Why Alien Life Would be our Doom – The Great Filter

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.


  • Kurzgesagt – In a Nutshell says:

    There's brand new stuff in the Kurzgesagt Merch Shop. Check it out here: shop.kurzgesagt.org

  • Herbstlaub says:

    With a sample size of one population, imagining a "filter" is speculative. If we would find another civilization it would say nothing. However, there are plenty of plausible reasons why we would not recognize another civilization existing in the universe.

  • Penguin Boi says:

    This video: exists
    Me: X doubt

  • Xion says:

    1:38 planets do not have a limited lifespan and carrying capacity. Like adding a new room to a house or the advent of a mobile home a planet can be upgraded to accommodate more people and even be mechanized thru science to become mobile. Incredible science would be needed and the mining of additional materials from other objects in space but it could be done. If you think it's farfetched you go back to the start of man and the evidence you have is telling them we sent a vehicle with people in it to the moon and back, and see how crazy they'll think you are.
    In another 100-1000 years technology will be incredible if that is we don't blow are selves back to the stone age with nukes.

  • Shane Lewis says:

    Okay that ending got me

  • Marmda Sun says:

    Why does life have to be built on water and oxygen?

  • RightReverend BubbaBullfrog says:

    Funny how this clip is WAY more satisfying as sci-fi than current Dr. Who.

  • Gabe Newell says:

    What if aliens are stupid and we are mor einteligent than them?

  • Josua D says:

    any chance that the great filter MAY be in our back, and in front of us?

  • Kirk Powers says:

    This vid makes me almost as depressed as Interstellar (the ending didn't help).

  • AndrewTehThug 100 says:

    We already have aliens. Bacteria and cells

  • Ashliyahnah Taylor says:

    How can we spread to other planets when we haven’t even roamed 90% of the ocean. We only know 10% of it

  • Live freely and Wonderfully in joy. says:

    The narrator siad life began when dead chemisty decided to become alive that was not an wise move tho😂

  • Zafoshin says:

    a bit paradoxical that discovering life is bad, because we haven't discovered enough life. At some point the straws of hay become a stack and it would be actually good. At least in the context described in the video, because good and bad are relative terms.

  • Toxic_gaming says:

    the death star

  • Bird Up says:

    You know, this is a really serious video and all people can do is make memes out of it.

  • Rahul McDan says:

    What is your personal "driving force" to live, work and struggle, if you know that someday in the future, life and everything we accomplished will cease to exist and sink into oblivion? (Sun engulf Earth, Heat Death, Big Rip, colliding pocket universes, possible proton decay, death by black holes, etc) Thank you in advance.

  • shsjababzhjs alakowhsbzbhah says:


  • Lefty Luchiano says:

    7:31 Ayy lmao

  • Fred TES3e says:

    5:54 What the Reapers? That's too depressing…

  • Rose Marie Adoracion says:

    This is my idea we will runout of air

  • DIY MAN says:

    Or we could be simply be created by God and this whole space thing is completely pointless since we are the only ones. Because so far for life out side of earth the score is Bible 1 vs science 0

    And i just started comments war.

  • Unknown Soldier says:

    Knowing women they probably start having "relationships" with the aliens and claim love is love.

  • Alaris Poljanac says:

    I believe the filter is ahead of us.

  • Donavon Ho says:

    I prefer the way stephen hawking put it.

    life is so improbable and the universe's history and size so expansive that human civilization is just a blip in time. There may have been other civilizations in our discernable universe, we just missed them, and those that come after us may miss us too.

  • Max Long says:

    Why bother even looking for aliens?

  • solid says:

    0:11 you forgot area 51

  • Bryson Kinnan says:

    Everybody always says the mitochondria is the “powerhouse of the cell”, but nobody really knows what that means. Great video, by the way. One of my favorite kurzgesagt ones

  • Pluto x says:

    This intro sounds like peppa pig 🐽

  • Pluto x says:

    Big brain

  • Paul Backer says:

    I think the filter is behind us. I'm saying this as it took a great deal of steps to get to where we are at and a great many of those are flat out not available on a great deal of other planets. Things such as the water/land ratio needing to be around what it is here on Earth to promote complex thinking to the point of making tools but wet enough to support complex life to the oxygen/temperature needed to promote a fire…and with that, a way to not only make a natural fire, but the tools that can be made with using it as a building block as well as the complex thinking to not only use fire, but to be able to make it.

    To add with the fire, their is a complex civilization, farming with plants and animals to support the resources for others to be able to advance complex thinking. With that, the need for laws and protecting others instead of a flat out "Survival of the Strongest, but Stupid" system of laws. And with that, to have laws and with those laws, a common plan to move beyond the 'now'.

