Grabby Aliens (2021)
grabbyaliens.com
grabbyaliens.com
This would indicate a few possibilities:
1. Expanding alien civilizations are relatively low impact and don't collect all of the energy of stars in ways that are visible to our current telescopes.
2. We are a very early civilization, civs are fairly rare, and we're relatively alone in the parts of the universe that we can see. Civs that are expanding in a grabby fashion started less recently in years than their distance in light years.
3. Aliens expand at close to the speed of light, so there are a lot out there but we won't see them until they're almost here.
4. Something that we have already noticed is actually evidence of grabby aliens, but it is happening in every direction so we assume that it is a natural phenomenon, because it is so uniform.
At the very least, it seems likely that we either we are alone in the galaxy, or expansion is very slow. The idea of "expanding in a bubble of influence close to the speed of light" seems implausible to me, just because of the vast amounts of energy required to accelerate and decelerate to relativistic speeds, not to mention protecting the cargo in transit--when you're flying at .9c, almost every other piece of matter in the universe is flying towards you at you at .9c. Accelerating tiny nanomachine von Neumann probes might be a solution, but how would they decelerate enough to not be destroyed on arrival?
It's all fascinating to think about, at least.
Solar sail being pushed on by the destination star? Or to begin with, even just a “drouge” creating friction against interstellar gas?
So, early humans it propably is.
[1] https://iopscience.iop.org/article/10.3847/1538-3881/ac3416
And, if our theories are right, we're at 4.9% regular matter and 26.8% dark matter, so dark matter is five times as much as regular matter, so that's a lot of aliens...
Dark matter isn't non-luminous matter. It's matter that only interacts gravitationally, but not electromagnetically. This means it doesn't undergo collisions and can't shed angular momentum. It forms a diffuse, largely uniform cloud throughout galaxies. The result is that galaxies are more dense further from the galactic core than we would predict from luminous matter alone.
Dark matter corresponds to option 3 - and there are observations that conform some models of dark matter distribution that match quite well between different galaxies. There are other theories as well, such as MOND (modified Newtonian gravity) that explore option 2 (GR is wrong).
Still, whatever the theory, it's clear that what is not happening is "aliens someone consuming all of the EM radiation from some stars". With anything resembling currently known physics, it's impossible to "consume" EM radiation in this way. Electric charge is always conserved, electrons and quarks don't disappear just because they move around, even with something like controlled fusion. A Dyson sphere would be an extremely hot visible object, not some dark point.
Not my area, but I thought both were known to be incomplete? Q because it presumes a flat spacetime; R because it predicts the formation of singularities that the maths used to develop it assume don't exist?
It wasn't meant to be descriptive, just that there is a gap between theories.
And one theory is there is some 'unknown' type of matter, and they called it dark.
What I meant to write is—
> Dark matter isn't merely non-luminous matter.
5. Controlled transportation between the stars, sufficient for colonization, is sufficiently impractical that there are no grabby aliens within our light-cone.
The dynamics which would make it impossible on any known timespan don't seem currently observable.
Just with state-controlled nuclear weapons we've been on the brink of extinction a couple of times already, the energy levels required for star-travel implies this kind of destructive power being in the hands of even more people (and by necessity more or less out of control of the nation states). A commercial airliner took down WTC, a starship would be an WMD capable of taking out a city (or more).
One implication of this is that there's a chance that we've already invented practical fusion power, but if it's trivial to miniaturize AND weaponize then people in control of it have decided to withhold it to avoid every weird terrorist group creating one.
1: Considering the amount of rocket fuel we need to leave earths atmosphere and reach the Moon, people have been proposing nuclear rockets to reach Mars. That's still within the solar system, reaching another star requires magnitudes more energy, even more so to accomplish enough acceleration to reach another star within a persons lifetime. Such a mode of energy generation not having an explosive failure more feels unlikely (thus making it blow up in a dock is enough).
2: Barring option 1, reaching fractional light speeds, would not a ship need enormously more capable shields than anything today to safeguard humans? The Tunguska event(3-5 mt) was at "just" 27km/s of a 50 meter object.
3: Speaking of Tunguska, even if the ship itself would lack such shields (however a human would be expected to survive w/o one), a ship capable of interstellar travel should be able to push out a rock and then accelerate it back to earth to create a Tunguska (or larger) event at a target location.
