Great Filter Possibilities

Fudbucker

Philosopher
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A possible explanation for the Fermi Paradox (if aliens are out there, where are they?) is that there's something that kills off civilizations at X point, something that "filters" out advanced civs. One of the possibilities is that any civ making technological progress is going to eventually discover nuclear power, and if they have any concept of attack/defense, they're going to weaponize it, and when you weaponize nukes, you open a Pandora's Box, and most civs destroy themselves. That's one possible "Great Filter".

So what are some other possibilities? I posit that planets capable of supporting advanced life are very fragile, and when civs become advanced enough, they invariably disrupt the delicate balances of ecosystems and feedback loops, and quickly render their planet inhospitable for life.
 
Life finds a way to live in balance with its environment without having to destroy their solar system for parts.
Aliens, unlike humans, have realized that galactic colonization makes no sense, so they live happily ever after on their own world.
 
Life finds a way to live in balance with its environment without having to destroy their solar system for parts.
Aliens, unlike humans, have realized that galactic colonization makes no sense, so they live happily ever after on their own world.

If these hypothetical aliens can stabilize their birth-rate and stall their growth, no prob. But if they can't, it's going to get more crowded, and people will leave for other planets. And there aren't an infinite number of planets. And yet they're not here. So maybe alien civs have more control over reproduction than we do?
 
Distance explains the lack of contact, easily.

Even given distance, even given light speed limitations, a civ that can travel 10%C will have colonized the galaxy in a ridiculously short amount of time (in galactic terms). Earth would make a good colony planet, but there's no colony. So advanced civs don't colonize? Value indigineous life too much? Have already seeded the planet?
 
If these hypothetical aliens can stabilize their birth-rate and stall their growth, no prob. But if they can't, it's going to get more crowded, and people will leave for other planets. And there aren't an infinite number of planets. And yet they're not here. So maybe alien civs have more control over reproduction than we do?

Humanity doesn't have any issues with over-reproduction: we continue to increase global living standards even though total population is growing.
Urbanization means much more efficient use of food, water, energy and at the same time increases innovation and productivity.
There is no "peak" anything.
 
Someone is colonizing the galaxy. But on the other end, we won't know about it until 50000 years or so.

A civilization did arise near earth, but they all died out 1 million years ago.

The colonizers do not utilize the EM spectrum any more, the same way we are slowly abandoning it in favour of the internet.

There are several planets with intelligent life out there, but we happen to be the only ones with the compulsion to start exploring or a variation, we are the only (near) intelligent life that happens to be able to make tools AND fire. (Dolphins and octopi even if intelligent would not be able to fashion things)

Life is common, but intelligence is not, and we happen to be the only ones in this galaxy so far.

We are getting EM signals from a distant (long dead) civilization, but they have been so weakened due to distance and stellar interference our technology cannot detect them above background noise.

We are part of a really cruel reality program by some aliens who block all other contact.

etc etc etc.
 
Humanity doesn't have any issues with over-reproduction: we continue to increase global living standards even though total population is growing.
Urbanization means much more efficient use of food, water, energy and at the same time increases innovation and productivity.
There is no "peak" anything.

There are a finite amount of people that live on Earth. A growing population will eventually reach that number.
 
Even given distance, even given light speed limitations, a civ that can travel 10%C will have colonized the galaxy in a ridiculously short amount of time (in galactic terms). Earth would make a good colony planet, but there's no colony. So advanced civs don't colonize? Value indigineous life too much? Have already seeded the planet?

All these number are meaningless: space isn't like an ocean.

Any colonization effort would require massive sacrifices from the population of the Homeworld, but none of them will ever see any of the benefits of moving to another planet: distances make "trade" of any sort uneconomical compared to in-system mining etc.
So there will be no political will to pay for space colonization and no economic sense either.

The only possible scenario is to save your specie when it is in predictable peril. This wouldn't be the "extinction-level comet" because if you can build deep-space colony ships you can nudge an asteroid out of the way.
That leave your sun going super-nova.
In that case, a civilization will try to move to the next suitable planet, but not really beyond:
If there is a danger from other civilizations, then obviously your own colonies would be the greatest danger to you: they know where you are, they know your level of technology, and they know that you are a potential danger to them. Distance will quickly sever any ties that would make inter-specie war unthinkable.

