In last Thursday’s companion article, ABRS Ltd. and TEC Partners discussed the integral role space exploration will play in humanity’s future; that, despite the costs and effort involved, colonising planets, moons and asteroids within the solar system and elsewhere in the galaxy are ultimately vital to our survival. Yet, since we’re unlikely to find a perfect facsimile of Earth in our immediate neighbourhood anytime soon, terraforming – the process of transforming a hostile world into a place that can support life – seems to be the best way humanity can safeguard itself against the capricious whims of nature and our species’ self-destructive tendencies.
However, despite the ease with which characters in science fiction settle the Moon, Mars and other celestial bodies throughout the cosmos, in reality, the process is indescribably complicated not to mention expensive and time-consuming (estimates suggest it’d cost up to $3 trillion and take approximately 200 years to make Mars habitable, for instance). Indeed, to even contemplate establishing colonies on alien worlds, there are innumerable challenges that must be overcome first, the most important of which we consider in today’s blog post.
What sets the Earth apart from the rest of the solar system is its atmosphere. Composed of 78% nitrogen and 21% oxygen, along with small concentrations of various other things like argon, it’s responsible for the air we breathe, the life-giving rains that nurture our crops and much else besides; it’s also partially to thank for the steady temperatures we enjoy. And, while ours is certainly not the only terrestrial planet we know of to possess an atmosphere – Venus and Saturn’s largest moon Titan both have dense atmospheres – none of the celestial bodies we’ve detected anywhere in the galaxy hitherto has been immediately conducive to life as we know it. Therefore, for terraforming to work, we must discover the recipe for manufacturing an atmosphere.
For planets and moons that possess only a thin atmosphere like Mars, or essentially lack one altogether like Mercury, numerous methods for creating one artificially have already been identified by scientists; the 3 most popular sound like they’d be part of a bond villain’s nefarious plot and are featured here. Firstly, scientists have proposed using large orbital mirrors to reflect and intensify starlight with the goal of releasing any greenhouse gases stored in the terrain (this would work well on Mars, for example). Another seemingly counter-intuitive technique would see scientists trigger asteroid or comet impacts for the same reasons, with the added benefit of freeing useful elements stored within the impactors themselves. Finally, on certain planets, it might be feasible to liberate these gases by melting quantities of surface ice and permafrost (think of the ending to the original Total Recall). Though it must be said, it wouldn’t be possible to complete any of these 3 processes within human timeframes.
A gentler, more natural way to generate a viable atmosphere is to seed a target planet with oxygen-producing bacteria and other useful micro-organisms. We know this works, since, three and a half billion years ago during the early days of life on Earth, it was these microscopic critters that began oxygenating the planet.
Clearly, renovating an airless rock is fraught with complications. Fortunately, scientists have speculated it’d be far simpler to modify a planet that already possesses a thick atmosphere, even ones as hellish as Venus’s. Since many of the requisite elements would be present from the get-go, it should be a relatively straightforward case of removing the superfluous gases until the ratios are just right. One way to accomplish this would be to develop vast surface oceans which would function as a carbon dioxide sink, sucking up the noxious compounds.
Artificially creating an atmosphere is one thing, but if our new home lacks a magnetosphere, stellar winds would quickly strip it away before it could even gain a foothold; this is what happened on Mars shortly after its birth. You might think this would confine our search for extrasolar habitats to geologically active planets, however, it may actually be possible to resurrect a dormant world.
Just as the friction caused by the gravitational effects of Jupiter on Io – the nearest of its Galilean moons – fuels the incessant volcanic activity the tortured moon is known for, scientists theorise we could harness these same forces and restart a planet’s core with the introduction of a suitably large, artificial moon. There are sure to be plenty of large asteroids in the average star system that could be set in orbit around a dormant planet or, alternatively, we could build one from scratch using smaller pieces of space debris.
Should placing an object in orbit prove too difficult or costly, it might be possible to kick-start core rotation (the process by which our magnetic shield is powered) by injecting it with huge amounts of radioactive material.