The core issue is the energy levels required(1), converting them to something destructive is usually within grasp of less intelligent people than those that research the advances that make them available.
1: https://www.sciencedirect.com/science/article/abs/pii/009457...
TL;DR; quotes 10^20 joules of energy, as the article says equivalent to complete fissioning of 1000 tons of Uranium.
To get a ship to hit the ground at the velocity you’re talking about a large chunk of it would need to be solid steel like a bullet basically. Space craft aren’t built like that, they need to be mostly empty space for storing propellant and people. A reactor and its shielding might survive but that’s on the scale of 5 - 10 meters and it’s still not 100% solid so it doesn’t compare to a large metallic asteroid.
Throwing rocks at a planet might work but you need the right equipment and expertise to bullseye a planet from 100 million miles away and if anyone saw you do it they could take their time intercepting the rock.
Hand waving away “we can’t travel through stars” because we currently don’t get it, seems like the weakest way to discuss the topic.
You/we can’t imagine it; so it must be impossible or in practically difficult? What if it turns out to be extremely easy, we’re just extremely small or extremely uninteresting? Those are far more likely topics than we already have the answers and have decided it’s not possible.
Even if our first interstellar colonies diverge immediately and some even turn into reclusive hermits, some may expand, repeating the cycle.
BUT, that this will be one of those very difficult tasks, so it will take many thousands or millions of years.
And so goes towards 'we are early'. So, if we are grabby, and all the other grabby aliens, are all still getting over this transportation hump.
This whole discussion is about being 'early'.
Not sure you are making a point.
Edit: The original post discusses below light speed transportation. 25% speed of light is used in the estimates.
But guess I agree, if no aliens including us, never-ever with infinite time ever develop transportation that can get up to some fraction of light speed. Then maybe no colonization ever happens, and the grabby guys stay in their system.
“We can't see any evidence because there is nothing there to see” is a possibility, grabby aliens _requires_ significant-fraction-of-C travel for the argument to hold, and it's entirely possible that it's just impractical-to-the-point-of-impossibility. (That's why I quoted it in another comment).
Yes, it's possible that we're early. It's equally possible that we're “early” because there's no concert: _everybody_ is early in a universe where the band never gets on stage and it turns out that nobody bothers colonizing the universe due to the cost and lack of benefits.
See also: “Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that".” https://news.ycombinator.com/newsguidelines.html
And I can ask for clarification concerning if you read the original post, since your objection/point was already covered.
Did you read it and simply making some additional argument against it, or did you miss it entirely?
"5. Controlled transportation between the stars, sufficient for colonization, is sufficiently impractical that there are no grabby aliens within our light-cone. "
This is covered in the other points of the theory? So should I assume you read it?
"The universe isn't a rock concert, “we're here too early” is not the only possible reason why there's no band on the stage. "
"Don't be snarky. " https://news.ycombinator.com/newsguidelines.html
Ofc there are explanations for that part of the paradox as well, but the impractical travel theory doesn't cover it.
The data is analyzed as a dynamic system. Radar just looks at a bounce. If you setup radar incorrectly you might get false hits and no returns on valid targets. If you use a wrong model in analysis of astronomical data you're never getting anywhere close to a correct result.
Could you elaborate why not? All current technology I know of has an efficiency of <100%, with waste energy being lost as heat (which in space would be radiated away in the infrared spectrum). Why would this not be the case for a hypothetical dyson sphere or swarm?
Of course everything radiates heat I did not think I have to get down to that level in commenting here.
The question isn't whether Dyson speheres radiate, the question is can we detect an artificial megastructure and my answer is no, based on the hypothetical Dyson design.
Other megastructures might be discovered through the same methods as exoplanets.
You mean like brown dwarfs?
R_sol^2T_sun^4 = R_shell^2T_cmb^4 (R_sol^2*(T_sun/T_cmb)^4)^(1/2) ~= 2 light months.
Yes I mean why not. If you are an expansionist advanced civ, travel is impractical and you have enought time and resources then what else is there to do?
Obviously there are explanations "why not" (as I said), but insterstellar travel unavailability is not one of them.
I know two things.
1. We are now already using heat mask measures, even when we are very young civ in terms of Kardashev scale. We already use simple slit heat emitters in military tech (many Stealth planes have slit nozzles and for example, Leopard tanks also use slit exhaust for same reason).