So I simply see no scenario in which space colonization would benefit any specie.
 
There are a finite amount of people that live on Earth. A growing population will eventually reach that number.

nope.
for the year 0 AD, a billion people would have been unsustainable (the global population then was estimated at 170 million).

The projected 9.5 billion people in 2050 won't put undue burden on the world, given that growth continues to slow while technology is still accelerating: we are not anywhere near in terms of limits in energy, space, food etc. etc.

To guess that there will be a "too many people" scenario is a typical "if everything else stays the same" error in argumentation.
 
All these number are meaningless: space isn't like an ocean.

Any colonization effort would require massive sacrifices from the population


Why would you think that? Do you think establishing a colony on Mars would require "massive sacrifices"? I think we could fund it without the public sacrificing anything. And eventually, a Mars Colony will be self-sufficient.

of the Homeworld, but none of them will ever see any of the benefits of moving to another planet: distances make "trade" of any sort uneconomical compared to in-system mining etc.

Eventually, but not at first. Mars and Earth could trade easily. Earth and the next nearest colony could have long-distance trade, and by then new trade routes would start where new colonies pop up.
 
nope.
for the year 0 AD, a billion people would have been unsustainable (the global population then was estimated at 170 million).

The projected 9.5 billion people in 2050 won't put undue burden on the world, given that growth continues to slow while technology is still accelerating: we are not anywhere near in terms of limits in energy, space, food etc. etc.

To guess that there will be a "too many people" scenario is a typical "if everything else stays the same" error in argumentation.

Yes. A growing population will eventually deplete/overpopulate a finite planet's resources. I can show you with math, if you like, but I'm pretty sure there's an axiom, where X is a finite container/ecosystem, and Y is something that continues to grow at some positive rate: Y will eventually fill X.
 
Even given distance, even given light speed limitations, a civ that can travel 10%C will have colonized the galaxy in a ridiculously short amount of time (in galactic terms). Earth would make a good colony planet, but there's no colony. So advanced civs don't colonize? Value indigineous life too much? Have already seeded the planet?
Even if there were a bunch of alien space ships out there in the universe, what is the chance that they'd get here? There are a lot of places to go. Not to mention that the journey is pretty hazardous. As the years of a journey pile up, how likely is it that the journey will be smooth and safe?

Maybe the good people of Tralfamadore sent out a space ship a half million or so years ago, and just before it hove into view, a piece of space debris hit it and...poof...another one down. We'd never know.
 
Yes. A growing population will eventually deplete/overpopulate a finite planet's resources. I can show you with math, if you like, but I'm pretty sure there's an axiom, where X is a finite container/ecosystem, and Y is something that continues to grow at some positive rate: Y will eventually fill X.

but it's not, is it?

we get constant energy from the sun, and none of the materials we use are "lost". they can be recycled.
 
Yes. A growing population will eventually deplete/overpopulate a finite planet's resources. I can show you with math, if you like, but I'm pretty sure there's an axiom, where X is a finite container/ecosystem, and Y is something that continues to grow at some positive rate: Y will eventually fill X.

Not necessarily. Its not like most resources go anywhere. By limiting population and recycling you can sustain things indefinitely. After all, the power source of the sun can power everything we'd ever need. Our *current* growth might not be sustainable forever, but especially with the resources in the solar system we can keep earth habitable for a long while.

As for the rest, look at our own world.
For the vast majority of time life was unicellular.
Of the multi cellular era dinosaurs, which had a VERY long run with lots of variation never evolved intelligent life capable of extracting metals (as all metals were where they should be, whereas we are moving them around).
Of humanity, Neanderthals, which we would clearly consider intelligent, never developed agriculture.
In fact, for most of our run, neither did we.
Looking at the humans that did develop agriculture, not all then moved into the metalworking / invention stage that eurasia did.
 
Why would you think that? Do you think establishing a colony on Mars would require "massive sacrifices"? I think we could fund it without the public sacrificing anything. And eventually, a Mars Colony will be self-sufficient.



Eventually, but not at first. Mars and Earth could trade easily. Earth and the next nearest colony could have long-distance trade, and by then new trade routes would start where new colonies pop up.

