The Fermi Paradox is a thought experiment coined by physicist Enrico Fermi, who once pondered that if the conditions of life are common enough for there to be intelligent life in the universe, “where is everybody?” And this in turn is based on an idea called the Drake Equation.
The Drake Equation is a bit of speculative math that calculates the number of civilizations in our galaxy that could communicate, with factors of the rate of star formation, the share of stars that have planets, the number of planets that could support life, etc. See Wikipedia for the whole thing: https://en.wikipedia.org/wiki/Drake_equation?wprov=sfti1#Equation
From the Drake Equation, and actually even before that particular formula was published, scientists estimated that because there are more than quadrillions of stars out there, there should be hundreds of millions of civilizations. And Fermi responded to this by asking, where is everyone?
There has been a lot of subsequent speculation on the “why” but I think that there are a lot of good answers out there. My favorite is simply the age of the universe.
Let’s go back a step: How did we get here? Specifically, what are the steps that it takes to get from the Big Bang to a person typing an article like this?
We know that life such as human life requires not just the basic organic elements, carbon, hydrogen, oxygen, nitrogen, and phosphorous, but also heavier elements like iron. And we have learned from astronomy that these elements did not form in the Big Bang itself or in regular stellar life. The main energy source of stars is simple fusion, the merging of hydrogen nuclei, simple protons mostly, into helium. But stars generally do not continue fusion past helium; instead, when a star converts all of its hydrogen to helium, it either just slows down and cools, or explodes. And it is this explosion that produces the heavier elements like carbon on up.
It takes a really long time for a star to form in the first place and enter its “sequence.” And then it can take billions of years for it to burn through its hydrogen supply and explode in the kind of supernova that produces heavy elements; and not all stars will explode in that way. But once they do, the result is often another star system forming, this time with planets composed of those heavy elements, and it is on those planets where life is most likely to form. Some of them, anyway.
The sun we all know and love is not the star that we came from. We actually came from a prior sun which we will never see an image of, a sun that exploded nearly halfway back in time from here to the Big Bang. After that star exploded, producing the heavier elements that make up most of our bodies (we are 70% water, but water is 80% oxygen by mass, meaning more than half of our mass is supernova stuff), it was a little while longer for the solar system to form, over 4 billion years ago. It took nearly a billion more years after that for life itself to start, around 3.5 billion years ago, and then probably another billion to get to eukaryotic cells.
We could get into another theory, the “great filter” hypothesis, which talks about eukaryosis as one of many filters. In our history, it seems to have taken around 1 billion years for this tremendous event in evolution to happen. Eukaryosis was the event of one single called organism merging with another to form the first complex cells. Cells in our own bodies for the most part could be thought of as compound cells, with cells within cells, biologically called “organelles.” The most well known of these are the cell nucleus, the actual DNA of the cell, contained inside its own inner membrane, and of course the mitochondrion, the “powerhouse of the cell.” Life existed without these things for a billion years and it’s impossible to say whether it actually needed that long, or if it was a “probabilistic” event that could have happened at any time and just randomly took that long. But it did take that long, and it took as long as it took after that to get to us.
Could it have gone faster? Perhaps. But so many things were happening along the way that inherently go slowly, things like the cooling of the planet from a hot primordial ball of elements heated by gravity and friction to something in the right temperature range to support primordial life. I like to think that we went along the process about as fast as we could, and recently we have been proceeding at a breakneck pace. We formed as a species only within the last hundred millennia or so, started building complex societies
less than 20,000 years ago, and started intentionally recording history less than half that long ago. Yet, we went from discovering electricity to creating metallic objects that can imitate speech and thought in under three centuries. We are now well within the cognitive era (not an official name) and science is proceeding into new theoretical knowledge and applied technologies faster than ever before. Yet travel beyond the inner solar system remains, for the moment, still beyond even realistic theoretical solutions.
So the hypothesis that I found most appealing to resolve the Fermi Paradox was this simple idea that we are just early to the party. Although one could imagine ways for life to get here faster than we did, perhaps by a billion years or more, most stars still aren’t old enough for us to expect life like us there. But in a billion years or more, that is likely to change.
We went from the formation of “warm blooded” animals to the space program in only around a hundred million years, a tenth of the time it took us to get the mitochondrion.
There could in fact be countless planets with primitive life out there, and indeed we hope to find them with the James Webb telescope. And then we could discover a large fraction of those bearing complex life that still falls way short of what we consider sapience; that is, the capacity for abstract thought. It could of course be the case that organisms get to complex abstract thought and never proceed onward to advanced technology simply because they don’t want to, but it could also be a matter of millions of years to get from there to an “impossible” innovation like interstellar travel, which may or may not ever prove possible.
But the Webb has already changed several terms of the Drake Equation.
When the formula was first articulated sixty years ago, several terms were thought to be very small fractions. fp for example, the fraction of stars with planets at all, went from almost zero to almost all, just in the past few decades. Similarly, ne, the average number of planets that can potentially support life per star that has planets, has gone up as we have learned that the “Goldilocks zone” is less specific than we thought even within our own system.
And so the expected result of the Drake Equation goes up, because when two terms of a multiplication formula go up, the expected result goes up by the product of the two. In other words the Drake equation calculation has gone up by nearly an order of magnitude.
This is kind of exciting to me if only because of the perverse flavor of hope that it gives me. I often get very sad and anxious about the direction humanity is going. This isn’t really new as people have been saying that since writing began. Plato said such things , and started three millennia of such worrying. My grandparents worried about extermination through regular war, and my parents got to add the stronger threat of nuclear holocaust. Now we see climate change ravaging our ecosystem and relatively few humans willing to do anything about it. Our hope for survival seems to be diminishing, and there is so far limited hope for even a lifeboat. As I think of evolution itself, I fear that the cognitive era may come to an end if the people with the genes for intelligence continue to delete those genes through “movements” like “childfree.” Our species may move through evolution back away from sapience, and if we do whatever “spark” we carry now may go out.
Yet if that does happen, I take consolation from knowing that we are early in the life of the universe. Second chances may not exist for humanity itself, but for the galaxy, absolutely. When the sun reaches its next stage of life and becomes too hot for Earth to survive, advanced life may evolve again on the outer planets or their moons. And somewhere, countless somewhere, eukaryosis is happening today and on perhaps fewer but still countless planets, cognition is happening. And soon the spark of intelligent life will indeed be everywhere, maybe in a billion years, maybe in a hundred billion, but we expect the universe to last quadrillions of years, with broad consensus that stars will keep forming for at least another trillion. https://en.wikipedia.org/wiki/Graphical_timeline_from_Big_Bang_to_Heat_Death?wprov=sfti1
That means that we are less than 1% into the era of the life of the universe in which new life can form.
We are just getting started.
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