    Then from there, the time needed to develop all of these tools as well as the educational system to be able to teach each of these to the next set while avoiding all of the natural disasters such as Supernova, Gamma Ray Burst from afar, asteroid strikes and so on with events outside of the creatures control for not just a few years, but centuries as well as millennium upon millennium of the lack of a catastrophic misfortune.

    I'm not even going into the idea of biology with this one as I don't have an hour to explain further but think about why we haven't seen a sperm whale making fire or a mouse to speak…much less, drive a car.

    Plus, the distance between just two stars is extremely and mindboggling complex. It takes the sun just eight minutes to shower us with sunlight, but the nearest star outside of our solar system is 3.8 years to be able to shine on us. That's minutes from our star, to years for the next star. And with that, we are decades from being able to even see our sun with our own eyes, up close and 'personal'.

    The odds of just these are astronomical to accomplish and this is just a rather short list of what is needed. The "Filter" is quite advanced. I do see the human civilization reaching out to help other species eventually as our 'human' nature is going from a warlike civilization to one that truly does wish to help nature as a whole. We aren't perfect on this ideology yet, but we came a very long way to achieving this within the last hundred years, image a thousand to yet another million years from now from where we are today.

    I truly think that we aren't the first in the universe to do this, but with the gross amount of distance, technology required and with the astronomical speed limit to be achieved to even get close to the next star and with how many steps above it needed to even have the capability to not only think this, but to word it to others from not even within my area of the world…it is no shock, none whatsoever that we haven't seen complex life, outside of our own yet.

  • Off Monkey says:

    This is why we went to Area 51

  • Mikołaj says:

    I say we are the only ones, and life is extremely rare. If there will others nearby, we would already find signs of them.

  • Highmann Blaze says:

    The same craters on the moon and on mars start happening in Russia.

  • Dominic Bourque-Goodwin says:

    Feeling Doomed But Still Slightly Hopeful

  • Caligula Besniq says:

    i like the Adventure Time reference

  • Alex Helmin says:


  • Biednymaniek says:

    Its not relevant haw, Atoms hold his mass, so it must grade up to OO 🤔

  • Bad Connection says:

    I beleive we can do it. We just need to stop stuffing around become aware of our reality.

  • T Bradshaw says:

    But maybe the reason to us not finding other life is just because the universe is so vast it's like finding a needle in a hay stack at an exact point in time

  • Exodus Hybrid says:

    Maybe aliens saw are planet and just decided fuck that looks like a piece of shit. titan it is

  • Local Dingus says:

    that we could help each other through the great filter. We could both be intelligent enough to realize that the universe hates us and we could have each others backs.

  • a wild peridot says:

    is this the new infographic show

  • daecromancer says:

    my mind goes back to the wars of mass effect, and the big thing stopping evolution from going to far by wiping everyone out at once ……..

  • Harish Raju says:

    The last few minutes were beautiful

  • Goobert Froobert says:

    >:c I don't care if we go extinct, I want my goddamn alien friends right NOW. >>>:c

  • SaggyT Photography says:

    Or space is just too large to find other civilizations in time

  • Jose Madrid. says:

    Big brain!!!!

  • Ashton Giertz says:

    I'm pretty sure that, since the great filter is used as an explanation for why we aren't seeing any extraterrestrial life, finding intelligent life would just debunk the great filter theory. besides, we'd have to find evidence of areas that used to have life; ruins and such, to get any evidence that the great filter even exists.

  • Umer Warraich says:


  • Dominik ballard says:


  • Joe Playing Outdoors says:

    There is life out there. They have posted danger keep out signs all around us warning any intelligent life to steer clear, only morons here out to destroy themselves for a buck.

  • PointBlank200 says:

    Humans are their own enemy

  • sendercorp says:

    Sendercorp we bring peace, to the multiverse.

  • pejott says:

    I think it's more likely, that other lifeforms have decided to not intervene with us, because we need to get there by ourselves or something.

  • OAL sythe says:

    These videos give me existential thoughts

  • Rose Faith Angel says:

    Nasa are liars. No space travel. Jesus is coming again and we must stand up for our beliefs and the Bible now.

  • whynottalklikeapirat says:

    Well – maybe we are just among the first and there is no filter and many will follow …

  • iH8AttentionSeekersEvenThoIAm1 says:

    Wow that rocket looks a lot like a… mushroom

  • Spoohky says:

    There is a more intelligent civilization out there they just decide to ignore and not care about because how stupid we are compared to them, just as we do with animals on our planet that are stupid we ignore them n don’t try to teach them how to do things we can

  • Geørgie says:


  • Pietro Pietro says:

    What if actually we'd find other intelligent life forms and the key to overcome the filter is forming an alliance with them?

