Let's think about Earth for a little bit. At any second, there could be a global catastrophe that wipes out a large amount of the human population. It's a dark thought to think about, but it's not unlikely. Another instance of doom is the inevitability of the Sun expanding into a Red Giant and devouring our planet in 5 billion years. Of course, we're unsure if humanity will even be around at that point or if we'll have evolved into something completely different, but the possibility still exists. Lastly, we could completely ruin our planet through global warming. We've already seen some of the intense effects of climate change, but if we don't change our ways soon, we will surely cause some irreparable damage to Earth. What do we do in instances like this? Surely we want to continue living on for as long as possible don't we? The answer may lie within the realm of science fiction. Although "fiction" is becoming much closer to "reality" than we think.
We have all heard people talking about "Moon colonies" or "Mars colonies," but just how possible are these? Where will humanity go when Earth simply becomes uninhabitable? Is it possible for us to leave our planet behind and start a new life elsewhere? Are there any ethical implications? How much will it cost? There are many questions that arise from the topic of space colonization. There have been arguments for and against the subject. Let's talk briefly about a couple of arguments in favor of space colonization (according to Wikipedia):
The survival of human civilization and the biosphere in the event of a planetary-scale disaster (natural or man-made).
The availability of additional resources in space that could enable the expansion of human society.
These are both solid arguments, as we would want our society to be able to progress, and at some point, we will most likely exhaust the resources of Earth and need to go elsewhere. We would also want humanity to be able to thrive for as long as possible, so it would make sense that we would try and expand to another planet when Earth is no longer feasible for us. However, there are also the arguments against space colonization (according to Wikipedia):
The colonization of the cosmos may be likely to enhance the interests of the powerful (major economic and military institutions).
Exacerbate already pre-existing detrimental processes such as wars, economic inequality, and environmental degradation.
These are also solid arguments and lie more on the ethical side of the debate.
Regardless of stance, there are some key reasons as to why space colonization may become a reality in the future. According to Wikipedia, here are the reasons why space colonization may be considered in the future:
Human Survival: In the case of a devastating event on the planetary scale (whether man-made or natural), humanity would be able to survive long-term on another planet (or moon). Theoretical physicist Stephen Hawking argued for space colonization as a means of saving humanity. He predicted that humanity would go extinct in the next few thousand years unless space colonies were established. He stated that we face two options: long-term extinction or colonize space within the next couple hundred years.
As previously mentioned, we as a species cannot survive on one planet alone. We would have to expand out into the cosmos if we want to survive long-term (millions of years). In our current age, we are running out of resources on Earth, which means at some point it will become very difficult to sustain our growing population. Additionally, if humanity were to enter a global nuclear warfare, we would risk possibly wiping out large parts of the human population, but if we had a space colony, we could restore human civilization, or even prevent this from happening altogether.
There was a theoretical study conducted by a small group of researchers in 2019 to determine the long-term trajectory of human civilization. This trajectory could be maximized in about four steps:
Create plenty of space colonies could be established in habitable locations- in outer space or on planetary bodies away from Earth. These colonies could remain dependent on Earth while they are getting started.
These colonies would eventually become self-sustaining, so they would be able to continue surviving if the civilization on Earth dies out.
Colonies can develop and expand their habitation by themselves (possibly by terraforming).
The colonies could self-replicate and establish new colonies in further out in space. This process could then repeat itself at an exponential rate throughout the cosmos.
Needless to say, human survival is a large factor in driving the interest for space colonies.
Resources in space: There is no shortage of resources in space, whether it be materials or just energy. "The Solar System alone has, according to different estimates, enough material and energy to support anywhere from several thousand to over a billion times that of the current Earth-based human population" (Wikipedia). The same principle can apply to exoplanets as well, however we would need to develop the necessary technology in order to reach them, due to the distances from our Solar System.
Asteroid mining is something that has been discussed, and if space colonization becomes a reality, it will certainly be of use to us. We would be able to find the necessary materials in order to establish our space colonies, without having to look to Earth for resources (especially is we have used them up by that point). NASA also believes that asteroid mining will save a large amount of money for space exploration. There is an endless amount of potential for the growth of human civilization if we use extraterrestrial resources.
