Rest assured, there are other worlds like ours.
Thousands, even hundreds of thousands…millions, even? In our galaxy alone. Some may not be exactly like Earth; more nitrogen, less oxygen or water, more argon. They might be a little larger, a little warmer or cooler. But really, that’s hardly an issue. So you’ll be a little bit heavier, so you might breathe a little deeper. Not a big deal.
Well, while these planets surely exist, none of them are here. None are nearby. Indeed, none are even close to within what we could call a reasonable distance at the moment. The closest of these planets may (or may not) be Proxima Centauri B, orbiting its diminutive star about 4.2 light years from here. That means that, with significant investment of research effort and material resources, we could conceivably get there in a little less than 40 years.
Countless theorists, from Carl Sagan to Stephen Hawking, have suggested that we must colonize space in order to ensure our survival as a species. For the time being, that limits us to the planets we have here, in the solar system. Unfortunately, that reality presents its own unique set of problems.
Where do we go, then? There are few possibilities. Venus is similar to Earth, size-wise. Yet when one considers its thick atmosphere, infernal surface temperatures, and frequent acid rain, it hardly looks like home. The longest-lived probe ever to reach the Venusian surface, the Soviet Venera 13, managed to transmit for all of 127 minutes before being destroyed. Then there are the moons of the outer planets. Some, like Europa and Enceladus, appear to harbor vast quantities of life-giving water, yet these barren satellites would require herculean feats of terraforming to be hospitable to humans. One science fiction author presented the idea of humans living on Europa in submerged cities that hung for the underside of the icy crust, like stalactites.
That leaves but one workable possibility for the near (relatively speaking) future. Mars. It’s smaller than Earth, but not too small. It’s further from the sun, but not too far. It has water, though most of it lies frozen at the poles. It has an atmosphere, however thin. It has soil suited, based on recent studies, to growing potatoes, if little else. So it’s not ideal, but it could work. Think of it, perhaps, as the cosmic equivalent of “a real fixer-upper”.
How, then, do we “fix up” this potential new home? No doubt the first human explorers, and indeed the earliest settlers, will have little choice but to live sealed into pressurized habitats: human-sized terrariums, with recycled air and water, and greenhouses for growing food. Asking the population of an entire planet to live that way forever, though, seems deeply cruel. So, what then?
Up to this point, the solution seemed obvious: terraforming. It would not be overly difficult to make Mars resemble Earth…comparatively speaking, at least. We would need to thicken the atmosphere, seed it with oxygen, perhaps through photosynthesis from introduced algae. The ice caps would have to be melted, at least partially, to create surface water. Then would come plant and animal life, imported from Earth. It’s possible, certainly, yet it would still represent likely the most tremendous undertaking in human history.
So, what if, instead of adapting our new home to suit our needs, we adapt ourselves? What if, instead of fixing the place up, we just learn to live with the new house as it is?
In his recent book, Future Humans: Inside the Science of Our Continuing Evolution, Dr. Scott Solomon, an evolutionary biologist with Rice University, suggests that humans who move to Mars will quickly evolve into a separate species, possibly within as few as six thousand years (a veritable blink of an eye, on an evolutionary scale). These changes might be unnatural, including perhaps cognitive enhancements from technology or drugs, as well as natural responses in the form of changes in pigment and bone density.
It is, of course, quite possible that changing ourselves would be far more feasible, at least in the near term, than changing Mars. Changing human skin pigmentation, say to something more orange or red, would protect human colonists on Mars from the planet’s increases solar radiation due to its thinner atmosphere. Thicker bones would develop in response to lower gravity. Cognitive enhancements would be more conducive to a civilization largely confined to space suits and sealed habitats. Yet, what would that mean for humanity?
Some of these modifications may eventually make humans living on Mars not only well-suited to life on their planet, but particularly ill-suited to life on ours. The gravity on Earth, for instance, might feel uncomfortably heavy to humans born on Mars. So, the question is, just how permanent will permanent residency be on Mars? Are we truly ready to condemn an entire population of humans to never return home? Would those humans even consider Earth “home”?
Perhaps it’s difficult for us to understand. Earth, after all, is the only home we have ever known. It’s uniquely suited to our comfort, for we evolved to be comfortable here, as humans on Mars would, in time, grow to be comfortable on that planet. Yet, perhaps this segues into another pertinent question here: would allowing, or even encouraging, humans on Mars to evolve into a separate species be counterproductive?
Let’s remember what Sagan et al envisioned when they spoke of the need to colonize space: preserving our species. If the humans on Mars ultimately evolve into a separate species, would these “Martians” still be considered human? Would they see us as being part of their species? It might be that settling Mars in order to preserve humanity would ultimately prove pointless, if humanity must transform into something different in order to survive.
From there, of course, we get into the real red meat of modern science fiction: the conflict between Earth and Mars. The Expanse by James S.A. Corey is certainly the most recent notable work to feature Earth-Mars tensions as a major plot device, yet it’s far from the most recent, and indeed may not even be the most notable. From Star Trek to Babylon 5, the idea that Martians will, inevitably, come to their own unique sense of identity (and thus into conflict with Earth) has been a staple of sci-fi for decades. And while there may not be any Martians yet, we find ourselves today in a truly remarkable situation: we may well be the first generation to face the stark realities of such conflict.
We can only hope that, when the time comes, our experiences with colonial influence and racial tensions here on Earth will prevent us from making the same tired mistakes once again.