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.

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

  1. You’re assumption that a filter being ahead of us would mean certain death is incorrect. If a filter behind us means that it could be passed, the same would apply to a filter ahead of us. It wouldn’t be called a filter if it allowed nothing through, it would be called a wall.

  2. humans won't last forever, all these theories just can't get over that, nothing last forever humanity will die out one day it's not a bad thing it's natural, something else will take its place

  3. Step 1 : Wait for humanity to advance for another 30 000 years.

    Step 2 : Unite the entire planet

    Step 3 : Build spaceship factories on mars

    Step 4 : Colonize the entire galaxy

    Step 5 : Humanity fell into a civil war

    Step 6 : Fall into an age of regression and ignorance for the next 10 000 years

    Sounds like fun

  4. I see an error…
    If you look at every earth-like planet past the closest one to us, they're all beyond 1000 light years away. That means you're seeing the planet as it was 1000+ years ago, since however many light years away it is is how long it takes for the light to reach us, which means that, if they evolved at the same rate we did, they probably don't have the possibility of making enough light to be able to be seen from space, which is why we can't see it.

  5. I believe it much more likely we are simply too far away from intellegent life to actually be able to detect them. The conditions necessary might simply be very spread out. The great filter happened before and very little life is left and is simply coming back. Future smaller filters may exist in our future still.

  6. I still dont understand why the presence of alien life means it is bad because the filter is ahead of us.

    If we discover ancient alien ruins on Mars we can actually learn from their mistakes and find solution to beat or prevent the filter from happening.
    if we discover a lot of intelligent civilization then the Fermi Paradox is not a paradox anymore

  7. Couldn't it also be that another civilization(s) is only marginally ahead of us or even behind us in the larger universal time frame?

  8. What IFFFF aliens are able to hide themselves..their technology wouldve be more advanced IF they r steps ahead of humans on the staircase

  9. Perhaps a creature like us, a "humanoid" as one might call it, is the pinnacle of what the universe "in itself" can biomorph into being in a very long time span.

    Perhaps the beings we would call real extraterrestrials are nothing like that. Comparing them to us might actually be stupid but something our "biomorphed and stupid" thought functions compell us to do.

    Extraterrestrials might even see us as disgusting "biogrowths" that miraculously have somewhat complex nerve network that resembles thinking 😉

    Think of an old rotten food that tries to climb out of the garbage bin.

    A nice contrast to popular theories… Try not to take this in a negative way.

  10. it could also be that we are being observed and they're just waiting to see if we're gonna end up being a threat or not. and simply wait and see until then.

  11. The problem with this is that humans right now cannot see millions of years into the future to even know what advancements will be made or how they might affect us. Perhaps the aliens are not dead, but moved on or moved in (VR)…

  12. The Goldilocks zone theory assumes that all life is carbon based like on earth, because we have no other reference yet. There might still be life as we do not know it out there. They could even be arsenic based life forms for all we know, so the Goldilocks zone doesn't have to be a criteria. we know so little and it's naive and shortsighted to pretend otherwise

    Stephen Hawking once said a meeting with aliens would lead to our doom, because that's how the Spanish treated the natives when Columbus "rediscovered" America. But that presumes that They are like us, and is based on HUMAN history. Maybe the key to advance to interstellar migration is to stop fighting each other over this tiny speck called earth, and respect all living things, and work together instead of dominating and competing?

  13. Maybe the filter is something akin to Mass Effect's reapers, some kind of being which observes the Galaxy, and the instant it detects life, it attacks, eradicating those life-forms.

  14. So, there is a great filter that completely obliterates any lifeform that becomes sufficiently intelligent.

    My God, Mass Effect was right, the Reapers are real.

  15. This is such a narrow idea. the vast randomness of the universe and life can't be so easily explained black and white like this.

  16. what galactic civilization lol we can't even live peasfuly with each other on earth.. we dare t imagine a galactic civilization and we are wandering why it hasn't happened yet? lol it's better like that so that the universe won't get destroyed

  17. scenario 3: we are not good enough almost all the time killing each other and distroying our planet so the universe doesn't let us go on.. but we are too selfish t admit that… also the fact that we are aggressive doesn't mean alians are too.. Just cause we are diffective we can't imagine others better than us

  18. Or the actual filter is actually God, and it destroys a civilization if it becomes powerful enough to start infesting other planets than the one it was originally placed.

  19. Isn't this theory a huge logical fallacy? It seems to present two scenarios: (a) the great filter is behind us; (b) the great filter is in front of us. As if they are the only possible two scenarios! The fact that we have no clue whether (a) or (b) is true, or what this 'great filter' might be, indicates that there are probably also scenarios (c), (d), (e), and so on. In our ignorance, we just don't know or haven't conceived of them yet. Relax, people! But this is still a great video, because it presents a difficult scientific concept in a digestible form.

  20. Maybe we are just not developt enough to be worthy to be contacted. If they are aliens out there maybe they're just not interested in making the t contact. Also, our tools are still pretty cruel to explore the galaxy and our knowledge is so little about space. Heck, we don't even understand dark matter and that's all around us. I'm sure somebody is out there exploring the galaxy. I can't prove it but you can't prove that there isn't. It's just like faith.

  21. OOOOORRRR life is SO common that there are lots of planets with tech robots on it already, colonizing other nearby planets

  22. Black hole: starts Shining and science can't explain why
    South pole: melting and probably about to release a primitive virus
    Weird noises at my garage: exists
    Me: Aww yeah, it's all coming together

  23. our great filter : realizing that we have become a huge burden on this planet and that overpopulation is an alarming problem and starting to act towards it without regards to emotions, something which probably will never happen and will lead to our extinction and most likely take with us all of life on this planet, probably the only life in this entire galaxy

  24. lol dont tell me that you dont know… The great filter are te reapers
    its only a matter of time untill we discover the mass relays and the citadel, and from there starts the countdown to their return

    P.S. I am commander Sephard, and this is my favourite channel on the youtube

  25. 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.

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

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