Other reasons: Additional reasons for establishing space colonies would be:
Further expansion without consequences: As a species, we would be able to grow without destroying resources on our own planet. We would not be harming any pre-existing wildlife or populations. (This is of course with the knowledge of space lacking life, but could change).
Alleviating overpopulation: As our population grows, the demand for resources will as well. Unfortunately, those resources do not come in an infinite supply on our planet. If we were to build space colonies, we would not be limited to what Earth can supply. Although Earth does have plenty of non-renewable resources, space colonies would still be able to alleviate some of the resource demand.
Another question which arises from the topic of space colonization is just how we could perform such a task. Indeed, it sounds daunting when you think about it. Moving off of our planet to establish a new home somewhere else, that too, in a location where we may have to simulate some of the conditions found on Earth. So how could we do it?
Well, let's talk about a very popular subject: Terraforming Mars (our "sister" planet). It's an interesting concept, because we would essentially have to create an Earth-like environment from scratch (including creating an atmosphere). A paper titled "The Terraforming Timeline" outlines a plan for how we can turn Mars into our new home. The paper was written by Aaron Berliner from the University of California, Berkeley, and Chris McKay from the Space Sciences Division at NASA Ames Research Center. Essentially, we would have to warm the planet to a value close to Earth's average surface temperature, and then we would have to produce sufficient levels of oxygen for us to be able to breathe. These would be the two main terraforming steps; however, it would be very difficult for us to be able to produce that much oxygen in a short amount of time unless there is some sort of technological breakthrough. Before we can even begin to terraform the surface, we need to take "pre-terraforming" actions, according to Berliner and McKay.
Essentially, we would need to investigate the Martian surface in order to determine the amount of water on the surface, the amount of carbon dioxide in the atmosphere (and in ice form in the poles), and the amount of nitrates in the Martian soil (phys.org). In order to warm the surface up, we would need to deliberately put a large amount of carbon dioxide in the atmosphere (sound familiar?). They claim that it would only take around 100 years to warm Mars. This part of the terraforming process is considerably shorter and "easier" than the next phase, which consists of creating an oxygen-rich atmosphere for humans to be able to breathe in. Obviously, on Earth, the high levels of oxygen and low levels of carbon dioxide are due to photosynthesis, which relies on energy from the Sun. They estimate that this process would take between 100,000 and 170,000 years. This timescale was determined due to the lack of efficiency of how Mars traps incident solar radiation. Obviously, we would need major technological advancements to be able to pull off something like this. It may not even happen in our lifetimes.
Artist rendering of a Mars terraforming plant [Credit: National Geographic]
Valeriy Yakovlev, an astrophysicist and hydrogeologist from The Laboratory of Water Quality in Kharkov, Ukraine offers a counterargument. In his paper titled "Mars Terraforming-the Wrong Way," he argues that we should create space biospheres in low Earth orbit that would rely on artificial gravity (like an O'Neill Cylinder) to allow humans to grow accustomed to life in space (phys.org). This is a sound argument because we are only used to how it feels to stand on the surface of the Earth. We would be susceptible to solar radiation and lower gravity. This could have a negative effect on our bodies (as seen in astronauts who spend long time periods in space). These effects would include bone loss and muscle degradation. It also also unclear what effects space would have on children that are born in it. In his paper he states: "If the path of space exploration is to create a colony on Mars and furthermore the subsequent attempts to terraform the planet, it will lead to the unjustified loss of time and money and increase the known risks of human civilization." Additionally, he points out the challenges of creating a suitable environment for humans living in space (vehicles, housing, etc.). If we made these artificial habitats in low Earth orbit, we would not risk contaminating Mars' biosphere (if there is a presence of bacterial life), and we would become accustomed to life in space. He also believes that these habitats can be creates in a reasonable time frame of 10 to 30 years.
As for my final thoughts on the subject, I am all for space colonization. As long as we are not bringing our human "filth" to any extraterrestrial life, I don't see many problems with it. I actually think it could be more beneficial for us than harmful. We are explorers, we have been explorers for all of human history. It's in our blood. I want humanity to be able to find out more about where we came from: the cosmos. Hopefully we will become explorers of the cosmos.
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