Why Alien Life Would be our Doom – The Great Filter


Imagine NASA announced today
that they found aliens. Bacteria on Mars, weird alien fish
in the oceans of Europa, and also ancient alien ruins on Titan. Wouldn’t that be great? Well, no. It would be horrible news, devastating even. It could mean that the end of humanity
is almost certain and that it might be coming soon. Why? Why would the most exciting
discovery of our lifetime be bad? Let us imagine the development of life, from its inception to us today, as a flight of stairs. The first step is dead chemistry
that needs to assemble itself into self-replicating patterns,
stable and resilient, but also able to change and evolve. The second step is for our early life to
become more complex, able to build more complicated structures, and use the available energy
much more efficiently. On the next step, these cells combine
to become multicellular beings, enabling unbelievable variety
and further complexity. The step above sees the species
evolve big brains, enabling the use of tools, culture
and shared knowledge, which creates even higher complexity. The species can now become the
dominant lifeform on its planet, and change it according to its needs. First shy attempts to leave its
planet are happening. This is where we are now. It’s in the nature of life as we know it to reach out, to cover every
niche it can. And since planets have a limited
carrying capacity and lifespan, if a species wants to survive, it will look for more places
to spread to. So the steps above the current
ones seem logical: colonize your own solar system, then spread further to reach
other stars, to the possible final step:
becoming a galaxy-wide civilization. It’s very likely that this is a universal
principle for civilizations, no matter where they’re from. If a species is competitive and driven
enough to take control over its planet, they’ll probably not stop there. We know that there are up to 500 billion
planets in the Milky Way, at least 10 billion Earth-like planets. Many have been around billions
of years longer than Earth. But we’re observing zero
galactic civilizations. We should be able to see something… …but there’s nothing. Space seems
to be empty and dead. This means something is preventing living
things from climbing the staircase, beyond the step we’re on right now. …Something that makes becoming
a galactic civilization extremely hard, maybe impossible. This is the Great Filter. …A challenge or danger so
hard to overcome, that it eliminates almost every
species that encounters it. There are two scenarios: One means we are incredibly
special and lucky, the other one means we are doomed
and practically already dead. It depends on where the filter
is on our staircase: behind, or ahead of us? Scenario 1: Scenario 1:
The filter is behind us. We are the first. If the filter is behind us, that means that one of the steps we passed is almost impossible to take. Which step could it be? Is life ITSELF extremely rare? It’s very hard to make predictions
about how likely it is for life to emerge from dead things. There is no consensus. Some scientists think it develops everywhere
where the conditions are right; others think that Earth might
be the ONLY living place in the universe. Another candidate is the step
of complex animal cells. A very specific thing happened
on this step, and as far as we know, it happened
exactly once. A primitive hunter cell
swallowed another cell, but instead of devouring it,
the two cells formed a union. The bigger cell provided shelter, took care of interacting with the
environment and providing resources, while the smaller one used its
new home and free stuff, to focus on providing a lot of extra
energy for its host. With the abundant energy, the host cell
could grow more than before and build new and expensive things
to improve itself, while the guest became the
powerhouse of the cell. These cells make up every
animal on the planet. Maybe there are billions of bacteria-covered planets in the Milky Way, but not a single one, apart from us, has achieved our level of complexity. …or intelligence. We humans feel very smart and
sophisticated with our crossword puzzles and romantic novels. But a big brain, is first and foremost, a very expensive evolutionary investment. They are fragile, they don’t help in a fistfight with a bear, they cost enormous amounts of energy, and despite them, it took modern humans, 200,000 years to get from sharp sticks
to civilization. Being smart does not mean you get
to win automatically. Maybe intelligence is just not so great, and we’re lucky that it worked out for us. Scenario 2: Scenario 2:
The filter is ahead of us. Plenty of others died already. A Great Filter before us is orders of magnitude more dangerous than anything we encountered so far. Even if a major disaster killed most of us or threw us back thousands of years, we would survive and recover. And if we can recover, even if it takes a million years, then it’s not a Great Filter, but just a roadblock to an eventual galactic civilization. On universal timescales, even millions of years are just the blink of an eye. If a Great Filter really lies before us, it has to be so dangerous, so purely devastating and powerful, that it has destroyed most, if not all, advanced civilizations in our galaxy over billions of years. A really daunting and depressing hypothesis is that once a species takes control over its planet, it’s already on the path to self-destruction. Technology is a good way to achieve that. It needs to be something that’s so obvious, that virtually everybody discovers it, and so dangerous, that its discovery leads almost universally to an existential disaster. A large-scale nuclear war, nanotechnology that gets out of control, genetic engineering of the perfect super bug, an experiment that lights the whole atmosphere on fire. It might be a super-intelligent AI that accidentally (or purposely) destroys its creators. Or things that we can’t even see coming right now. Or it’s way simpler: species competitive enough to take over their planet necessarily destroy it while competing with each other for resources. Maybe there are runaway chain reactions in every ecosystem that once set in motion, are not fixable. And so once a civilization is powerful enough to change the composition of its atmosphere, they make their planet uninhabitable 100% of the time. Let’s hope that that’s not the case. If the filter IS ahead of us, our odds are really bad. What we can hope for. THIS is why finding life beyond Earth would be horrible. The more common life is in the universe, and the more advanced and complex it is, the more likely it becomes that a filter is in front of us. Bacteria would be bad, small animals would be worse, intelligent life would be alarming. Ruins of ancient alien civilizations… would be horrible. The best case scenario for us right now is that Mars is sterile, that Europa’s oceans are devoid of life, and the vast arms of the Milky Way harbor only empty oceans hugging dead continents. …That there are billions of empty planets waiting to be discovered and to be filled up with life. Billions of new homes… waiting for us… to finally arrive. How likely is it that we’ll find life outside of Earth that is similar to us? Well, that depends on how many planets there are out there in their star’s Goldilocks Zone– the area around the star where water can be liquid. Because stars come in all sizes and configurations, this zone is different for every star system and requires a little bit of physics to figure out. If that sounds like fun to you, this quiz from Brilliant helps to break down the maths for exactly how this is calculated. Brilliant is a problem-solving website that teaches you to think like a scientist by guiding you through problems. They take concepts like these break them up, into bite-sized bits present clear thinking in each part, and then build back up to an interesting conclusion. If you visit brilliant.org/nutshell or click the link in the description, you can sign up for free and learn all kinds of things. And as a bonus for Kurzgesagt viewers, the first 688 people will also get 20% of their annual membership. And if you DO find life on other planets, it may be wise to leave them alone for a while.

100 Replies to “Why Alien Life Would be our Doom – The Great Filter

  1. energy abundance with no population regulation leading to massive population explosion and a demand for resources at a rate far greater than what the planet can replenish, possibly perpetuated by the less advanced members of the species who have gained access to said technology despite lacking the ability to create it themselves and thus, lacking the ability to understand the consequences behind its use.

  2. I wonder if our primal destructive behavior towards other living beings has something to do with the ressources' scarcerty and our fragility and also our need to extract the energy that maintains us alive from other living creatures?.. like what would it be like if we worked like plants, which basically only need water,air and sunlight to metabolize?.. then maybe our technological evolution wouldn't necessarily have to kill other lives on the way…

  3. i kinda just realized, i fear death in thinking im going to wait all this time to have another life, where i wont remember a thing and ill instantly be alive again after how ever long it takes

  4. If we'd discovered a more advanced civilization that ours, that wouldn't make any difference to us. Considering they're older than us and I took us millennia to find them, it's more likely that THEY have been monitoring us longer than we could imagine. Like… yesterday we knew nothing about aliens. Today we find out that they exist and might be a threat to our survival…so what is the point of panicking? Nothing has changed on the bigger picture, except we now know they're there.

  5. I had a thought – well more of a movie idea than anything, that way in the future we actually attain the peaceful, utopian world we've always dreamed of. after thousands or hundreds of years, man's instinct for violence has been forgotten. even any explicit records of wars or fighting have been buried somewhere or something. then of course we're invaded by a hostile alien species

  6. 6:43 on the note of AI, an AI destroying their host civilisation is not a great filter or solution to the Fermi paradox because the AI itself will still want to expand and we can still detect them.

  7. hmmm i don't agree with this. I will ponder this and maybe send to Skeptics Guide to the Universe and see if they see any fallacies.

  8. It seems you have come a ways since this posting, as it appears to directly contradict "The Egg". Seen from the perspective of that little gem, alien life would be inseparable from all other life, including us, and may simply be a life form more advanced than us in both a technological and spiritual sense which is egging us on, pun intended.
    A couple things I feel you missed in this film:
    ~We have certainly advanced in the way we treat one another, though we still have a long way to go. In the not too distant past, human rights, women's rights, laws against animal cruelty, laws against war crimes and the idea of countries forming an organization like the UN or The League of Nations would have been laughed at. There is no reason to think we would not continue to advance in these areas, or in ways currently unimaginable given a couple more millennia or so.
    ~It may well be that there is a barrier that will need to be crossed in our future that others may have already crossed. If we continue to become more and more efficient at killing one another, it may well be that there is a "barrier" in our not to distant future of learning to settle our differences non-violently that will have to be passed if we are to survive as a species.
    ~There is now ample evidence of something that has the appearance of being far superior to us technologically in our skies. This has been verified on a number of official fronts and also seems to have been with us in one form or another for a long time, perhaps as long as we've been here. And yet, there is no evidence of aggression, in fact, there is official records of us aggressing against UAP's where their response was evasion rather than retaliation.
    All in all, I believe you offered a thought provoking perspective in this film, but that it was a bit limited in scope and creative insight. However, I would say quite the opposite about your most recent work, The Egg. Not because it more closely aligns with my own point of view, though it does, but because it is better supported by the mystic branches of nearly every spiritual tradition, current understanding of quantum mechanics and the reports of a majority of experiencers of near death, psychedelics and NHI.
    Thanks for the great work!

  9. Just because you can't see life in other Galaxies does not mean it isn't there, including galactic civilizations. Other galaxies are millions of light years away, the only way we can see them is how they were millions of years ago, since information is limited by the speed of light. For all we know, the universe is seeded with life we can't see yet because the light they give off hasn't reached us, and won't for millions of years.

  10. The universe is enormous. It’s definitely very likely for other lifeforms to exist out there. If you think about it, it kinda sounds impossible for Earth to be the only planet with life. There’s probably billions of inhabitable planets with other beings living on it in the observable universe.

  11. So, there might be a filter we have passed, will run into, or, there is no filter and we are alone. That is kind of depressing in any case. Everything died, we are yet going to all die, or we are alone.

  12. What if we started on the other side and destroyed all our other places or planets and never learned to stop trying to make the same mistakes and we are doing again but this is the last planet ? So think about it and fix what you have. And stop the greener on the other side affect ?????????

  13. "Narrative" evolution crud. Should have seen THAT coming. BTW, the Catholic Church says they will baptize "aliens" but say that they are "…free from original sin…" y'all are just messing with people's minds, man. Interesting though! There is simply NO way that the "eye" or the "hearing" system in humans to simply "evolve". Derp-Deee-Derp!! Thanks! Hahahah! : ) -EB

    EDIT: EASY "FIX": STOP chasing RESOURCES!!! Period. SHARE them instead of a FEW people HOARDING them. Eh!?! Hmmmmmm!

  14. Might not just be a filter, could be evolutionary steps. Maybe all advanced civilisations discover multiverses they move into, or time travel, or maybe they evolve into energy, who knows? Maybe they all have Van Allen belts and moon landing really was a lie. Maybe it is impossible to go faster than light, and they happen to live quite far away, so we're still a few thousand years off from them detecting us and coming over. Maybe aliens are advanced enough to hide themselves, or have encloses us somehow to observe us before meeting. Great filter and all the other theories really just come down to guess work.

  15. I feel like this video goes under the assumption that humanity is static and not open to evolution, with the exponential advancement of technology, it’s likely we will soon reach the singularity, the point at which we fully understand our own consciousness and are able to artificially reproduce it, then we simply upload our own brains to non-living beings that can self propagate and boom, problem solved, we don’t need planets that can support humans anymore

  16. All the improbabilities in this video point us to one particular most probable explanation: life on Earth and the evolution of humankind was facilitated by a higher power. Our science in its current state is able to explain the mechanisms that exist to regulate this, but not to perceive the higher power or rule it out. Not being able to understand something doesn't mean it doesn't exist.

  17. Great video as usual, but not supporting the clickbait title here. "Why Alien Life Might Mean Our Doom" would have been much more accurate.

  18. Humans have passed one more great filter in 2009, that most people don't realize. Invention of a tool that incentives each individual to exist, work and get rewarded fairly. The tool is Bitcoin.

    Before we had no universal, and decentralized, fixed supply money. No we have. Human colony on moon doesn't need to invent it's own money or trade with gold bar.

    Even marsian civilization can use bitcoin for trade among themselves and with earthman. Although bitcoin Mining is not possible on mars

  19. I can guarantee that alien life will never be found. Ever. Humans will search for as long as they can only to continually fail.

  20. If we are able to create and live among complex AI then nothing will be impossible. Singularity is waiting for us. That's the only hope humans need to rely on.

  21. There's a lot of mistakes with the Fermi Paradox.

    First, it assumes life arising could have occurred since the beginning of time. Except, that's not the case. Let's assume abiogensis occurs only as we understand it to occur. This means it needs hydrogen (easy), Carbon (only easy after certain early stars went boom), and, critically, phosphates. See, Phosphates were not in abundance until the latest "round" of solar systems. This means that planets, such as ours, that would have the conditions necessary to give rise to life, as well as sufficient means to incubate life to the point that it could become what it is today, would not have existed for more than about 5 billion years. At about 4.5 billion years, this means that the Earth is only about .5 billion years off from being one of the earliest planets. It is estimated to have taken about a billion years after its formation for life on Earth to have arisen and another 3.5 billion years to go from simple forms of life to what we are today. If we are "normal", it means there is, really, only about a 1 billion year gap between when we came to exist and the earliest expectation of life similar to us coming to exist. A billion years sounds like a lot, right? I mean, we went from the Homo Sapien mutation to landing on the moon in about 0.01% of that time. For the purposes of evolution, it's a rather long time, yes. However, when you are looking at the vastness of space, it's nothing.

    There's the sheer vastness of time. We've been looking for alien signals for a few decades now but that's nothing. Let's say a species reached our level of development a million years ago. Do you think they would be blasting radio signals out for a million years, getting no responses back, in the hopes that some one will respond? There's the distortion of signals over vast distances. The odds of an alien species arbitrarily sending a signal towards us at the right moment in time and with enough concentration and a lack of interference is astronomically low. It's sheer vanity on our part to assume we are of such import that obviously aliens would waste so much effort in the hopes that we'll respond.

    There's also the simple desire to "explore" changes when you are looking at thousands of years of separation. Going "in" is as engaging as going "out" when you are looking at just a few centuries (dozens of generations) removed. People often conflate time to travel with the time to expand, but it's not. Traveling at 10% the speed of light, it would take 2 million years to cross our galaxy. Not think of that in 3 dimensions (kinda 2). The vastness is not something most people seem to be able to grasp adequately. Space is insanely big.

    Then there's the obvious difficulties in space. Space, unlike the movies indicate, is not a giant vacuum between planets. There are bodies larger than Earth out in the darkness. We already know this. Now, how many asteroids? Can you really zip out at 10% the speed of light for decades without colliding with something? Of course not. So, the reality is that expansion will be a slow creep. (The Expanse is a more realistic example of it).

    Fermi's paradox isn't a paradox so much as a failure to understand the complexities of space.

  22. How fucking depressing: "The best option is that we're alone in this Universe because we don't wanna know that there may be a Great Filter in front of us! Ah, and because we want ALL of the other planets for our own sorry asses". How boring, egoistical and egocentric. I can't believe that I just heard that. And this is a science channel?

    BTW, the Great Filter does exist and is indeed ahead of us, and it's blatantly obvious: the inmensity of space. Species that can get over it grows and form interplanetary, and maybe even interestellar civilizations, and those who don't becomes the ruins of single-planet civilizations (like humans, for example).

  23. We need more than hope, we have to do something about our demise if humans are as smart who they say they are. Stop taking so slow to learn before its to late!

  24. With the millions and billions of "beneficial" mutations it would require for all this "Macro" evolution to ever happen….
    You'd think we would have a few thousand observable testable proven ones by now.
    Not just a bunch of theories.
    Macro evolution is basically a religion more than a demonstrable science.

  25. Humans are attracted to simple explanations and scenarios. Why only one filter? Why not “n” filters?

    We made it only because several filters destroyed the more common life forms and allowed us to evolve and take over. So there are great filters behind us AND ahead of us.

  26. If some roadblock happens that sends us back before the industrial revolution I don't think we can recover. How would we restart the industrial revolution now that there's very little coal, oil and other fossil fuels left to power it? We'd permanently be stuck without enough resources to do anything.

  27. Why are we fulfilled at only being galactic species (: "our final stop: a galactic species")?
    We should and eventually need to go further. So why no intergalactic species? Yes reaching them is actually a problem, still theoretically unfixed. So maybe intergalactic isn't a good one since I don't see us reaching another galaxy while the galaxy and us are moving at near light speed away from each other… a universal species then? That could be quite fitting.

  28. This remember me of the Dwemers from The Elder Scrolls. Their search for advanced technology only lead them to their own destruction.

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