2. Even we now know about possibility of laser heat, which could emit heat directly with very high focus.
In conclusion, idea is, to surround whole civ with heat mask blanket, and make all heat exhausts directly focused on directions, where now observer expected.
Second, looks like our development now is very slow, because it should be on early stages (Kardashev scale), and old civ's should know this.
And I now support theory, that we are fortunate to be far enough, so stronger civ's are not interested in spending resources to limit our development.
I even consider might be exists some preservation pact between Big civ's, to avoid touch young civ's, for some purposes like scientific, or arts. So yes, basically, I support Zoo theory.
Although focussing emissions (not really a blanket) is possible, not only would some specific civilisation have to actually do that, it would have to be a common enough choice that every example we would otherwise have been able to see actually does choose to do that that — this gets increasingly difficult the more such examples there are: if a civilisation can build a Dyson swarm, what are they afraid of that they would want to hide? Even if one civilisation has a reason, everyone has to make this decision, regardless of how many (or few) "everyone" is.
"Dark forest" is a bad reason, as everyone with a Dyson swarm will have been able to know your planet existed and had life on it even when it was all single-cell species; a star winking out of existence is noteworthy, and easily noticed[0].
One Dyson swarm is enough to directly colonise a high percentage of all galaxies that aren't beyond the "reachable horizon"[1] of the universe. As soon as we can make artificial self-replicating machines (we know such machines can be made because all life is self-replicating nano-machines, we just don't know enough to do it completely from scratch yet), this would take us about 31 years[2] to make such a swarm.
[0] So easily noticed that we have, in fact, noticed it: https://vascoproject.org/vanishing-stars/
[1] the "reachable horizon" is how far stuff can get from here starting now given the universe is expanding and no FTL: https://upload.wikimedia.org/wikipedia/commons/8/88/Home_in_...
[2] https://www.lesswrong.com/posts/DvQ7cYxhnrZtWngvW/how-to-tak...
They assume, when have already working general AI technology and it have some limited size (volume-mass-energy consumption).
Unfortunately, we still not have GAI and even cannot predict, how large will be first practical unit.
Must admit, looks like we very close to do it, but from history of previous great technical inventions, some things takes decades to achieve production status and was repeatedly reinvented in some years after another inventor fail.
It is also possible to have a large system where humans are just a component, if this were necessary. The human-machine ratio is a function of how close the automation you have is to what you need.
If you programmer, you should know from experience or from learn, that in complex system possible just two ways to achieve reliable execution.
1. Brute force, just test as many possible scenarios as could, 99.999% is better than 99.99%, and make script for each scenario.
2. Smart, run system when tested somewhere between 70..90% and make some sort of insurance, so when happen non-tested scenario and all failing, you will pay (compensate) for harm, and make additions.
That is. Bacteria lives in comfortable environment (mostly in liquid water drop), and spent billions of slightly modified reproductions, to make solutions for all possible scenarios. You may hear, DNA of simplest bacteria are more than Million pairs, that's because of number of scenarios it successfully survive.
Space is much less comfortable environment than liquid water, it have wide range of possible parameters, I even not sure if exists some structure, which could survive in all possible space environments, so need some adaptation mechanisms, to change structure, and best is consciousness AI, which could make smart predictions of causes and reasons, and control all these machinery. And also it will have memory, to repeat moves which helps to survive when something similar happens earlier.
Irrelevant. A self-replicating system does not need to be highly reliable. Look to the past, any time over 200 years ago most families were a dozen kids because most didn't reach adulthood.
> That is. Bacteria lives in comfortable environment (mostly in liquid water drop), and spent billions of slightly modified reproductions, to make solutions for all possible scenarios. You may hear, DNA of simplest bacteria are more than Million pairs, that's because of number of scenarios it successfully survive.
False. Bacterial environments are hostile because other bacteria fight them for the same resources, including predation. Many chemicals are hazardous even in small quantities. Internal chemistry requires water in liquid form, yet there's only a narrow range of temperatures where water is liquid, and worse the chemical processes change rate significantly even within that range.
Also irrelevant, we've been using simulated evolution as a form of AI for ages already. It's not new or novel. I implemented a version of this in 30 minutes over a decade ago just to prove a point. A million bases is trivial to store, so is a billion or a trillion.
