Featured Image: The beloved extraterrestrial from 1982 is quite relevant to our current search for intelligent life outside Earth.
Thursday, 23 May 2019, New York, NY – Some of you may have heard of the Fermi Paradox, the puzzling question of “Where are the aliens?” It seems like a simple question, but despite decades of research and investment, we still haven’t found any evidence of alien life, and probably won’t for a very long time. Here are a few basics about the Fermi Paradox that you might not already know.
The Fermi Paradox, or the question of “Where are the aliens?”, was first posed in 1950 by Enrico Fermi, a physicist and researcher at the Los Alamitos National Laboratory in New Mexico. Despite the name, the Fermi Paradox is actually not a paradox, because it does not contradict itself, it’s just an ordinary question. However, it’s called a paradox for one important reason. Because of the vastness of the universe, it seems logical that the universe is teeming with aliens, that we should be able to find aliens everywhere, but there is no evidence of their existence. It seems illogical that we are unable to find evidence of aliens, and thus, the Fermi Paradox is referred to as a paradox.
The apparent “shortage” of aliens is also puzzling due to the sheer size of the universe. The universe is 93 billion light years across. The Milky Way Galaxy is a ridiculously small fraction of the universe, and despite this it contains up to 400 billion stars. If we assume that each one of these stars has fifteen planets orbiting it, that would mean, theoretically, that there are 6 trillion planets in the Milky Way Galaxy. Even if only 0.1% of these planets (1 in every 1,000) have habitable conditions that can support intelligent life similar to humans, there would still be 6 billion habitable planets in the universe. That’s about one habitable planet for every 1.25 humans (theoretically).
With this many potentially habitable planets, that would mean a lot of potential alien civilisations. So Fermi assumed that at least some of these civilisations would have, as SETI cleverly put it, “a modest amount of rocket technology and an immodest amount of imperial incentive.” Within a few million years (which is just a few weeks on the astronomical scale), an alien race could create an empire encompassing the entire Milky Way Galaxy. What’s more, these hypothetical aliens would be able to control the galaxy’s energy, and police the development of other civilisations. If a civilisation under its control became too advanced, or threatened the legitimacy or existence of the galactic empire, that civilisation would be destroyed by the controlling galactic empire.
The Milky Way Galaxy
Hopefully, this dystopian scenario is not actually happening. As far as we know, there are no aliens. But that’s an unsatisfying answer, so let’s discuss some theories as to where the aliens are.
The first theory is that humans are alone. Despite the vastness of the universe, it’s entirely possible that there just isn’t any other life in the universe. We truly are alone. Or, at the very least, we are the only intelligent life. Life may exist, but it just takes the form of tiny microbes without the capacity to create a civilisation. This is actually the most likely solution to the Fermi Paradox, as zero evidence of alien civilisations has been discovered thus far. Interestingly, Fermi’s personal belief was that humans were the only intelligent life in the universe.
The second theory is that of the Great Filters. A Great Filter is a massive obstacle that a potential civilisation must overcome, or otherwise it will die. Examples of Great Filters include infectious pandemics, nuclear wars, severe pollution, climate change, or overpopulation. The Great Filters are portrayed as a pyramid, or hierarchy, where filters start out simple, but as the civilisation advances, the filters become more and more difficult to overcome. Some hypothesise that, eventually, all civilisations reach a great filter that is impossible to overcome, and all civilisations die out upon reaching it. If most alien civilisations die out within a short time after emerging, this could explain the absence of aliens.
The third theory is that space is huge. The universe is 93 billion light years in diameter, so it’s extremely likely that we haven’t been looking far enough, long enough, or looking in the right places. Our current form of communication, radio, is only detectable in the immediate area around Earth. What’s more, we have only been looking for aliens for around 80 years, which is not a very long time. Alternatively, we may have been accidentally searching for aliens in the parts of the universe with the lowest levels of activity.
The fourth theory is that it’s the aliens fault we can’t find aliens. Whether it be that their technology is too advanced, they’re not transmitting signals, or the aliens are deliberately avoiding us. Aliens may consider radio to be ancient technology, and may prefer more advanced forms of communication that we humans have not yet mastered. The aliens might not be transmitting signals, but rather, are only listening for signals. This is actually what’s happening on Earth, as our efforts to listen for signals far outpaces our efforts to transmit signals. Perhaps the most interesting theory is that the aliens are deliberately avoiding us. The aliens may see us as juvenile or underdeveloped, and deliberately avoid us because of those designations.
What do you think is the most likely explanation for the Fermi Paradox? Leave your thoughts in the comments below. We’re looking forward to reading them!