For over a century, humans have been asking themselves the question, “Do aliens exist?” This question has vexed thousands of astrologists and biologists throughout the centuries, but to the public’s knowledge, no little green men have come down from the stars to answer this question. From fictional stories portrayed in books, comics, tv series, and eventually, large scale movie productions, extraterrestrial life has become a hot and developed interest for the human race, especially with more recent developments in space technology. Are we alone in the universe? If the universe is so big, why haven’t we observed alien life forms? If aliens existed, what would that mean for us?
Scientists have pondered these questions for many years. In 1950, physicist Enrico Fermi first came up with the theory we now call the Fermi Paradox, where he famously said over lunch at work, “Where is everybody?”.
The observable universe is approximately 90 billion lightyears in diameter, and in it, there are over 100 billion galaxies, each with 100-1000 billion stars. Planets are also very common, so there are probably trillions of habitable planets in the universe. This means that the likelihood of life existing in any of these planets is incredibly high, but why haven’t we seen any?
First of all, to narrow things down, let us consider the theory in our own galaxy; The Milky Way. Because the universe is ever–expanding, it would take us billions of years to reach other galaxies, even if we developed fast and advanced spaceships, so let us consider things solely within our home galaxy. In the Milky Way itself, there are over 400 billion stars, only one of which is our very own Sun, which provides us with the many things that we need in order to survive here on Earth. Estimates say that there are about 20 billion stars like the Sun, and about a fifth of them have an Earth-sized planet in its habitable zone. This means that there could potentially be billions of planets with life in the Milky Way.
The Milky Way is in-fact ancient, around 13 billion years old. In the first couple billion years, the galaxy was very inhabitable, with many explosions, but after these, many of the first habitable planets first appeared. Earth is 4 billion years old, which means that there could have been many other planets with life in them even before Earth. This means that there were countless chances for life to have formed in our home galaxy, but it is also more likely that they formed much more earlier than us, which should have allowed them plenty of time to advance their civilization, which means that we should have gotten some signals from them by now.
With that said, statistically speaking, there should be alien life, shouldn’t there? So why haven’t we seen them? The Fermi Paradox is precisely this; it outlines the strange difference in this presumably inevitable discovery of alien life outside Earth and the reality of none encountered so far despite our attempts in reaching out.
One common assumption is that all civilizations will encounter something called "The Great Filter," which is some kind of obstacle so big that all the civilizations which have existed before us have somehow been annihilated once they encounter this obstacle. Perhaps it is some form of self-destruction; when life forms advance to a certain level, they will inevitably destroy themselves, or perhaps we have already passed this "Great Filter" and are the first intelligent civilization to have done so. However, if the latter is true, what obstacle have we surpassed that was so great that no other civilization - from the trillion possible ones to have existed - managed to pass? If it is the former, is it just a matter of time we encounter this "Great Filter"? If so, is it even possible to survive it?
Another common theory is that perhaps alien life forms are simply so different from us that our attempts at communication just could not have been understood by them, even if they are potentially more advanced than us. This also considers the possibility of not being able to have meaningful interactions or communication with them, even if they do exist. Even if they were intelligent, much like how we are intellectually superior to animals, we may not be able to communicate properly. If we were to try to talk to a fish, for example, it would be difficult to create a meaningful discussion. Perhaps, if we discover aliens, that would be what they think of us as well.
There are simply too many theories to consider. Which do you find intriguing? What are your personal thoughts on the existence of extraterrestrial life forms? Feel free to leave comments on the Instagram post accompanying this article.
We cannot say for sure whether or not life outside Earth exists, or even if they have existed at all. But what we can say for sure is that it can exist, and we are living proof of that. Maybe it is only a matter of time before we discover we aren’t the only ones.
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