There is a slight difference between being a year away from your world and to be hundreds of years away.
Generation ships would require centuries of work and mountains of top-of-the-line materials, basically by definition the best a civilization can make. You can bet there will be sacrifices.
Space is not like an ocean, it's like a boiling acid bath that provides nothing for life to sustain on and plenty that will destroy it. Unless we master planet-to-planet teleportation, the barrier for space colonization is just too high, even with technologies like space elevators.
 
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Even if there were a bunch of alien space ships out there in the universe, what is the chance that they'd get here? There are a lot of places to go. Not to mention that the journey is pretty hazardous. As the years of a journey pile up, how likely is it that the journey will be smooth and safe?

Maybe the good people of Tralfamadore sent out a space ship a half million or so years ago, and just before it hove into view, a piece of space debris hit it and...poof...another one down. We'd never know.

Depends on the time frame, which is a filter: advanced civs take a long time to evolve, and we may be one of the first, although that's not really a filter.
 
There is a slight difference between being a year away from your world and to be hundreds of years away.
Generation ships would require centuries of work and mountains of top-of-the-line materials, basically by definition the best a civilization can make. You can bet there will be sacrifices.
Space is not like an ocean, it's like a boiling acid bath that provides nothing for life to sustain on and plenty that will destroy it. Unless we master planet-to-planet teleportation, the barrier for space colonization is just too high, even with technologies like space elevators.

Yes, that would be hard for those civs. But what about civs like I described, like us? We colonize the moon, colonize mars, abundant space stations, have outposts at the gas giants to ship back volatiles...would making a generation ship be that much of on an endeavor for that society? Maybe the kind of sacrifices "war production" takes, but I don't see any real impediments in building a generation-ship, as long as the technology is mature enough.
 
So I simply see no scenario in which space colonization would benefit any specie.

Early humans didn't colonize the globe out of any particular benefit for themselves, their society or to establish trade links or anything of the sort. It's a natural thing for humans to do, pure and simple.

Spreading yourself out is a one way to avoid extinction of your genes. Some species are natural colonizers, we call them invasive species and humans are a prime example. Some are not, like crocodiles.

That said, I don't see a non-invasive species building civilizations. Remaining where you are and only exploring new areas that happen to come nearby is not stimulating and it doesn't require an innovative species and innovation is not a major benefit if all you do is to stick around and make do with whatever you have.

It therefore stands to reason alien civilizations will mostly be like humans in regards to colonizing new habitats. Building colonies beyond your star system is a natural extension of colonizing every corner of your own planet.

McHrozni
 
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Yes, that would be hard for those civs. But what about civs like I described, like us? We colonize the moon, colonize mars, abundant space stations, have outposts at the gas giants to ship back volatiles...would making a generation ship be that much of on an endeavor for that society? Maybe the kind of sacrifices "war production" takes, but I don't see any real impediments in building a generation-ship, as long as the technology is mature enough.

what's a civilization's motivation?
What is the possible gain from knowing that, 20 lightyears away, there is a colony that may or may not survive?
There is nothing it can give the homeworld, yet it will have cost decades of global GDP to (probably) send a couple of people to their deaths.

Deep Space Travel MUST make economic sense, or it won't happen.
So show me the Unobtantium or forget about it.
 
Early humans didn't colonize the globe out of any particular benefit for themselves, their society or to establish trade links or anything of the sort. It's a natural thing for humans to do, pure and simple.

Spreading yourself out is a one way to avoid extinction of your genes. Some species are natural colonizers, we call them invasive species and humans are a prime example. Some are not, like crocodiles.

That said, I don't see a non-invasive species building civilizations. Remaining where you are and only exploring new areas that happen to come nearby is not stimulating and it doesn't require an innovative species and innovation is not a major benefit if all you do is to stick around and make do with whatever you have.

It therefore stands to reason alien civilizations will mostly be like humans in regards to colonizing new habitats. Building colonies beyond your star system is a natural extension of colonizing every corner of your own planet.

McHrozni

I disagree: no human has colonized Antarctica, ever, and that is more hospitable than space.
 
I'm looking for Great Filter possibilities. Who has a real good "great filter"?

