Future of Humans
The Great Filter Theory: Are we alone in this Universe?
Are we on the “seen” list on alien iMessage?
Looking at the sky, I have always wondered is there anyone else, looking at our sun and thinking the same thing I think? One look at a cloudless night sky and you’ll see countless stars, some bright, some dim, all using the same physics. The stars that you see are not even a fraction of the number of stars in the observable universe. It is estimated that there are 1 billion trillion stars in the observable universe. The number is just absurdly large.
So why are we along in this infinitely vast universe with billions of planets that are earth-like? Why is it when we look at the sky, we see a static, uniform universe with no fluctuations that can indicate the evidence of life. This is a question that many scientists and philosophers have asked. Today, we look at the possible answers.
The possibility of life
Earth is a planet. It is a special planet for us because it is the only home we have. But is it really special? Since it harbors life, it is safe to assume that earth is special. But let’s look at some possibilities. How many planets are there in the universe? And how many planets are like Earth?
Looking at the number of planets in the universe would be stupid since we haven’t discovered all of them yet, but we can estimate the number of our galaxy. Milky Way has around 400 billion stars in which there are about 20 billion stars. 4 billion of these stars have a planet that resembles earth. They are in the Goldilocks zone (right temperature).
So if 0.1% of these planets have life, that’s 4 million planets with some form of life, capable of changing the atmospheric makeup of their planets. But of all the planets that the Kepler Telescope and the Sloan Digital Sky Survey has analyzed, none showed any signs of life. Why is that? Since the universe is unimaginably large, one would expect that however rare life is, there will be one planet with some kind of life in it. Yet there is no one out there. This is the Fermi paradox, named after Enrico Fermi.
It isn’t that we cannot detect changes since the universe is too large and out technologies are too primitive (relatively). We have seen the Trappist star system has very favorable conditions to harbor life. But we haven’t detected any signs of life. We also detected certain light anomalies coming from Tabby’s star. Everyone thought there was some alien megastructure around the star but sadly, it was just a dust cloud. This “Great silence” in the universe can be explained in terms of the Great filter theory.
The Great Filter
The idea of the Great Filter is there is a barrier that life must cross to survive. There is no specified number of barriers that we know of, but since we are surviving and we know our evolution and the history of Earth, we can formulate some barriers.
- The Right star system
- Reproductive organic molecule
- Simple prokaryotic single-celled life
- Complex eukaryotic life
- Sexual reproduction for gamete transfer
- Multi-cellular life
- Animals with an increased brain capacity
- Humans
- Colonizing explosion
The 8 filters have been crossed by life on earth, and we are currently on the 9th stage, waiting for technology to take us to different planets and possibly colonize them. Mars is first on the list. To understand how these points are filters, imagine we ruin our planet (or something goes wrong) and all of humanity dies. This does not necessarily mean all life will die, but if bacteria survive, evolution has to start again to cross all the 8 filters to reach where we are today.
The Takeaway
There may be many planets with life past the third or fourth filter, but a catastrophic asteroid could strike and end/restart the whole process. This could take billions of years. Maybe we haven’t waited long enough to look for life. Perhaps there are millions of planets with small, single-celled life forms evolving slowly. Or perhaps life is being created and destroyed multiple times in multiple planets and Earth just got lucky. Life on earth took billions of years to cross the filters. Researchers found hematite tubes that resemble tubes built by bacteria in deep-sea hydrothermal vents which were 4 billion years ago (Dodd et al 2017, Nature 543).
Maybe we are not worth contacting?
The closest animal that resembles humans is chimpanzees and bonobos. The DNA of humans and chimps are ~96% similar. So the difference of just 3 to 4% gives humans the ability to solve differential equations, understand black holes, drink coffee, and millions of other things.
What if some other life form has evolved billions of years before us and is 4% different from humans just like humans are different from chimps? And why 4%, how about 30%? They’ll be Gods to us, perhaps controlling the universe in which we live in.
Sending radio signals out in the cosmos is stupid for two reasons. First, light is slow when the size of the universe is taken into account. Radio signals started propagating out of Earth when TV broadcasts started. So radio signals have just reached about 70 light-years. The Milky Way galaxy is some hundred thousand light-years across. If there is a planet with advanced life, say 500 light-years away, the radio signals still have 430 years more to go.
The second reason this is stupid is radio signals are primitive. An advanced civilization may have stopped using radio signals altogether. Like using gears and levers to make a spacecraft. This is why they have not contacted us. We are primitive, with nothing interesting to offer. They just leave us on seen. Or maybe they are all dead.
More filters ahead.
The 9 filters that we have hypothesized from our past are not definitive. Maybe there are a lot of filters and many other life forms have failed to pass it and died out, leaving no trace at all. What could be the possible filters? Let’s hypothesize.
The technological filter is when we become so technologically advanced that we become a threat to ourselves. Maybe, like nuclear war, people develop some destructive weapons and they start squabbling over petty issues, resulting in at the end of the world. If you think it is unlikely, remember how long Cold War lasted?
It could even be unintentional destruction brought by technology. Maybe creating an Artificial intelligence that kills all organic life? Or maybe trying to cure disease while creating some adverse effect that renders all of us dead? Technology is a double-edged sword and a small mistake can cause large destruction.
Conflict with other species? What if when life gets too advanced, they are visited by some other advanced species that are competing for the same resources. What results is an intergalactic war between the two species resulting at the end of both. It is a possibility, however, it fits more like the plot of a sci-fi story.
Maybe we are meant to leave this universe? What if this universe is like the womb and humans are merely the fetuses? What if the universe we live in is just an incubator, preparing us, giving us resources to go out in the real universe? Other species that survive these filters move on to the next universe? Highly unlikely, but a possibility.
Why filters are true.
The term filter makes us think about the paper filter that we use. But look at the bigger picture here and you’ll realize that filters are everywhere. They just have different names. Each day, humans filter so many thoughts, decisions, etc. The ones exist if they pass the filters. The ones that don’t pass, die out.
Not just humans, but natural selection is also a filter, evolution being the process of filtering. Lifeforms with abilities to survive the environment live while others die. An organism with gills will survive if the world is flooded. Here, gills are what makes the organism pass the filter. Maybe intelligence is our gills in a flooded universe. We need intelligence to pass through one filter. But we may need something else to pass through another.
Maybe fusing with artificial intelligence can allow us to pass through other filters. If we need to pass through the filter, we must adapt or evolve. This brings us to the Kardashev scale which measures how advanced civilization is. Scale one on the Kardashev scale is the civilization that can manage resources of the planets. More efficient, higher they are on the scale. We are currently at 1.6. Once we start controlling storms and weather, we’ll be on 2. A civilization 5 can move a galaxy at their will. Maybe life reaches a point where it does not want to live in this universe?
The Matrioshka brain
The concept of a Matrioshka brain was first proposed by Robert J. Bradbury in 1999. The concept says that with enough computing power, humans can create a simulated universe where we can upload our consciousness and do whatever they want. The computer would be the size of a planet, like Mars.
So what if we are living in a universe that has even created by someone else? What if it is a simulated universe because the real universe out there is so ugly or hostile that the advanced life chose to live digitally. There is no way anyone can oppose that we are living in a simulation and people like Nick Bostrom have advocated the idea of living in a simulated universe.
Perhaps that is what life is. Maybe we shall never know if there is any other filter or not. And if there is a filter and we reach it in our lifetime, we shall know it. But we won’t be here to tell the story about it, or us.
References:
Nick Bostrom’s simulation theory
Great Filter Theory answering the Great Silence