Wonderful as these plans are, they’re both well beyond the capabilities of our current technology. For this reason, it’d probably be easier to colonise planets on a piecemeal basis, at least initially, establishing cities beneath protective domes. Obviously, the major downside of this approach is that it would restrict our presence on new worlds to specific locales and leave us entirely reliant on technology for our survival, nevertheless, it would ensure we have a limited presence on a wider variety of worlds, starting us on the path toward becoming a truly interstellar species.
Estimates suggest there are somewhere in the region of 100-400 billion stars in the Milky Way galaxy alone meaning there are literally trillions of planets and moons just waiting to be terraformed. However, Earth-sized worlds aren’t necessarily the most common type of planet in the cosmos, so if we do colonise the galaxy one day, we might have to get used to unfamiliar gravitational conditions; and this is, potentially, a rather serious problem.
Post-mission analysis of ISS astronauts has already alerted us to the fact that long-term exposure to zero-G weakens our bones, muscles, organs and is generally harmful to our rather fragile bodies. Of course, even the smallest moons and asteroids have some form of surface gravity so zero-G shouldn’t be a problem once we make landfall, still, scientists suspect life on a low-gravity world could cause similar if less acute problems for any animal and plant species introduced into such an environment. Moreover, there’s no way of knowing what impact reduced gravity would have on human and non-human embryos.
Frustratingly, it’s hard to imagine we’ll ever be able to generate artificial gravity on a planet-wide scale, thus any solutions we come up with have to be more specific. Rather than attempting the seemingly impossible, we could build isolated cities and rural settlements in strategic locations encased in the same protective domes mentioned previously, assuming we eventually discover the secret to anti-gravity technology and can scale it up to encompass hundreds of acres of land. That being said, in conditions that are similar to Earth, perhaps it’d be possible to simply mitigate the negative effects reduced gravity has on our physiognomy by augmenting human beings directly; reinforcing bones with man-made alloys, strengthening muscles with implants and supporting organs with specially designed bacteria.
We’ve finally perfected our surroundings, now all that remains for us to do is find something to eat and drink. Theoretically, water shouldn’t be hard to come by in the long or short term. It’s reasonable to expect there’ll be millions upon millions of nearby comets we can harvest for precious H20 to see us through the early stages of terraforming while looking further into the future, the atmosphere seeding process should provide us with plenty of sustainable surface liquid water.
Creating a sustainable source of food is a bit trickier. There might be vast populations of photosynthesizing plants already in situ, however, it might not be possible to rely on these as a source of food. For one thing, it wouldn’t be sensible to reserve large quantities of plant matter for the purposes of sustenance whilst atmospheric transformation is still in progress, lest we hamper the oxygenating process, moreover, there’s always the chance native soil conditions will be inimical to the fruit and vegetables that grow on Earth, lacking the correct mixture of nutrients to cultivate them effectively. Hydroponics offers an effective solution to the latter problem, though this approach would cost significant amounts of time and money to implement on an industrial scale; fertilisers would also help.
Meanwhile, cattle and animals in general, couldn’t be introduced until the ecosystem has developed to a sufficiently advanced level, limiting our access to meat. Protein substitutes in the form of lab-grown meat or vegetarian-friendly alternatives would, therefore, be integral in the early days of the terraforming process unless we were to establish dome-enclosed farms separate from the intrinsic conditions of the planet.
Up till now, we’ve discussed the various foundational elements individually, but it’ll take a combination of the technological advancements to successfully terraform another world. Because of this complexity, self-contained domes (which I’ve mentioned a few thousand times by now) or even orbital stations are surely the way forward, at least in the relatively near future.
The field of terraforming is undoubtedly exciting, however, as with all ground-breaking scientific ventures, the moral and ethical implications are of paramount importance and should be carefully considered. Questions such as ‘how much of any given world should we colonise’ and ‘do we interfere with living planets’ must be answered before we take any definitive action. Furthermore, given the amount of societal and ecological problems on Earth at the moment, it’s fair to ask whether our goals of cosmic expansion are a little premature. This might be true, though personally, I’d still sign up for an interstellar colonising mission in a heartbeat.