Earth’s population is projected to grow to 9 billion by 2050. This brings into question how much real-estate and how many resources Earth can actually provide for humans in the long run. There are many Earth-based answers to overpopulation ranging from regulated birth-rates to utilizing unconventional real-estate such as oceans and air. While the idea of creating ocean or air-based cities is tantalizing, I don’t believe they will be the best long term solutions, and regulating birth-rates inhibits freedom. By staying on Earth we are only putting the continuity of humanity at risk by not creating alternatives. Tech billionaire Elon Musk has recently unveiled his plan for putting humans on Mars. His primary argument is that we need to create a “backup” of Earth in the event that a catastrophic disaster wipes out its population. Water and air-based cities are wise and should be considered for the near future, but there are additional options we need to consider. Musk has already set into motion the most obvious option, and that is to get humans on the next best candidate planet for habitation. In the meantime we will need to boost public interest in his mission. But for those (like myself) who are not ready to venture to the red dessert planet, we should consider closer, more comfortable options, such as Earth-orbiting space colonies. And for those who want more options than Mars, we should consider the many other planetary bodies within the solar system such as the Moon, asteroids, or other planetary moons like Jupiter’s Europa.
My favorite solution to overpopulation involves building orbital settlements in specific areas around Earth’s orbit, and after that, around various places in the solar system. These colonies can be built large enough to accommodate hundreds of thousands to a few million people each. Each colony could sit comfortably around stable pockets of gravity known as Lagrange points which exist around planetary bodies. Every massive object in the solar system has five Lagrange points where a large object could be placed stagnantly. If we decided to place a space colony at each Lagrange point they could accommodate anywhere between 1 million to 10 million people in total. Once we decide to spread further into the solar system however we can begin utilizing the Lagrange points of the various gas giants and their moons. Say we decided to place just 15 space colonies throughout the solar system. This would allow for about 30+ million people to offset Earth’s population. 30 million people is only .3% of a population of 9 billion, but it’s a start. In order to get 500 million people off of Earth we would need about 250 average sized space colonies spread throughout the solar system. Depending on how large we decide to make space colonies, we could potentially off-set about 10 percent of Earth’s population in the next century. I believe this is feasible due to the abundance of real-estate in space.
Orbital settlement from the movie ‘Elysium’
In case you’re wondering how orbital settlements work, I will offer the basics. Space colonies are essentially self-contained “biospheres” that attempt recreation of Earth’s conditions at optimal levels. They are depicted in many modern works of science-fiction. Think of the ring-worlds in the ‘Halo’ video games series, the orbital space station in ‘Elysium‘, or the cylindrical space colony Cooper Station at the end of the movie ‘Interstellar’. Space colonies use a combination of artificial gravity and climate control to produce near-perfect Earth conditions. Most space colonies will probably contain homogeneous weather patterns and will stay stagnant at a comfortable, mid-Spring temperature, but terrain and climate can definitely vary based on preference or natural causes. The “Sun” will most likely be artificial depending on the location and shape of the structure. Not only would orbital settlements create alternative habitats for humans, but they will also offer novel, breathtaking views of whatever planetary body they’re orbiting.
As I write this, news is circulating of a proposed space-nation called Asgardia which is petitioning to be the first space colony in Earth orbit. It is only in idea phase but has already garnered 455,000 signatures from people hoping to become the first citizens of Asgardia. This project, founded by a single man named Igor Ashurbeyli, represents the beginning of serious public interest in orbital space colonization. NASA believes that the speculative space-nation of Asgardia would sit well at Earth’s Lagrange 1 point. For more information visit the official website where you can also sign the petition yourself.
As mentioned before, plans are already underway for colonizing Mars. This has been the most obvious target for exploration and colonization since the beginning of the space race. Plans have been outlined through books and movies for decades. Recently, Elon Musk caused renewed interest and competition to reach the planet with his announcement that his company SpaceX will begin missions to Mars by 2020. Now, multiple private and government space agencies are racing to be the first to set humans upon it. Musk hopes to have millions of colonists on Mars by 2050. Soon, tickets to Mars will be as cheap as buying a car. Mars will develop cities, culture, and sustainability which will make it even more attractive to prospective migrants. A billion humans could inhabit the planet by the end of the century.
Mars is favorable because of its proximity to Earth. It’s about half the size of Earth and double the size of the Moon. It possesses a nice template for a future biosphere. Mars used to feature running water and maybe even life before its atmosphere all but dissipated millions of years ago. Although it is inhospitable now, I don’t doubt the human ability to adapt to it by using technology. Closed ecological systems, or biodomes, can be as big as they need to be. Light-weight, flexible exosuits can allow safe travels to and from the many landmarks and cities on the desert planet. Eventually, Mars’ climate could be manipulated towards an Earth-like state via a process known as terraforming, which I will cover later.
