A deep dive into the 'Zoo Hypothesis'
In humanity's ongoing quest in the search for life in the universe, we have been attempting to come into contact with an alien civilization. So far, we have had no such luck. While this may seem discouraging, it does not necessarily mean that we are alone in the vastness of the cosmos (obviously, we cannot be certain since our signals do not reach that far anyways). In fact, it could even mean entirely the opposite. Perhaps one interesting take on the ongoing debate and search for life in the universe is the idea that we might just be getting ignored by other civilizations in the cosmos. More specifically, we cannot see anyone else, but they can see us. They are just choosing not to communicate or visit, which would explain the lack of responses that we have been receiving in our many attempts to initiate contact.
We can joke around and say that humanity is simply not worth extraterrestrial contact, but what if that is exactly what is going on in the universe? What if we are being observed and do not know about it? Or perhaps we have already been observed, but were left to "figure things out"? As scary and
ISTOCK
intriguing as this sounds, there is actually a hypothesis that was developed around this train of thought, dubbed the "Zoo Hypothesis". The Zoo Hypothesis states that extraterrestrials are intentionally avoiding all forms of contact with humanity, primarily for the reason of humanity being able to develop on its own as a civilization and species, as well as to avoid "interplanetary contamination" (Wikipedia). This is where the name "Zoo Hypothesis" comes from, since this method of observation is similar to the way that humans observe animals at a zoo. In most cases, the animals do not know or care that we are there observing them, nor do we interfere with their daily activities. In this sense, Earth would almost be "locked away" from the extraterrestrial observers.
Now that we have defined what this hypothesis is and what it entails, let's go into a bit of history. Where did this hypothesis originate? We have previously discussed the infamous "Fermi Paradox", which seeks to answer the question: Where is everyone? Well, this
Space Studies Institute hypothesis attempts to answer that question by using the fact that we can't see them, but they can see us, which is the reason for the lack of communication and extraterrestrial visits to Earth. It is several decades old actually, originating in 1973 by MIT radio astronomer John Ball. He published a paper which stated that humanity has been unsuccessful in coming into contact with aliens not due to a lack of aliens, but instead these extraterrestrials have agreed to watch humanity and not interfere with us:
"... the only way that we can understand the apparent non-interaction between 'them' and us is to hypothesize that they are deliberately avoiding interaction and that they have set aside the area in which we live as a zoo. The zoo hypothesis predicts that we shall never find them because they do not want to be found and they have the technological ability to ensure this." [Ball, 1973]
Ever since then, the zoo hypothesis has appeared in numerous amounts of science fiction, and of course with this, there will be criticism. Let's not focus on the criticism right now, but instead the likelihood that such a scenario could actually occur and is taking place in the universe right now, with humans being utterly oblivious to the "Big Brother" watching over us.
At first, it does seem difficult to test something like this, not only because of the assumptions that the hypothesis makes (which will be discussed later), but how would we know if we are being avoided by extraterrestrial civilizations or not? They would be the ones having the technology to mask their presence, yet somehow be able to watch over us. Well, interestingly enough, this hypothesis HAS been tested by astronomer Duncan Forgan at the University of St. Andrews. Forgan has come up with a model that determines how likely it is that the zoo hypothesis is plausible (Futurism.com).
Galaxysalvo on Redbubble
As a side note, the rest of the information on the experiment will be summarized from Futurism.com. I will be linking all of the sources I used and referenced in this blog post at the end.
As previously stated, there are assumptions that the zoo hypothesis makes, which are a bit difficult to determine, but Forgan assumed firstly that multiple extraterrestrial civilizations came together to decide this rule of observing Earth as a 'zoo'. This means that there is another assumption at hand, which is that these other civilizations are aware of the existence of one another, and have chosen to communicate with one another (with their respective technologies). This means that no matter where they are in the universe, their messages have to get from one planet to another, but will be limited by the speed of light (Futurism.com). The last assumption made is with regards to the existence of life in the universe, which "can only be sustained in a galaxy-wide habitable zone, which is around 6-10 kiloparsecs (1 kiloparsec is 1000 parsecs, or around 3260 light-years) from the galactic center" (Futurism.com). Forgan developed a computer program with these assumptions in mind. It randomly placed civilizations on a galactic map, and then calculates the chances of any two civilizations to meet, communicate, and set such an agreement. As far as the results go, the computer determined that 500 civilizations need to exist for the zoo hypothesis to be possible. If there are less, than due to the randomness of the program and sheer distances of civilizations in the cosmos, they would exist too far apart for communication and such an agreement like this to be made. Another thing is the age of the civilizations, due to them having to reach a form of technological advancement in order to be able to communicate across intergalactic space. The computer program determined that they had to be at least one million years in order for a single galactic "club" to be established. If not, then there would not be unity among them. So the final results are that there would need to be 500 extraterrestrial civilizations that are a million years old or older in order for the zoo hypothesis to be remotely possible. So how can we take this information in? Well, with the sheer number of habitable worlds in the universe, there is little doubt amongst the astronomy community that there is life which exists beyond Earth. The trouble comes into play when it comes to intelligent life, since not all life can evolve into intelligent life.