> Space is much less comfortable environment than liquid water, it have wide range of possible parameters, I even not sure if exists some structure, which could survive in all possible space environments, so need some adaptation mechanisms, to change structure, and best is consciousness AI, which could make smart predictions of causes and reasons, and control all these machinery. And also it will have memory, to repeat moves which helps to survive when something similar happens earlier.
Also false.
1. Space has far fewer parameters than water.
2. One does not need to make a single machine to survive "all possible space environments" to do this, just our solar system at 0.47-0.31 AU from the sun. We already have that, we sent probes there.
3. Consciousness is not necessary for any of that. Neither is episodic memory (though that is trivial to implement). Bacteria exist and do these things well enough with mere DNA.
Do you know mathematics? Calculate, how slow will become your Dyson swarm, if for example only 1/20 will survive?
BTW, you may hear about baby-boomers, and they are exactly caused by much improved medicine, now in EU survive near 100% children.
Calculated? Ok, now calculate, how much suffer probability of overall success, because limited resources does not accept to make 20 turns to achieve 1 successful?
> 2. One does not need to make a single machine to survive "all possible space environments" to do this, just our solar system at 0.47-0.31 AU from the sun. We already have that, we sent probes there.
Well, now I see you are just overweening human, but without real knowledge. Solar system is itself have wide parameters spectrum, but is is also significantly different from other stars environments.
> Bacteria exist
Bacteria have sacrificed billions lives, to gather information, to achieve current success rate.
But must admit, I will consider idea you suggest me, about send hopeless missions, to just gather info, and I'm sure you also lazy, so I'll myself calculate success rate for each sacrifice rate.
It means the real reproduction time is t/f, where t is the time it takes to make a single unit and f is the fraction of units which survive to further reproduction. For 1 in 20 surviving, that means the real reproduction time is 20t.
Some bacteria take 30 minutes for a single reproduction, so that with a 1/20 success rate would be an effective population doubling every 10 hours. An E. coli cell weighs 1 pg, and this is only a factor of 2^128 from the planet Mercury. These random example numbers would therefore be able to consume the entire planet in 53.32 days. At this level, almost all the time (97%) is spent on waiting for the solar panels to supply enough to get the stuff from the planet's surface to solar orbit.
> Calculated? Ok, now calculate, how much suffer probability of overall success, because limited resources does not accept to make 20 turns to achieve 1 successful?
I have no idea what point you're even trying to make here.
We know we don't need to worry about your 1/20 random example for humans because we know ourselves; only the machines need this consideration. That's a number which you made up, and your own complete fiction is what you're now trying to use for an example that I don't understand.
> Well, now I see you are just overweening human, but without real knowledge. Solar system is itself have wide parameters spectrum, but is is also significantly different from other stars environments.
Completely irrelevant. I don't even know what point you think you're making. I linked you to a specific plan to build a Dyson swarm specifically in our solar system at the orbit of Mercury. The rest of the universe is irrelevant to this part of the plan, for exactly the same reason and in exactly the same way that it is irrelevant to bacteria on Earth that the rest of the universe exists.
What you do with your Dyson swarm (including colonising the universe) only matters after you've built your Dyson swarm. Building one is fast the moment von Neumann machines can be engineered rather than grown, and give you such an incomprehensibly large industrial and resource base to work from that comparing it to what we have access to today is more extreme than asking a single pre-writing cave painter to imagine our current entire world.
> Bacteria have sacrificed billions lives, to gather information, to achieve current success rate.
So?
Expansion at c is very unlikely. Insane things happen when you approach c, like the cosmic microwave background transforming into a gamma ray laser aimed at your head and collisions with microscopic particles destroying you. It may be that travel close to c is so hard as to be effectively impossible.
I’ve read that speeds up to about 30% the speed of light are “thinkable” with currently known physics plus advances like compact fusion reactors. Think something that looks like the Epstein Drive in The Expanse or the ships from Avatar.
These models provide indirect evidence against the existence of FTL travel. If FTL exists it means we really have to be extremely early, maybe even the first in our galactic cluster. Otherwise someone would have visited at least.