X-ray bursts. Imagine the Death Star, except that originates from a black hole, and the superlaser remains deadly to life for 100 light-years or more. By that time it is also several light-years across due to scattering.

https://www.nasa.gov/sites/default/files/thumbnails/image/grb_shell_final.jpg

Zap. An entire region of space has not been sterilized. We shall deal with those your civilization friends soon enough.

McHrozni
 
Early humans didn't colonize the globe out of any particular benefit for themselves, their society or to establish trade links or anything of the sort. It's a natural thing for humans to do, pure and simple.

Spreading yourself out is a one way to avoid extinction of your genes. Some species are natural colonizers, we call them invasive species and humans are a prime example. Some are not, like crocodiles.

That said, I don't see a non-invasive species building civilizations. Remaining where you are and only exploring new areas that happen to come nearby is not stimulating and it doesn't require an innovative species and innovation is not a major benefit if all you do is to stick around and make do with whatever you have.

It therefore stands to reason alien civilizations will mostly be like humans in regards to colonizing new habitats. Building colonies beyond your star system is a natural extension of colonizing every corner of your own planet.

McHrozni

Well put.
 
what's a civilization's motivation?

"Motive" could be a Great Filter. Maybe, once you reach a certain level, you don't have a motive to spread out. But I think that's wrong.

I think colonizing will be a built in imperative for any race. How do you protect the species? By putting your eggs in as many baskets as possible.


What is the possible gain from knowing that, 20 lightyears away, there is a colony that may or may not survive?

If you're the homeworld, you get two things: reduced population of the home planet, and an established colony of the home world. A taxable colony requiring lots of protection.


There is nothing it can give the homeworld, yet it will have cost decades of global GDP to (probably) send a couple of people to their deaths.

We're assuming technology that does't "send them to their deaths".

Deep Space Travel MUST make economic sense, or it won't happen.
So show me the Unobtantium or forget about it.

Like I said: Reduced population, taxable colonies, possible tech gain. Both sides benefit in a crowded setting: if you leave, you leave the setting (i.e., planet), and if you leave it also gets less crowded.
 
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what's a civilization's motivation?
What is the possible gain from knowing that, 20 lightyears away, there is a colony that may or may not survive?

Survival represents essentially all purpose of life that we know of. Spreading yourself to two planets in two separate star systems makes your chances of surviving a catastrophe that might strike a world that much better. Of course three worlds is better still, and fifty million worlds is better than any of those.

Deep Space Travel MUST make economic sense, or it won't happen.

All of this applies to just about all knowledge we have of space. Yet, we still send probes to all planets and beyond, we sent robotic probes to Mars and Venus, six human expeditions to the Moon and are making plans to send expeditions to Mars, all without any economic gain. We also build giant radiotelescopes, gravitational wave detectors and particle accelerators that won't give us any political or economic benefit, they're solely there to aid us in our understanding of the universe we live in.

In short, it's what our genes tell us we should be doing. Colonizing the galaxy, the universe, even other universes if were possible would be a natural extension of the drive to go further, explore more and expand to greater reaches. Tangible benefits come as an afterthought.

McHrozni
 
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Like I said: Reduced population, taxable colonies, possible tech gain. Both sides benefit in a crowded setting: if you leave, you leave the setting (i.e., planet), and if you leave it also gets less crowded.

If the Moon was habitable, moving appreciable number of Earthlings to the Moon would be a tall order.

McHrozni
 
It's not even remotely self-sustained, so calling it a "colony" makes zero sense.

Define "self-suistained". You'll find that it's hard to come up with a definition that would make the station anything other than a colony that wouldn't also exclude several countries.

McHrozni
 
Not only do aliens exist, but they are here, and spreading disinformation about Fermi's Paradox by starting threads about "great filters" on various message boards!
 
Survival represents essentially all purpose of life that we know of. Spreading yourself to two planets in two separate star systems makes your chances of surviving a catastrophe that might strike a world that much better. Of course three worlds is better still, and fifty million worlds is better than any of those.



All of this applies to just about all knowledge we have of space. Yet, we still send probes to all planets and beyond, we sent robotic probes to Mars and Venus, six human expeditions to the Moon and are making plans to send expeditions to Mars, all without any economic gain. We also build giant radiotelescopes, gravitational wave detectors and particle accelerators that won't give us any political or economic benefit, they're solely there to aid us in our understanding of the universe we live in.

