking about building these mirrors from materials found in space. This seems unrealistic and a little implausible, but NASA is actually working on creating efficient solar sails, which are a little similar.
2.) The second option is to set up large greenhouse gas factories on Mars. These factories will be powered by Solar Energy and will release greenhouse gases like CFCs, methane and Carbon Dioxide in Mars' atmosphere by using materials found on the Martian soil. This is the same as what we have been doing on Earth since the industrial revolution. Also, factories that convert Carbon Dioxide to Oxygen can also be set up. The problem with this option is supplying these factories with the resources that they need.
3.) The last, and the most extreme option, is to bombard Mars with asteroids which are rich in ammonia. The ammonia will be released in the atmosphere and will then act as a greenhouse gas. This will also release Nitrogen in the atmosphere, making the Martian atmosphere more similar to Earth. To do this, rocket engines will be installed on asteroids found on our Solar System. The problem with this option is, we would not be able to colonize Mars centuries after we have done this because of the destruction that it will cause.
Related to the feasibility of the latter option, theoretical physicist Michio Kaku states,
It might be possible to heat up Mars using nuclear power plants, but this would be a very slow, expensive, and perhaps dangerous plan. A much faster plan would be to divert comets and meteors to Mars. We also mentioned that, if you aim the comet or meteor carefully, you can control its orbit. This means you can gently have the comet or meteor enter Mars orbit, and then slowly descend to the surface as the orbit decays. This means that much of the comet or meteor will burn up in the atmosphere and release water vapor. The point here is that we can accurately aim the comet or meteor so that we can minimize surface damage but maximize energy transfer, which is what we need to heat up Mars.
After we have changed Mars' atmosphere and temperature, we will still not be able to colonize Mars. This is because it would still lack key ingredients like an ozone layer, which blocks some of the Sun's deadly radiation. Luckily, we know some organisms that can release oxygen to form Ozone; however, problems arise when trying to keep said organisms alive on a plant that (essentially) only has some water and the correct temperature - life requires a number of complex processes to survive.
Moreover, Mars would also need a magnetosphere. This would help Mars hold on to its atmosphere by preventing solar wind from stripping it. A magnetosphere is created by the molten metals in a planet's core. Unfortunately, Mars' core is solid and scientists still don't know what to do about this. Yet, despite the fact that the planet couldn't hold an atmosphere permanently, according to Kaku, it could hold one for a few thousand (maybe even a few million) years. That is definitely long enough to get things started, and we will likely develop more effective methods once we are on Mars.
So there you have it. It is theoretically possible to make the Red Planet habitable, if only for a short while; however, we currently lack the technology necessary to complete these tasks. Still, if we invest in the enterprise, it might be possible in the next few centuries (depending on how fast we progress technologically).
What do you think? Will we ever turn Mars into Earth 2.0?
Provided by Brian Koberlein at One Universe at a Time.