I also think if someone has visited, such as if some tiny number of UFOs are actually of ET origin, it means we are probably incredibly lucky to have neighbors that aren’t “reapers” in the dark forest sense. It’d be funny if our galaxy is actually full of aliens and we lucked out and are camped next to some superintelligence that is both benevolent and powerful enough to fight off anyone who isn’t. So hey if they’re taking our cattle maybe that’s a pretty small price to pay.
The presumption that other putative galactic civilizations start at nearly exactly the same time as us is implausible, especially considering more than 9 billion years passed before the solar system even formed.
Everything else is cope.
If you include other galaxies, then they would've had to have been silent since the beginning of time.
Also, non-living matter spontaneously forms into living matter by no known mechanism.
If you're going to believe something religiously, make it something less trivial than muh aliens.
Like just throw in the towel bro. You're adding epicycles on top of epicycles when the answer is right in front of you. You're just too stubborn to admit you were wrong.
* Brown dwarfs: These are objects with masses too small to ignite nuclear fusion in their cores and shine like stars. However, they are still warm enough to emit infrared radiation.
* There are rogue planet candidates that do not belong to a solar system.
> Furthermore, we should believe that loud aliens exist, as that’s our most robust explanation for why humans have appeared so early in the history of the universe. But if loud aliens will soon fill the universe, and prevent new advanced life from appearing, that early deadline explains human earliness.
Even furthermore, we should believe that Big Foot Medusas exist, as that's our most robust explanation for why humans have not seen these yet and are still alive. Since Big Foot Medusas turn everything alive into stone upon observation, and we are still here, it suggests we are early in our explorations and observations of Big Foot Medusas.
Anyway, a loud grabby alien civilization expanding is "first come, first serve". Perhaps we have not seen grabby aliens, because the first grabby aliens became quiet, and make new grabby aliens impossible, or they finally became superrational and realized they need more than one civilizations to have an economy, cooperation, cosmodiversity, or competition: If aim is to win at tennis, you can't play tennis alone.
As for earth specifically, it was probably already grabbed, and humans are the terraforming organisms put in service of the grabbies to make our planet habitable. Or the grabbies are in such a zeal to expand and get the most of our galaxy that they focus on planets that are close to the horizon, after which they will be moving away at faster than light speeds due to accelerating expansion of the universe. Only after that will they get around to Earth (first building a Dyson Sphere around the universe to harness its energy).
The most robust explanation for why we're here now is that unlikely things happen all the time, and we only think that's weird because of anthropic bias.
Now there's a thought.
The question being asked is not: "Why do we not see grabby aliens?"
The question being asked is: "Under what circumstances can humanity become grabby aliens that colonize the galaxy in reasonable time given that we do not see grabby aliens?"
The simplest circumstances that would allow humanity to become grabby aliens in the future is that becoming grabby aliens is easy for a modern human-like society. However, grabby aliens that colonize the universe in reasonable time preclude humanity from existing if we intersect with their existence.
That means there must either be something else special about our existence, or that we are unlikely to ever become grabby aliens. That is the entire point of the thought exercise, figuring out if there is a hope that humanity will become grabby aliens (Star Trek).
You talk as if being a loud grabby alien to other space civilizations is a hopeful thing for humanity to aspire to. Did not Star Trek had a Prime Directive for some reason? Though I do like solving the Fermi Paradox by humanity taking a good hard look in the mirror. May disprove us being Big Foot Medusas with one stone too.
Humanity just got rid of a nasty period of colonizing space on earth. I would not let us near intergalactic space without a time-out period.
If we assume that every intelligent species will turn the universe into goo within 10,000 years of achieving human-level technology, then that is only compatible with the fact that the universe is not currently goo under very limited circumstances. Again, I am not arguing that is the future or desirable, I am merely stating that if you believed that then you must also believe that we are also in one of those very limited set of circumstances. Otherwise you need to rethink your beliefs.
The analysis made in the article is: "Assume you want humanity to expand to the stars and that humanity is not special or unique in temperament so aliens will do so as well. Humanity can only come into existence under a limited set of parameters and there are only a limited set of parameters that explain the data we have available."
> If we assume that every intelligent species will turn the universe into goo
The analysis made in the article is of similar bad form. If I am arguing a meaningless point, I suspect that is due to the all-round meaningless points I am responding to.
Being among the first civilizations in the galaxy is less special than being the first civilization, but more special than being just another in an ongoing ecosystem.