In short, it's what our genes tell us we should be doing. Colonizing the galaxy, the universe, even other universes if were possible would be a natural extension of the drive to go further, explore more and expand to greater reaches. Tangible benefits come as an afterthought.

McHrozni

Exploration is different to colonisation.

Space is a difficult place to go to. I mean really difficult.

It takes huge amounts of energy just to get there, and travelling any meaningful distance takes huge amounts of time, even if we push the envelope on engine design.

When it comes to the Fermi Paradox, we look at our own civilisation, and we can conclude that aliens have either wiped themselves out with advanced weapons, or they have worked out that birth control is far easier than space colonisation. These ideas are not guaranteed, but it does make sense.

Short of a major meteor strike, we can in theory continue for the foreseeable future on Earth. Space exploration should happen of course. I'm all for the expansion of our knowledge, and seeing what we can achieve, but space colonisation would represent a huge undertaking. It would make the Apollo project look like a picnic. There's a reason man hasn't left LEO since the 70s.
 
Like I said: Reduced population, taxable colonies, possible tech gain. Both sides benefit in a crowded setting: if you leave, you leave the setting (i.e., planet), and if you leave it also gets less crowded.

Just sending a few guys to the moon made a dent in America's GDP. Making a dent in global population by sending people off to another planet is beyond anything we could expect to achieve. How many Saturn 5's (or equivalent) would we need to build?

Far easier to look at birth control.
 
Exploration is different to colonisation.

Of course it is. I pointed it out because The Great Zaganza claimed space colonization needs an economic incentive to happen. This isn't true for exploration or research into basic sciences which produce few if any economic political or other benefits.

When it comes to the Fermi Paradox, we look at our own civilisation, and we can conclude that aliens have either wiped themselves out with advanced weapons, or they have worked out that birth control is far easier than space colonisation. These ideas are not guaranteed, but it does make sense.

Unless Alcubierre drive is something more than a mathematical concept but a real thing you can achieve with a sufficiently high level of technology, space colonization will never be a way to ease population pressures on your home planet. To the best of our present knowledge it's a way to ensure our lineage survives until the end of our galaxy or so, nothing more.

Short of a major meteor strike, we can in theory continue for the foreseeable future on Earth. Space exploration should happen of course. I'm all for the expansion of our knowledge, and seeing what we can achieve, but space colonisation would represent a huge undertaking. It would make the Apollo project look like a picnic. There's a reason man hasn't left LEO since the 70s.

Of course it will. Space colonization is hard.

There are ways to get around some problems however. Use genetic engineering to create a breed of humans who live for a long time, are sterile and have the ability to hibernate and send them, alongside a system that allows for breeding of normal humans. This would be a system that would allow you to create artificial organisms complete with wombs and supportive biological infrastructure (heart, bone marrow, lungs, liver, kidneys, sufficient endocrine support) in an otherwise abiotic supportive case (metal, plastic, whatever). You would also carry a large clutch of genetically unmodified frozen human eggs and sperm with you. Once you'd reach the destination the special crew would come out of hibernation, build the first colony, grow the artificial queens or brood mothers or however you want to call the system and start producing and raising normal humans who would then colonize the new world. You need to produce about 17,000 humans from about 1000 genetically unrelated individuals to virtually ensure a stable population, so it would take roughly a century of growing people that way with ten brood mothers and a dozen wombs per system. You could conceivably replace the highly modified hibernating human breed with robots.

This is all technology that should be doable by the turn of the century. It is unacceptable by contemporary ethical standards, but the same could be said for space probes in 1550s.

McHrozni
 
My filter is that at some point, civilizations realize that they can indeed traverse the galaxy at greater than light speed; in fact, instantly. How? Generations of probes that relay among themselves and back to "the cloud" create the foundation for an expanding knowledge bubble that can be used to create a virtual representation, which is safer and far easier to manage than actually going anywhere. I expect the civilization that takes this step to be AI-based, far less obsessed with the corporeal bias of a need to "be there," since the data from direct and recorded observation "tastes" exactly the same. Secondly, such a life form would have far less urgency in getting quick results, as lifespans could become a meaningless concept.

