Can We Farm Mars? Should We?

As a gardening (and eating) fanatic, the first thought I had when I moved into my new home was, “Can I make my property fertile? And if so, how?” I explored ways to improve my soil so that my harvest would be more abundant. I built trellises so my beans and grapes would have places to climb. I removed those malicious pest species that every farmer despises. More simply and more beautifully: I became a husband to my land.

When reading the recent NASA news of liquid water flowing on Mars, the question came back to me: “Can we make Mars fertile, and if so, how?”

Just think: We could be the workers of land never before touched by life, effectively imbuing that land with life. Imagine eating a red Martian apple grown from red Martian soil looking up at a night sky full of sparkling dots, one of those being Earth. Not only is it tasty, it’s beautiful.

I’m not by any means the first person to ask questions of Mars’s fecundity. It’s something that has been on the minds of scientists since interplanetary travel became a possibility—and among writers long before that. And now many space agencies, both federal and private, are being more intentional about how to answer those questions. However, when we talk about plant life on Mars, we have to discuss certain limitations.

The first problem we encounter is the most obvious; Mars is really, really cold. The average surface temperature is approximately -60°C (-80°F), but the temperature there is also incredibly variable, ranging from 20°C (70°F) on an equatorial summer day to -125°C (-195°F) on a winter evening at one of the planet’s poles.

I know what you’re thinking: “Let’s just stick to the equator! Seventy degrees is positively balmy!” But, even though the equator can be 70°F at noon, when the planet’s surface faces away from the sun, the equatorial temperatures can plummet to -100°F. Obviously, most vegetation needs more than twelve hours between frosts to grow and develop, so that’s going to be an issue.

The next hurdle to clear will be the planet’s atmosphere. The composition of Mars’s atmosphere is actually favorable for plant life, relatively speaking. Its primary constituent is CO2—a necessary ingredient of photosynthesis—composing about 95 percent of the total atmosphere. But the main problem is that Mars has less than 1 percent the atmospheric density of Earth. This means that Martian atmospheric pressure is reduced to about 0.6 percent of Earth’s atmospheric pressure. The bad news here is that as atmospheric pressure decreases, so does boiling temperature. In other words, water boils at about 10°C (50°F) on Mars. It seems nuts, but we can see that very principle in action here on Earth. While pure water normally boils at 100°C (212°F) at sea level (0 ft), on the top of Mt. Everest (29,029 ft), where atmospheric pressure is significantly lower, water boils at a mere 71°C (160°F). From the perspective of a poor college student, at that elevation it takes about 2 extra minutes to make a bowl of Ramen noodles.

The third water-related Mars bummer involves the latest Martian news. NASA’s scientists found the evidence of liquid water flowing on the planet by looking at the recurring slope lineae (RSL)—waxing and waning gullies that form on Mars’s surface during warmer seasons. The researchers examined the chemistry of the RSL and found that the water that created them contained ionic compounds (that is, salts). These salts alter the chemistry of the water, allowing it to remain liquid at lower temperatures and pressures. That effect is helpful on Earth for things like road salts. But for agricultural purposes, it’s totally unhelpful. The salts found in Martian ground water contain chlorine, which is terribly lethal to plants. As it happens, we use many of the same salts as herbicides here on Earth. It turns out we haven’t found water; we’ve found plant poison.

So sometimes the temperature is too low and water solidifies in the form of ice. And sometimes the temperature is within the range necessary for pure liquid water but the water quickly boils due to low atmospheric pressure. Furthermore, just when everything seems to be going great and water manages to remain in its liquid state, the compounds it contains are toxic to organic systems. This, as you can imagine, is no good for the water-loving organisms found on Earth.

It’s quite the unhappy series of events. But it may be redeemable.

A popular topic of conversation in theoretical astronomy as of late is the possibility of terraforming. Terraforming is the idea of taking a planet like Mars, one with an environment hostile to Earth-based life, and creating on it an atmosphere with the composition and density to support liquid water—and thus life.

The usual proposed methodology is to first flood the planet’s atmosphere with greenhouse gases to fix the density problem. In the case of our red neighbor, we have come up with several ideas, from dropping hydrogen bombs to setting large mirror satellites in orbit above the planet to melt Mars’s polar ice caps using sunlight. Both of these would release much of the carbon dioxide and other greenhouse gases locked in their solid states at the planet’s coldest regions. Once the density of the planet’s atmosphere was suitable and stable, the next struggle would be to adjust the atmosphere’s composition.

This would be the trickiest part of the whole plan. When you talk about chemical concentrations and quantities in the atmosphere you have to keep in mind all the chemical reactions that could irreparably damage the planet. It’s obviously a delicate bit of business, and the most compelling methodology proposed is to replicate what happened on our planet.

At some point in Earth’s development, it looked a lot like Mars looks now: barren with a hostile atmosphere. The idea is to transform Mars using the same astronomical, geological, and biological forces that uniquely turned our planet into a lush, lively sphere.

We could introduce photosynthetic organisms to balance the amounts of carbon dioxide and oxygen in the air. And we could use bacterial pioneer species to reduce the amount of heavy metals in the ground and expel ground nitrogen in the form of N2 gas. As these originally introduced organisms remake the environment into something more favorable, we could introduce more corrective species to create a positive feedback loop—a process by which a small change reinforces the cause of that change. Then we’d have the beginning of a largely self-regulating biosphere: Earth 2.0.

Of course, nothing like this has ever been done. It’s still deeply within the realm of theoretical science. But as our understanding of the red planet’s needs grows, so does the plausibility of it becoming habitable.

This is a big possibility. For humans to become a multi-planet species is quite a thing to ponder. No doubt everyone on Earth will have a strong view on whether we should become a multi-planet species. But for Christians, the question will be a bit different, and more pointed. Is it our responsibility as stewards of creation to redeem Mars?

If we believe that from and through God all things were made and all things persist, then Mars is not outside of God’s creative jurisdiction. And if we believe that humankind has been made in the image of God, serving as the means by which he cares for all of the things he created and loves, then we must admit that all things under human authority are to be treated with love and pure intention.

Now, this mandate doesn’t necessarily command us to terraform a planet; it simply petitions us to care for the things that we have. It doesn’t tell us if we should colonize Mars; it only informs us how we should do it.

If and when our science catches up to our imagination and we find that we have either the desire or the need to make a move to the red planet, the ethic of stewardship should dictate all that we do. If we are ever able to inhabit Mars and make it a fruitful, verdant home, we should acknowledge and receive it as the gift that it would be. Meanwhile, we don’t have to wait to thank God for the planet and what we’re learning about it.

As stewards, the responsibility of environmental redemption falls to us. It is the work of God to order and reconcile, and, until he does that finally and for all, we do it simply and for him.

Seth Ratliff is a hiker and writer living in Bristol, Virginia. He is co-director of the (Audio) Liturgy Podcast and sometimes blogs.

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