I want humans to be casually interstellar and expand across the galaxy. I want this to occur in less than N years, N << 10^10.
If humans are casually interstellar and expansionist, then we would colonize the galaxy in M years, M << 10^10.
Humans are not special, therefore if another alien species existed in the past at current human tech levels, then they would do the same as humans would and colonize the galaxy within N + M << 10^10 years after achieving current human tech level.
We believe we can detect such a civilization. Therefore, if we are more than N + M years after a another civilization with current human tech level, then we would see them.
We do not detect any such civilizations.
Therefore one of the assumptions must be wrong.
1. We can not detect a galactic civilization.
2. No alien civilization has reached current human tech level within N + M years of now.
3. Humans are special. Only humans would colonize the galaxy if they had casual interstellar travel.
4. Humans are not special, but we will never invent casual interstellar travel/spread to the stars.
So, if you think humans are not special (3 is false) and you hope humans will spread to the stars in the future (hope 4 is false), then you hope the answer is 1 (humans are bad at detection) or 2 (humans are early).
If you rule out 1 and 2, then 4 can only be true if 3 is true. If you rule out 3 as well, then you must conclude humanity will never spread to the stars for unknown reasons.
Isn't 4 equivalent to, 'no civilization will invent casual interstellar travel/spread to the stars'?
And isn't that hypothesis extremely likely, given what we now know about the costs of _interplanetary_ travel and its relative ease compared to interstellar travel?
That's another assumption, that it's _possible_ to colonize a galaxy from a planetary base. We don't even know that it's possible to colonize a nearby planet. If we were confident that we could, we'd be filling up Siberia, Ellesmere Island, and Greenland first.
There's also another assumption missing from your list- that technological civilizations can last long enough to colonize the galaxy. I'm also surprised that there isn't any discussion on the site or here of Great Filters. If the average technological civilization wipes itself out within a few hundred years of developing technologies that enable space travel or even radio, then all discussion of "filling the galaxy" is castles in the air.
As an example of the latter, look at birth rates in different societies on Earth: Almost universally, they decline to replacement level once they hit a certain level of per-capita wealth.
It’s very likely that a society that achieves interstellar travel will do so after it achieves the ability to provide the highest standard of living for all of its members indefinitely using just the resources of its local system. This already describes Earth; the reasons we don’t do this are ideological, not based on any inherent constraints, while interstellar travel isn’t in our grasp yet and is likely to be extraordinarily costly.
Such a society wouldn’t face any pressure to grow, so any colonization would itself likely be ideological—“We don’t want to do things Surak’s way, let’s pull up stakes and find a world where we can live the way we want!”—or as a contingency/hedge against large-scale existential risk. Neither demand colonizing even a small fraction of a galaxy, assuming habitable worlds are even remotely plentiful near and reachable from the origin world.
Maybe (4 is false) is inevitable now that humanity has reached its current point. Maybe literally every human-like species will become Star Trek and enclose every star in a Dyson Sphere; that would be awesome since it means our goal is now a foregone conclusion. But how would we know? Well, we can do a thought experiment assuming it and extrapolate toward characteristics that we might be able to detect to falsify our hypothesis.
Well if literally every human-like species will enclose every star in the future, then we should not be able to see any stars at some point after one comes into existence. We can still see stars, therefore either it has not happened yet (1), there are no other human-like species (2), or the supposition is false (3). If the supposition is false, then there are risks ahead of us. If the supposition is true, then the risks are behind us, but then (1) or (2) must be true. For (1) to be true, we must either be early or it takes a long time. For (2) to be true, we must either be early or rare. If we can rule out (1) and (2), then we must conclude (3) which means we can be confident that there must be a risk ahead of us preventing us from reaching our goal that we as a species need to be wary of even if we do not know what it is specifically. We just know it has to exist otherwise we would see no stars.
If (1) or (2) is true, then (3) no longer needs to be true. It might still be the case that the goal is impossible, but at least we have a chance. The point of this analysis is trying to theorize where we need to look that gives humanity the most information about if and how to become Star Trek. It is not about coming up with the "correct" answer; we do not have enough information for that. We are trying to create theories that take facts that we can find (or can in theory find) as inputs and generate predictions that can be tested and falsified.
