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Issue 2 Understanding Science

Terraforming Mars

🕒 5 min

Credit: shaulliv, Flickr.

You’ve probably heard of terraforming, be it in a game, a movie or Elon Musk’s Twitter feed. Even if not, you’re almost certainly aware of all the buzz around Mars and our plans of colonizing it. The feat of modifying an entire planet to better suit our needs would be as taxing as it sounds, but it has become the topic of serious scientific discussion.

So, could we really do it? And how?

Terraforming is the process of modifying a biologically hostile planetary body, specifically its atmosphere, temperature and topography to make it habitable for life as we know it. The term was first coined in a sci-fi context by Jack Williamson, who likely never expected it to leave fiction by any stretch; it did – within his lifetime.

Any object in the solar system that has a planet-like geology, meaning it’s (more or less) round and has a layered internal structure, is called a planetary body. This includes planets, dwarf planets and planetary-mass moons.

For a planetary body to be habitable to most Earth life, it must have extensive amounts of surface liquid water, allow for complex organic molecules to assemble, as well as be a sufficient energy source to fuel the metabolisms of organisms that inhabit it. Mars currently fits exactly none of these criteria. They are, however, very broad. In order to understand what we would need to change to make Mars more hospitable to humans and other forms of macroscopic life, we’re going to look at its three main problems:

  1. its thin atmosphere
  2. its lack of magnetosphere
  3. its frigid temperature

These three features affect each other greatly. We know that Mars used to be much more Earth-like. Rovers have found minerals that can only form underwater as they drove through what seemed to be ancient Martian streambeds. Liquid water requires much higher atmospheric pressure than we see on Mars today. Mars’ formerly thick atmosphere has been stripped away by solar wind over time, due to its lack of magnetosphere and low surface gravity. Its atmospheric pressure is currently only 0.6% that of Earth. That means standing on the surface of Mars is a similar experience to being about 35 km up in the air on Earth – three times higher than most planes fly.

These conditions don’t allow for liquid water to remain on the surface. They also mean astronauts would have to wear pressure suits as well as oxygen masks when working on Mars. Recreating the thick atmosphere of its past would thus be the biggest step in terraforming the Red Planet. A clever way to increase atmospheric density would be to bombard Mars with greenhouse-gas-rich asteroids. This would cause a buildup of extra gasses and a whole lot of warming, starting a self-fueling cycle which leads to our next topic: temperature.

Mars with Phobos and Deimos. Credit: Tokyo Institute of Technology.

On Mars, the average surface temperature is well below freezing. Heating it up would hopefully lead to a greenhouse effect, with the already present CO2 in the atmosphere trapping the heat. This can also heat up the ice in Mars’ polar caps, which evaporates CO2 reservoirs and the cycle repeats. If we wanted to heat up Mars first, we could lower its reflectivity so it absorbs more solar radiation. We could possibly take dust from its moons, Phobos and Deimos, and spread it over the planet, since their surfaces are much less reflective. Alternatively, we could make giant orbital mirrors that would collect incoming solar radiation and direct it towards the surface.

This is all great and fun to imagine – and maybe even quite doable – but ultimately pointless if the newly created atmosphere will just get stripped away by solar winds all over again. NASA’s MAVEN orbiter confirmed that Mars is still losing the little atmosphere it has left, especially when solar activity is high. It is believed that Mars lost its magnetic field due to its core solidifying during planet formation.

One way of creating a faux magnetic field might be to place a magnetic structure in a stable position around Mars so that the entire planet is covered by its magnetic field. Another suggested method is building superconducting rings around Mars, which could create a fairly weak but easy to control magnetic field.

Now, the processes described above are very, very expensive and time-consuming. Even allowing for some groundbreaking technological advancements, warming Mars would take around a century. Subsequently enriching the atmosphere would take us another 100,000 years at the least. It is highly unlikely that an investment on that scale would ever break even. Most of these models suggest technological solutions, but don’t take into account the economic feasibility of actually doing what they propose – they’re essentially just highly advanced daydreams. It doesn’t take much to realize that even with numerous sources of funding, government and private alike, we would struggle to gather enough resources to pull this off.

Lastly, could we really, actually, seriously do it? Terraforming Mars could possibly deplete Earth of its own resources, natural or otherwise. Just using Mars’ natural resources would lead to a tiny change. Mars simply doesn’t have everything we would need to terraform it, so we would need to use materials from its moons and possibly our own Moon, hundreds of comets and carbon-rich asteroids, maybe even Earth and who knows where else.

Various sources of CO2 on Mars and their potential contributions to atmospheric pressure. Credit: NASA Goddard Space Flight Center.

And no, dropping thermonuclear missiles over Mars’ poles would not do the job.

So, will we ever have the infrastructure to pull this off? Spoilers: probably not. We would need to develop some serious science-fiction-level technology, from redirecting asteroids to controlled nuclear fusion, and all of it to just consider the possibility.

Taken together, all of the information we’ve gathered on Mars over the years suggests that we currently don’t have what it takes to terraform it or any other planet. We might be better off focusing on our own planet for now and stick to building localized habitats on Mars. There are many crises on Earth, humanitarian and natural, that require immediate attention, and terraforming Mars would not help their cause.

Do you think we should change Mars to fit our needs? Have you heard of any other potential methods of terraforming? Let us know in the comments.

Sources
  1. Des Merais, D. J.; Nuth III, J. A. et al. (2008). The NASA Astrobiology Roadmap.
  2. Sagan, C. (1971). The long winter model of Martian biology: A speculation.
  3. Brann, T. (2020). MAVEN Maps Electric Currents around Mars that are Fundamental to Atmospheric Loss.
  4. Green, J. L.; Hollingsworth, J. et al. (2017). A Future Mars Environment for Science and Exploration.
  5. Motojima, O.; Yanagi, N. (2008). Feasibility of Artificial Geomagnetic Field Generation by a Superconducting Ring Network.
  6. NASA. Mars Facts.
  7. McKay, C. (2007). Planetary Ecosynthesis on Mars: Restoration Ecology and Environmental Ethics.
  8. Jakosky, B. M.; Edwards, C. S. (2018). Inventory of CO2 available for terraforming Mars.
Recommended

Could We Terraform Mars? by PBS Space Time

By Laura Busak

Laura is a physics student with a love for all things cosmic. She enjoys making and listening to music, reading and generally doing whatever random things she thinks of, often until 2 am.

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