The Moon is another nearby object capable of harboring human life. It is less appealing due to its complete absence of an atmosphere and lack of geodiversity. I suspect far fewer people will opt to migrate to the Moon, but it will be a necessary location for setting up scientific and operational bases. The majority of the Moon’s population will most likely consist of scientists and workers helping to keep facilities functioning. Likewise, Mercury and Venus, despite their harsh conditions, can also be set up for colonization. Mercury is not the most appealing planet, but scientists may want to set up camp in order to conduct research. Venus is the other closest planet to us, but its atmospheric situation is the complete opposite of Mars’. Its extreme temperatures make landing on it a a difficult task, but like Mars, it can potentially be terraformed. Additionally, Venus has a thick cloud layer with cooler temperatures closer to the top. It could be possible to create sky cities in the top layers of Venus’ atmosphere.
The outer gas planets have an abundance of interesting moons that are viable worlds on their own. Europa, a moon orbiting Jupiter, is an ice world with a global ocean underneath. Colonizing Europa, like the Moon, Mercury, and Venus, probably won’t be at the top of the list of preferred destinations, but it will be a necessary world to establish bases and small ice villages. On Europa, igloo-like biodomes can be created on the ice, and subsurface cities can be built in Europa’s ocean. Saturn’s moon Titan has a thick atmosphere and lakes of liquid methane. Methane doesn’t have the same special properties that water does, but it is still a top candidate for the discovery of extraterrestrial, microbial life. There is no doubt that Titan will soon be colonized with scientists. There are estimated to be about 180 moons orbiting the various planets in our solar system, and just about all of them are worlds that humans can land on and create habitation in some way. I suspect many moons will be used as scientific stations or tourist destinations. They may not be a direct solution to overpopulation, but they can be used as motivation to journey into and colonize deep space in general.
Aside from moons, giant asteroids are another potential habitat for colonization. Ceres is one such object in the Asteroid Belt that is actually so big it’s considered a dwarf-planet, much like Pluto. In the far-reaching science fiction TV show ‘The Expanse’, humans have colonized the dwarf-planet Ceres for the purpose of supplying water to Earth and Mars. According to the show’s wiki page:
the station has a population of approximately six million permanent residents with an extra one million transiting through at any given time. Eight hundred to a thousand ships are docked on Ceres every day.
‘The Expanse’ portrays a reality that is not too far-off from our own. Asteroid mining may be the new Gold Rush in the coming decades. Congress has recently implemented the Commercial Space Launch Competitiveness Act which would allow space companies to claim ownership of resources they mine from asteroids. Companies such as Deep Space Industries are already devising plans to begin asteroid mining missions in space. It won’t be long before colonies will be necessary in the Asteroid Belt to house thousands of workers and travelers involved with resource gathering enterprises.
Most planetary bodies in the solar system are naturally inhospitable to life in general. Living within biodomes on Mars for instance wouldn’t be the most pleasant long term situation. Having almost nothing protecting someone from the harsh conditions of the outside environment will not promote migration to the planet. But humans have technology and centuries worth of scientific knowledge about how the climate on Earth works. It’s possible that someday, humans will learn to manipulate the environment of other worlds to better support life. Terraforming is the process of engineering a planet’s climate to match conditions on Earth. The necessary final step towards Mars colonization will be to terraform it. Many ideas have been proposed ranging from nuking the planet’s poles in order to melt the ice and release CO2, to creating massive machines that pump greenhouse gases into the atmosphere. Whichever technique is chosen, the first Martians will be responsible for guiding their planets terraforming process.
Terraforming process of Mars
Before any world can be terraformed however, humans will need to have solved the environmental problems with the Earth today. Climate change is currently the biggest problem facing humanity, and we are the prime factors causing it. Once we have found a way to stabilize our own planet, only then will we be able to design artificial biospheres for space colonies and technology for terraforming worlds.
Once humanity has inhabited just about every practical world in our own solar system, it will then become necessary to seed the rest of the galaxy with human life as well, assuming there are no other forms of intelligent life in the galaxy to compete with. Eventually, humanity will need to formulate plans for a mass diaspora to other solar systems similar to our own. Finding potential candidates will not be a problem. Thanks to the Kepler space telescope we have already surveyed the sky and have found thousands of exoplanets in our galaxy; many of them deemed potentially habitable. In fact, the star system closest to us, Proxima Centauri, was recently discovered to possess an Earth-like planet of its own. The world-famous physicist Stephen Hawking has already initiated plans focused on sending a reconnaissance probe to this neighboring star system. We will likely send many more reconnaissance probes to the star systems that are most likely to possess habitable worlds before ever sending humans. After the reconnaissance missions, I imagine a moment in humanity’s future where hundreds of “generation ships” disembark from our solar system on a journey to the countless planets discovered in modern times by the Kepler space mission. These generation ships will house thousands of brave people ready to colonize the first exoplanets. Hopefully by then we will have developed engines capable of sending these massive ships to the nearest stars in a matter of decades, because the distances between stars are depressingly large. It could be argued that leaving our solar system is humanity’s manifest destiny, because if we aren’t to colonize the rest of the universe, then what a ridiculous waste of space. To quote Carl Sagan:
The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars.
Concept art for a Generation Ship