Costs are a function of manufacturing productivity. What is the upper bound on manufacturing productivity? With automation and AI, I don't see any hard upper bound.
The raw resources are certainly available to build starships. I mean, your share of per capita energy consumption over your life would be enough to accelerate your body to maybe 700 km/s, and that's with us just using a small fraction of the energy available on a planet; energy in space would be many orders of magnitude more abundant.
It is one idea anyway. It would be bizarre for us to end up some precursor species...at least in our galaxy.
It doesn't scale well. The probe would be able to observe a carefully chosen extrasolar planetary system in the opposite direction in relation to the sun. If you want to observe a second system, it's necessary to launch a second probe 550 AU in another direction. You can't change targets just by rotating the probe, given its lens is the sun.
A significant difference of the solar gravitational lens from a conventional telescope is that the gravitational lens telescope is not in any practical sense pointable.
For the telescope at a distance F from the sun to be re-aimed to image a new target 1° away, it would have to move a distance of (π/180°)F, which is 10 astronomical units at the minimum focal distance-- a lateral distance equivalent to the distance from Earth to Saturn.
This means that, in practice, such a telescope is not able to be repointed.
Thus, a telescope at the gravitational focus is necessarily going to be a singlepurpose telescope, with the target of observation selected before the mission is launched.
A gravitational focus mission can’t be used as a telescope to search for a target: such a mission must be with the objective to observe a target whose position is already known.
Geoffrey A. Landis, NASA John Glenn Research Center
https://www.nasa.gov/general/thin-film-isotope-nuclear-engin...
> The basic concept is to manufacture thin sheets of a radioactive isotope and directly use the momentum of its decay products to generate thrust.
Actually it's mentioned at the end of the article:
> Novel ability to reach deep space (> 150 AU) very quickly and then continue aggressive maneuvers (> 100 km/sec) for dim object search/rendezvous and/or retargeting telescopes at the solar gravitational focus over a period of years.
Imagine that by some chance Mars was another Earth with a breathable atmosphere. NASA would have been given a trillion dollar budget and we would have been there in the 80s. Instead it’s a dead red rock so NASA gets a small budget and the US spends its money on blowing people up instead.
We have the technology to be a spacefaring civilisation but we won’t care until Earth becomes a worse place to be than the rest of the solar system, which is probably never given how bad the other bodies in the solar system are. Most likely we develop Von Neumann probes before we ever get bored of Earth.
Watching a planet which could retain water go from "nothing to oceans" would be amazing.
I'm not sure how that would get solved without some active technological solution by humans let's say.
Which is short in geological terms, but an eternity in technological ones. We would have plenty of time to solve that problem.
It appears that at some point, somebody involved with this knew what they were doing. But we are removed so many steps from that person, that anything said there could as well be Star Trek techno-jumble. Including the conclusions.
Or that perhaps we're a simulation.
We exist in a very interesting time in history when the pieces are coming together.
Our hypothetical future robot descendents may be very interested in learning about their past.
>Wake up
>No idea where I am
>Hey we have no idea where everyone is
>According to history nothing much has happened in the universe
>Oh look at that, just now that you are alive you are hitting the singularity
Feels a little like a rehashed sitcom episode...like a director is just brute forcing shit to figure out a solution, with our lives. And its all probably just on how to make a good cup of coffee for his interdimensional space ship.
With software that encourages emergent behaviour we are unaware of the abilities the entities take on. So in theory I think we could.
The better question is if it even matter.
This is kind of why I mostly find the discussion of whether we're in simulation to pretty quickly reach a point where it stops being interesting even from a philosophical perspective. I don't really see how you can differentiate between fundamental properties that we observe that reflect the "real" universe where we're just a simulation and fundamental properties that explicitly designed for the purpose of the simulation itself and may not actually reflect the "real" universe. We might as well ask if the OS our simulation is running on has a toggle for dark mode or not.
Belief is simulated knowledge and we exist within our believed world...so we are in a simulation of some kind, but we don't know if we are also in "the" kind.
I suggest googling David Grusch to read about the whistleblower from inside US intelligence services. Also search for “Navy Rear Admiral Tim Gallaudet ufo” and you’ll find additional comments.
This is the greatest coverup in human history.
Do you also think North Korea, Cuba, and Iran either don't exist or want to be part of this coverup? Do you live in a world where there's really only one government and any indication to the contrary is mere kayfabe?