  • MATRIX DTA YT says:

    there coud be alot of scenarios i cud write this comment up to 100+ words and still woudnt finish why there coud and cuddnt be life in other planets

  • Roberto Morales says:

    Alien ruins on titan

    Was this your home?

    It was yo, and it was beautiful

  • Gucci Nova says:

    Yeah but there is no real fallible proof of evolution, nor one for the big bang theory. This whole video is bullshit.

  • swapertxking says:

    the saying goes, "either we are alone in the universe, or we are not, but possibilities are terrifying"

  • EoinMP says:

    Can you do some funny/joke videos?

  • Oliv Trees says:

    Or maybe the future wall is a good thing- like evolving into super happy invisible aliens. We might be surrounded by them.

  • Marcus Vipsanius Agrippa says:

    invalid logic. because we have not seen life doesnt mean it's not there. 2. we have checked less than 1% of stars/planets.

  • Sauna Mad Man says:

    What’s going on across the seas? It ain’t nothing just the aliens trying to take something!

  • Satevo says:

    If we're the only ones, it seems like an awful waste of space.

  • Yazid Mouhcine says:


  • Jay Speakman says:

    Interesting, but I disagree. Finding the ruins of an ancient civilization simply means that civilization, for whatever reason, didn't make it. It doesn't mean that would be the case on other planets.

  • SadLife says:

    "The first 688 people to use this link will get 20% off their annual membership."

    We were in the verge of greatness. We were this close.

  • joshua foo says:

    Perhaps the next filter is common world goal, progression in all beneficial fields.

  • Kirtan Chavda says:

    Which software are you using to create such an animated video?
    It's Amazing!

  • MotherNaturesMother says:

    my science teacher sounds like you and is smart as you what the hel

  • SATAN says:

    Naruto run thru the filter. Problem solved.

  • I Self Law Am Master! Arm leg leg arm head! says:

    200k years to get to the brain we have now is speculation. There is a great gap in evolution between homo-erectous and homo-sepian sepia. 200k years can only explain the first mining community or sophisticated civilization known discovered on this planet.

  • Christian Canon says:


  • cfehunter says:

    Surely the best outcome for us would be to encounter a benevolent species that's more advanced than us?

    That way they could tell us what the filter is and help us avoid it and potentially elevate our technology.

  • Refinedthought says:

    Ever heard of The Hereafter?
    Well thats the future.
    Good luck

  • parvx8 music says:

    Goldilocks zone holds life similar tu us…..
    What about life which isn't just proteins…??

  • kostas papakitsos says:

    Nah we just gonna die

  • Nathan Evans says:

    Kurzgesagt, are you some type of scientist with theorys or do you have a pal with all of this knowledge? Whatever it is keep up the good work!

  • Кирилл Шамиданов says:

    2:15 Corusaant!

  • Pronoob Entertainment says:

    Maybe the filter is climate change

  • Dr. Hanus says:

    “Mankind was born on Earth. It was never meant to die here.”

  • Jack Taylor says:

    Prokaryotic merging has happened at least twice, probably more. Chloroplasts & Mitichondria are the obvious examples, but there is also limited evidence surrounding the nature of the nucleous itself and that there may be more than one kind of Chloroplast.

  • Asianhacker says:

    we're in frnt of the filter

    it's us trashing our planet or global warming

  • JaidenThePoodleMoth722 says:

    I'm An Alien Living On Earth, This Offends Me.
    I Am Clean, I Used Earth Soap To Clean Myself.

  • James RC says:

    Colonise the universe

    Queen Victoria turns in her grave

  • Gavin Horn says:

    What if there is no filter

  • codragdus says:

    Wait. If we suddenly find all kinds of advanced civilizations, then why does that mean the filter is ahead of us? Maybe it just means there’s no filter.

    The premise that there is a filter is based upon our inability to detect other other civs, after all.

  • cOOkie m o n s t e r says:

    The scary thing about aliens is that aliens might be real but just in different galaxy’s and even smart people to are saying their are making portels to different dimensions which is scary cuz what if a dangerous creature from the other dimensions goes into the portel we made and reals distruction on our planet

  • Ori Adam says:

    What about a simpler explanation – that galactic travel is impossible?

  • Alex Leonhart says:

    What if humans decide to live on separate planets and start to evolve differently creating alien species.

  • Maccas Games says:

    I don't know what I would find more consoling… A universe made just for us, a universe created by random chance, or a universe not created, but simulated.

  • Me_ Potato says:

    1:17 bIg BRaIn

  • WORMY says:

    What if aliens were scared of us? We are using our technology so carelessly that maybe they think that we are stronger than them and are trying to lure them in, maybe… Just maybe…

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