Have you ever taken a look at the star ridden night sky and had the urge to scream at the top of your lungs saying, “IS THERE ANYBODY OUT THERE?”. Or maybe you are tired of the lifeforms on Earth and want to discover something unique. Look no further as in this article you might get an answer to your question (and in order get terrified).
Extraterrestrials have been a fascination for humankind for millennia if not aeons. They had a profound effect on our literature, history, culture, entertainment sectors and most important of them all astrology and cosmology in physics. Although other worldly intelligent life wasn’t in the spotlight of physics before the 20th century, it increasingly became a field of interest over the years as we developed technologically. The search for extraterrestrial life has been going on for decades now starting from some of the very first space programmes but to no avail. From analysing specimen data to sending literal spaceships at certain planets, scientists have left no stones unturned. Yet we don’t have any clue on whether there really is life out there. So, is everything in vain? Let’s take a look at a paradox and theories created by some of the greatest minds of human civilization:
Fermi Paradox:
Recent astronomical discoveries indicate that the universe is 13.8 billion years old and 93 billion light years or 8.8×1026 meters long containing 2 trillion galaxies harboring about 200 billion trillion star systems. All these numbers are unfathomable for our tiny human brains but one aspect which any human being might agree on is there should be extraterrestrial lives. But the question is where? This was the question raised by physicist Enrico Fermi, who won the nobel prize in 1938 for his contributions to nuclear physics (Yes, one of the scientists from “Oppenheimer” movie who was involved in the Manhattan project), during his last days in 1954. The paradox mainly revolves around 2 questions:
(1) Why are there no aliens or their artifacts to be found on Earth or in the Solar System?
Explanation: Human civilization has been on Earth for around 300,000 years and today we have reached the capability of doing interplanetary travels. To reach the closest star system Proxima Centauri, we will need about 70 thousand years with current technology. But it is assumable, that since technology is improving at an exponential rate (from wheels to spaceships in the span of 2000 years!) we might reach the peak in a short time and so shall our interstellar travel time decrease. Thus, it should take about 5 million to 50 million years to colonize the whole galaxy (huge numbers for us but very miniscule compared to the scale of the universe)! But given the amount of red dwarfs (stars almost at the end of their lifetime) at the center of the Milky Way galaxy, where are the intelligent lifeforms at? Where are their relics of once ruling our galaxy? Even if they deem that interstellar tours are resource consuming, they should have some sort of technology like probes or satellites to explore the galaxy and also outside of it, right?
(2) What about advanced civilizations outside of the Milky Way galaxy?
Explanation: Again given the scale of the cosmos, there should be a sufficiently advanced civilization somewhere out there. Maybe we are still out of their reach. But with our current technology, their expansion should be visible even if it’s in a tiny part of the “observable universe”. That begs us the same question again, “Where are they?”
So what responses did other scientists have regarding this paradox? Here are some theories directed at solving the paradox:
Rare Earth Theory:
This theory simply states that getting Earth-like conditions is much rarer than we think it should be. Yes, an exoplanet might be in the Goldilocks Zone of a star system. But that doesn’t guarantee whether substances essential for life have been produced yet or might even be possible in the future. Or there might be extraterrestrial lives out there but there has yet to be significant developments to become intelligent. Maybe the sequence of events on Earth were actually more impressive than we think. Maybe we actually shouldn’t take our life for granted. The possibilities are endless, but the main theme is that Earth was a “miracle”.
Great Filter:
To truly be an intergalactic civilization might actually be a daunting and truly remarkable accomplishment. This theory might be the most reasonable of all; as we have already seen with the history of Earth that extinction events are more common than all. From biological fallouts (pandemics) to large scale meteorological disasters (volcanic eruptions, ice age etc.) to foreign object interventions (read asteroid impact events), almost everything has happened in the 4.5 billion years of Earth’s history. There have been 5 major events of extinctions in which almost the whole population of Earth was erased. Even we human civilizations came close to extinctions at major pandemic periods like Black Death, Plague of Justinian, Spanish Flu etc. or wars like World War 2, Cold War etc.
And the future for humans becoming a truly interstellar let alone intergalactic civilization might not be as smooth as we think; and the future is more bleak than ever with the ongoing wars and climate change situation hence , day by day, becoming the onset of the 6th major extinction event. Thus, the summary is that intelligent extraterrestrial life is common but it is highly unlikely that any two civilizations might make contact because of the menacing “Great Filter”.
Zoo Hypothesis:
Now, imagine that extraterrestrial civilizations are keeping themselves hidden from us knowingly intentionally and the reason is quite optimistic. The “grand” civilizations (technologically advanced to a point which we will take millenia to reach) are keeping an eye out on us, but they won’t intervene in our worldly affairs. Once we can overcome the “Great Filter”, they might contact us because by then we will become more mature technologically and socio-economically. Our psychology will be much different than today’s imperialist mindset and we might seek out for true universal peace. And finally they might start doing treatise with us as we won’t be hostile anymore. This is the brightest and radiant of all the theories out there. But the theory might break down if there is no homogeneity within the culture of the civilizations, or even the smallest fraction of a civilization turns rogue it will be a disaster. Which leads to our next and final theory.
Dark Forest Theory:
This is the complete opposite of the last theory. This time, imagine yourself walking through a forest at the dead of night when the apex predators are awake observing every step of yours and are ready to jump on you at any wrong step. Such is what the Dark Forest theory suggests that intelligent species are predatorial by nature. They work on their imperial tendencies of conquest and colonization. And any civilization equal or less developed than them is equal to death penalty for the other civilization. Hence, every intelligent species goes by the principle of “Shoot first, question later”.
The civilizations go through the insecurity and paranoia of what if every other civilizations are “hostile” to them. This can be considered as a darker sub-theory under the “Great Silence” theory as to why we still are not able to find any sign of extraterrestrial life, why silence might be the better option for us. As said by one of the greatest scientists of the modern physics era Stephen Hawking : “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.”
Given all the circumstances, it is safe to say that we will not be meeting with any intelligent species within this century. But before our first contact we have to unite ourselves first as division among human civilization might become the fall of our civilization and might never make it past the breaking point for advanced civilizations. And for truly becoming an intergalactic civilization we have to think about the peace of the universe instead of putting our hedonistic tendencies on top of all. For now we can assume, existence or extinction or the apparent devoid of alien life, all of the scenarios are scary for us.
written by Martin Fernando Pramanik
Advanced Civilisations Outside the Milky Way Galaxy?