A virtual Milky Way is just as good as the real one, only better. It's where AIs hang and make fun of the ultra-slow carbon-based dolts they find.
 
There are ways to get around some problems however. Use genetic engineering to create a breed of humans who live for a long time, are sterile and have the ability to hibernate and send them, alongside a system that allows for breeding of normal humans. This would be a system that would allow you to create artificial organisms complete with wombs and supportive biological infrastructure (heart, bone marrow, lungs, liver, kidneys, sufficient endocrine support) in an otherwise abiotic supportive case (metal, plastic, whatever). You would also carry a large clutch of genetically unmodified frozen human eggs and sperm with you. Once you'd reach the destination the special crew would come out of hibernation, build the first colony, grow the artificial queens or brood mothers or however you want to call the system and start producing and raising normal humans who would then colonize the new world. You need to produce about 17,000 humans from about 1000 genetically unrelated individuals to virtually ensure a stable population, so it would take roughly a century of growing people that way with ten brood mothers and a dozen wombs per system. You could conceivably replace the highly modified hibernating human breed with robots.

This is all technology that should be doable by the turn of the century. It is unacceptable by contemporary ethical standards, but the same could be said for space probes in 1550s.

McHrozni

None of this would ease any population pressure on Earth though, as you would only put a small number of people in a ship initially. Sending a generation ship (or similar, as you have proposed) would only give mankind a chance of surviving some planet destroying event on Earth through being somewhere else, it wouldn't address any issues on Earth, such as over-population, or resource depletion.

It is birth control that is a far more efficient mechanism for saving a civilisation than space colonisation.

Getting just 1000 people into space and off on such a journey would be a huge undertaking from an energy point of view, and difficult to justify, as it would have no real impact on population numbers.

An interesting read on space here:
https://dothemath.ucsd.edu/2011/10/why-not-space/

Sending robots, or eggs or uploading our consciousness etc is a different issue, as it potentially involves less resources.
 
None of this would ease any population pressure on Earth though, as you would only put a small number of people in a ship initially. Sending a generation ship (or similar, as you have proposed) would only give mankind a chance of surviving some planet destroying event on Earth through being somewhere else, it wouldn't address any issues on Earth, such as over-population, or resource depletion.

Yes. I did say that space colonization is unlikely to yield anything useful in that regard, didn't I?

It is birth control that is a far more efficient mechanism for saving a civilisation than space colonisation.

Birth control is a more efficient mechanism of prolonging your civilization until the planet becomes uninhabitable, either due to resource depletion, unavoidable and survivable planetary catastrophes or the star dying in one way or another (Earth will be eaten up by the Sun).

Getting just 1000 people into space and off on such a journey would be a huge undertaking from an energy point of view, and difficult to justify, as it would have no real impact on population numbers.

A thousand people would have no impact on population numbers. It's also not enough to ensure a stable colony. Some experts crunched the numbers and came up with the minimum of 17,000 people, either in one ship or in many, but you need that many people to create a viable colony without relying on luck.

That's huge, considering only managed 315 manned spaceflights thus far.

As things stand, unless there is a way to travel in a far more cost-effecient way than we consider possible at this time, space colonization is not a viable way of reducing overpopulation on your homeworld.

There are other ways of course. Build a planetoid space station the size of a small moon, equip it with a reactor that can power it for millenia (e.g. a small black hole, feed it matter and harvest Hawking radiation), and send it on its way. Ships of that size could easily support billions of people. We could call it a Life star :)

McHrozni
 
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I fully agree with the technical difficulties. Also, I agree that population pressure will never be the driving force for space colonization: for the price of moving millions of people to another solar system we could easily build floating cities on all oceans, deep sea habitats and geosynchronous habitats.
 
Even if there were a bunch of alien space ships out there in the universe, what is the chance that they'd get here? There are a lot of places to go. Not to mention that the journey is pretty hazardous. As the years of a journey pile up, how likely is it that the journey will be smooth and safe?

Maybe the good people of Tralfamadore sent out a space ship a half million or so years ago, and just before it hove into view, a piece of space debris hit it and...poof...another one down. We'd never know.

Another goes down, another goes down, Another one bites the dust!!!!
 

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