Let's discuss some of the other assumptions that this hypothesis makes, since there are some hefty claims it makes. Perhaps the most obvious thing is that it assumes the existence of other intelligent life in the cosmos. Now, we have previously discussed the Drake Equation, which is used to calculate the amount of intelligent and actively communicating civilizations in the Milky Way galaxy. There are many variables in the equation which are unknown, so there cannot be a current "answer" to the equation, but it does provide a good basis for how we could determine such quantities.
University of Rochester
Aside from the assumption of the existence of intelligent life, the zoo hypothesis assumes that intelligent life is abundant in the universe. In order for this hypothesis to make sense, there would have to be a significant number of alien civilizations that are able to communicate efficiently with each other and come to the unanimous decision not to communicate with or visit Earth. Obviously, they don't have to communicate with each other in order to have this view, but there could always be one civilization that deviates from this and breaks the code of not initiating contact. That way it would make sense for multiple civilizations to talk to one another and decide this. Currently, we do not know the number of intelligent civilizations in the cosmos, let alone the Milky Way galaxy. We may never know this answer due to the sheer size of the universe and its rapid rate of expansion, meaning that everything is getting further away from each other. There was actually a study which determined that intelligent life is in fact incredibly rare in the universe. This study does focus on Earth and the events that led to life being able to exist, but also the unique pattern of events that our planet has endured, such as the mass extinction of the dinosaurs (Forbes.com). If all intelligent life requires evolutionary events such as those that occurred on Earth, then it would seem that it's rare. Additionally, the timescale for intelligent life is brief, since the Sun will become so luminous in around 1 billion years that Earth's surface temperatures will rise way above what can naturally support life. Intelligent life has also arisen on a timescale that is similar to Earth's. It arose around 5 million years ago, while the Earth is around 4.5 billion years old.
The primary point that the authors of the study try and drive home is that the sequence of events that caused multicellular lifeforms to become what we know today as "intelligent life" are very rare. Those events and the evolutionary sequence alone seems quite unlikely to some, causing people to say that the chances of other intelligent civilizations existing are "vanishingly small" (Forbes.com).
University of Calgary
Let's pretend for a second that the universe is teeming with many intelligent civilizations. Another assumption that the hypothesis makes is that these civilizations somehow know about the existence of all the other civilizations and have advanced technologically to the point where they can communicate with each other. This implies that these civilizations are in fact much older than humanity, if we assume that they have also advanced at roughly the same rate that we have technologically. So let's assume that this is true. We are still missing another crucial thing. Even if these civilizations can communicate with each other, they would have had to form some type of galactic organization and agree to avoid Earth so we can develop on our own. This does raise some questions such as why would they choose Earth above all places and how did this agreement start to begin with? This leads into some of the critiques of the zoo hypothesis.
There is one primary critique, which is actually more of a contradiction. If there is a galactic organization or several "cliques" among extraterrestrial civilizations, that means that they are contacting each other, which violates the rule of no contact that is established in the zoo hypothesis. One other thing to question is why these civilizations would establish a rule of no contact to begin with and it only applies to Earth and not themselves. Would they not want to leave each other alone as well and let their own societies develop?
One more primary thing to note about the zoo hypothesis is that aliens may choose to contact Earth once we have passed certain technological, political, or ethical standards that the aliens deem worthy of initiating contact over (Wikipedia). Let's begin to wrap all of this up. What do I think about the zoo hypothesis? Do I think it's plausible? What does it imply for humanity and the future of our contact with extraterrestrial civilizations and societies? Personally, I do not believe in the zoo hypothesis, but I do not think it's "stupid" or anything like that. I think it is an interesting take on why we have not been able to come into contact with aliens, and it does answer the Fermi Paradox, even if it is untrue. I do not think it is true mainly because of the uncertainty of how much intelligent life is out there, if any (which would be more terrifying than if there was). Additionally, due to how large the universe is, I feel that we would exist too far from even the "nearest" civilization, so I am not sure how they would even be able to "watch us". We didn't even consider the possibility that there may be a civilization that does not abide by the rule of wanting to leave others alone, so why haven't they visited or contacted us yet? There is just too much uncertainty for me to really follow this hypothesis. As for its impact on humanity, if it's true, it would probably say a lot about the types of civilizations that are out there, and perhaps maybe it would be a message for humanity to stop trying to establish communication so quickly. There is so much mystery within the universe that we have absolutely no idea what it holds. Only time will tell whether we are truly being ignored or not. Maybe somebody is out there, hearing our message, or our message simply hasn't reached them yet due to the limitations of the speed of light and stellar distances. For now we can just continue to ask "Is there anybody out there?"
If you are interested in any further reading, here are the sources I used to research this incredibly interesting topic! I have also included the papers regarding the studies I talked about as well! Lastly, I have included an old blog post which mention topics that I briefly touched on in this post, such as the Drake Equation and the Fermi Paradox, if you're interested in learning more about those!
Sources:
Drake Equation/Fermi Paradox blog post:
Intelligent life study:
Zoo hypothesis experiment paper: