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 thoughts on “Why Alien Life Would be our Doom – The Great Filter

  1. There is nothing terrible in this. We already know the universe will lose all of its heat and die. We already know we will all die. A great filter ahead of us could very well mean that expanding outside a solar system is completely unfeasible and/or a post technological civilisation is going to be pretty simple and bound to a small territory while being incredible immune to danger.

  2. What if the great filter is the ability for a civilisation to be smart enough to work together and not exploit its planets resources?

  3. IDK why, but people always assume that all existences' ultimate goals are longer life, reproduction and expansion.

  4. Bold claims about Milky Way planets and nothing to back it up on …. Or did you check those 100 billion planets? Just love when ignorant people make science videos to youtube that contain mistakes that are spotted by 7 year olds 😀

  5. This is what I learned from a sci fi novel, these rules are called the Dark Forest Rules

    1. Survival is the key of a civilization
    2. Civilizations need to expand
    3. When two civilizations meet, they don’t know whether each other will attack or befriend
    4. The risk of attack is more likely because civilizations wished to expand, and finding a planet that can provide life is good news because it means that planet can be colonized
    5. because of the risk of being discovered and attacked when meeting another civilization that is more advanced, civilizations must not risk being found or discovered
    6. Therefore, civilizations are hiding, and the earth not advanced to understand the universal laws above

  6. Maybe by the time you're smart enough to colonize space, you're also wise enough to realize it's not worth it.

  7. Perhaps the great filter, if it exists, is behind us, but we're not the only lifeforms to pass said filter. It could simply be that the nearest species to get past it is too far away for us to detect at this time.

  8. I still don't understand why aliens would need water to survive, where does that come from? Maybe they need some different source than us that is not water.

  9. Or an advanced civilization from ages past ended up creating such inteligent machines that they were wiped out. Now, those machines lay dormant and hidden waiting for the next cycle to come to an end.

  10. This video makes a lot of assumptions about the potential lifeforms being a bit too similar to us considering they would have evolved entirely outside of how our life evolved. What's to say that our process to become multi-cellular beings isn't completely foreign to how it is accomplished on other planets for instance?
    "it's in the nature of life as we know it to reach out" Yeah, emphasis on "as we know it" and the whole "it's very likely that this is a universal principal for civilizations no matter where they're from" but is it a fact? No. Not every human civilization was like Britain stealing everybody else's islands and I imagine alien life would similarly have this variety. You mention that big brains might be rare because they can be useless to survive and they take up too much energy. Maybe the very way that our life spreads is similar and Earth did it the hard/inconvenient way in this instance too.
    What I'm trying to say is that the very nature of how our life thrives could be well, alien, to how the potential other lifeforms are. Our ability to see into space is so very limited that it wouldn't be too hard for another advanced species to hide from us and while it makes logical sense to Earth life to spread to be as big and all encompassing as it possibly can, that might not be true for others. We evolved to be competitive, but I don't think that's inherent to all potential life.
    I think another very probable theory is that we are being actively prevented from finding other life. There might be a species so far advanced beyond us that we can't see them intentionally making it appear to us that the filter is there in order to isolate us from other life. Why? Who knows. We could be a laughing stock to a race of beings made out of a type of matter we can't even detect yet.
    Wanting to feel like we are special is a very human trait. That we're either the first to get where we are or we're the only ones to make it through. Maybe we just don't have the means to search far enough yet?

  11. Aliens are humans but from the future. If they kill us, their past is destroyed and their existence is warped. They know better than to charge a full on attack, because they have no idea what weapons we possess. They have seen what we have done to earth and now they are scared of us.

  12. I fear that the horrible truth is that it really only takes a few million years for a dead intelligent civilization to have its presence erased by time.

    Structures on the surface most likely collapse, decay, and erode into nothing in time. Structure in space may drift off or deorbit in such time periods as well.

    To find ruins to gauge how close we are to the filter may not be so reliable. There could be no ruins, or almost every world we see as habitable could've have a civilization like ours, only to leave no obvious trace.

  13. We're in the middle of the great filter. 6:53 says it all. We're depleting and fighting over resources, we're starting runaway chain reactions in the climate. It's highly probably that every intelligent civilization gets to these problems. If we don't solve the climate problem VERY SOON, we're on the best way to make the planet uninhabitable. And the bad news is, we're not even remotely close to solving the climate problem. Say hi to the great filter! It's coming very soon, you and me might see it live in action.

  14. Why would it mean our destruction to find other highly intelligent lifeforms? Wouldn't thay suggest that they too overcame the barrier, if there was such a thing?

  15. Hi i am a high position science student these videos can help everyone depends on their interest on what they want to learn please upload more videos (only if can do) to give more knowlege or to develop the learning of science to students i also learned many things in these videos keep up!

  16. I think that we are aliens that came from space or heaven because why are we the lucky ones with life on this planet i think we took this planet and that war was the one that made us forgot who we are and this happen twice with another human type species that we fought and why do you think that we are the last humans species on earth just homo sapiens and not the other ones

  17. Yes we started from a soup of dead cells????? Okay!!!!!!!! Ha ha (cough) Hhhhaaaaaaaa.. dead cells rearranging themselves in stable and resilient strains?? Really I did hear and read the captions correct?right?
    Just wow dead cells rearranging themselves, they are dead!!! They can't rearrange anything..you do know what dead means right?
    ………dead…haaa!…cells…(laughs inwardly)…idgits….

  18. I'm supposed to suspend reality and believe that intelligent and conscious life forms emerged from unintelligent nothingness, gradually making engaging in decision-making (unknowingly) to become better, stronger, and more complex. I'm supposed to believe that humans and other life forms used logic that we created during our evolution to program ourselves with code so complex that we still do not fully understand ourselves or the world around us. There is no design or program without an engineer. I do not subscribe to religion, but I am also not naive enough to believe that intricately designed and complex creations create themselves.

    Oh and then I'm supposed to believe that simply because we cannot detect other intelligent life, it doesn't exist. Nevermind the limitations of our technology to detect life in other far-reaching parts of the universe. Yes, let's continue to allow the scientific and medical communities to do our thinking for us, disregarding any agendas they might have. Let's continue walking blindly into the future of gmo's, toxic cancer treatment, addictive prescription medication, air pollution, water pollution, factory farming, forest clearing practices because hey…they know what's best, right?

  19. okay but this logic is based on the theory that we ourselves evolved out of earth life. but what if we are ancestors of an alien civilisation, injected into earth’s DNA to produce a crossbreed that could survive here, and all that we’ve achieved is because we’ve adapted to do so on another planet? what would this say about the great filter? it would erase all logic in this video – maybe we realize we are the endproduct of colonization and destroying ourselves wouldn’t matter cuz we are destroying ourselves on other millions of planets at the same time… it would take away this goal of the human endeavour, to colonize the universe, cuz that goal would’ve been reached already

  20. If you really think about it we are aliens our selves I always wonder how did life on earth start here?! Obviously we were all in space once before earth came up, what if aliens are just waiting for a planet they can survive in?!

  21. What if there's intelligent life close to us but they feel that they would be interfering with our collective evolution if we observed them?

  22. At 3:07
    We aren't lucky
    God chooses that for us
    And if there's another civilization in universe,,, it will be only if God wants ☺️😊

    .
    .
    .
    Peace ❤️

  23. the filters are:
    we take more than we give back
    we have discrimination no equity
    we have superior complex
    we are selfish and greedy, it's all about monetary value

  24. Since we already have so many structures and evidence of our existence send out into space (satellites, space stations, ships but also artefacts like the disc with mathematical information about earth) it would be likely if there would have been millions of other life forms before us that we would have found something similar

  25. If the Great Filter exists it would definitely be behind us. If the great Filter was ahead of us then their would be other planetary species that we could observe. Personally I believe there is no filter, I think the monstrous size of the universe limits what we can and can not see. Even if human could travel at the speed of light we could really only travel 40ish light years in any direction. That isn't very far…

  26. If such filter exist how do you know that ALL civilizations agree with this? If Such thing existed how do you know that no one ever put an stop to it, and that the reason whe hadn't been contacted is because someone made it illegal in order to it never happen again?

  27. Technology destroys the earth before it allows us to leave it

    Could be global warming, AI, nuclear war, Kessler syndrome, ect.

  28. Maybe there is an intergalactic organization regulating how planetary systems can interact with others. Maybe one of their rules is not to interfere with less advanced civilizations. It is just as we don't interfere with those tribal people living in the Amazon.

  29. Maybe the contact or finding Aliens is the Great Filter and it depans from us, if We will Pass him or Not. Maybe We must destroy them or make Peace with them.

  30. Anyone else depressed that humans have achieved amazing things and if we could unite we can explore our galaxy and and beyond but we are stupid enough to only have wars with our own species

  31. Life can be quite varied and diverse. tbh, the sea needs to be better explored and the earthen layers fully addressed before we move on to space imo.

    If we can't even build & have bodies that adapt properly under a high pressure sea atmosphere that's right next door, then humanity isn't ready for anything space has to offer.

    Terra-forming continents to better cover the expansive ocean? Pfft. Not even on anyone's agenda.

    If humanity can't even bother to debunk communication barriers & promote higher intelligence in other living beings (, species that don't fall under the homo sapient spectrum) on this shared planet, then humanity is far from ready to come into contact with other life forms.

    Humanity just seems like a spoiled obese pre-teen that not only needs to hit the gym, but also adapt a healthier mentality to treat others kinder than they do themselves.

    The internet is the only place that offers a united front that represents decent 'globalization', but the current governing countries and political systems are too slow to keep up.
    Even then, toxicity is abound among anything that relates to 'Political Correctness', Competitive E-Sports, and culture.
    Individuals rather argue points rather instead of respectfully discussing topics in order to reach a concrete conclusion free from bias.
    Truth, honesty, loyalties and virtue are all but fables in the common era to be spoken of akin to chivalry and etiquette.

    Humanity is does not meet the prerequisites.
    Humanity is not worthy.
    This is my fair and rightful judgement (and also my educated opinion.)

  32. 5:13 someone needs to look at the sumerian king lists, its background of what a char is and who the annunaki were and relics archrologists have uncovered, like that 400 million year old pickaxe which has wood that started turning into coal.. and other things

  33. Hey Kurzgesagt, I'm thinking something. What if this great filter doesn't have to necessarily "stop" civilizations. You said anyone would want to spread everywhere, but obviously the better places instead of the worse places are chosen, right? We're looking at quantum psychs, higher dimensions, etcetera. What if there's a better option that every highly advanced situation has chosen?

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