In the lore, multiple governments are involved in the conspiracy. They keep it secret because it is a race to see who can crack the alien tech the fastest.
There have been cases in the lore of other countries (Brazil and Zimbabwe i believe) having encounters or alleged down aircraft and the US has came in to investigate/recover the down object.
I don’t think there is a world government, but i do think we cooperate with each other.
Also President Clinton says he tried to get information on UFOs but they refused and gave him the runaround.
Must say, from practice of living on fast changing territory, it is very typical for people to hate all new, because sometimes new things appear too fast, that just their appear are pain.
This is not something supernatural. Even more - for people is natural when things are NOT change fast, even when all these new things are good. I'm sure, you will admit, from steam railroad there was many things very scary. And Iranians have right to say, that English and Americans opened this Pandora box.
In 1st world, changes are just literally changes, may be you retire later or your deposit will become smaller for few bucks.
But in "3rd world", life is extremely fragile. Most people does not have savings, and typically to not have any safety measures, just because constant under-financed. For example, in India, great disaster, when temperature falls below zero - every time this happen, people die.
So, people in 3rd world typically consider literal daemon everyone who do risky things or ask others to do risky things. People even could literally kick somebody for talking about risky things.
Also, the theocratic leadership of Iran is not so fragile.
You're confusing leadership and economy. This is very significant difference - when economy suffer in first-world, whole world hear this from independent press, but when similar thing happen in countries like Iran, people are killed if try to open truth, because leadership pressures to open just info it think should be open and nothing more.
For example, when in North Korea happen great hunger, nobody outside country knows except CIA.
In countries like Iran, NORMAL higher education just does not exist. For example, I lived in USSR, where instead of Philosophy learned history of communists party. Imagine, what happen with other knowledge, which communists considered harmful - laws and rights, journalism, history, diplomacy - they just substituted whole parts of science with their surrogates.
Read. Use your rights to obtain real information, not surrogates. https://en.wikipedia.org/wiki/Juche
The Fermi paradox is only a paradox due to the assumption that in a few million years a civilization will colonize the entire Milky Way just because it's theoretically possible, so we should be up to our eyeballs with aliens' von Neumann probes. But many things are theoretically possible. We could build the world's largest house -- the size of Nebraska. Every nation could reorient and sink their economy into that megaproject and do it. But it's irrational to; there's better things we want to do with our resources (which will always be finite, all the way up the Kardashev scale). That's why I think it's silly to expect any intelligent life to be that ambitious (or competent).
"We estimate that loud alien civilizations now control 40%–50% of universe volume, each will later control ∼ 10^5 to 3 × 10^7 galaxies, and we could meet them in ∼200 Myr–2 Gyr." Those numbers seem inconsistent.
"Ours is a model of grabby aliens, who by definition (a) expand the volumes they control at a common speed, (b) clearly change the look of their volumes (relative to uncontrolled volumes), (c) are born according to a power law in time except not within other GC volumes, and (d) do not die unless displaced by other GCs."
That's an interesting set of assumptions. Kind of a 1960s science fiction model.
If we now have a reasonable understanding of physics, you get a different model. No FTL, radio works at light speed,
Technological civilizations may not last all that long. Human civilization is about 6,000 years old. Heavy industrial civilization is about 200 years old. Most mineral resources already are past the point where the easy stuff has been mined. The USGS tracks total worldwide mineral resources.[2] On a scale of years, things look good. On a scale of centuries, not good. On a scale of millennia...
[1] https://iopscience.iop.org/article/10.3847/1538-4357/ac2369/...
[2] https://www.usgs.gov/publications/mineral-commodity-summarie...
Control strategy simply has to adapt accordingly: i.e. a message probably comes with a fleet sufficient to ensure its obeyed.
This was one of the ideas in the Doom novelizations: that the aliens had spent so long travelling that there was little chance of victory because of you attacked a place you took along everything needed for overwhelming victory.
I only wish Alcubierre-type drives were as well-developed as that.
Probably not. Historically, a few months of lag is roughly the upper limit for running an empire. The Roman empire got round trip lag down to two months to the distant provinces. The Spanish empire was at 4-5 months of lag for the New World. Holding an empire together with a lag of decades probably won' work.
If travel times are orders of magnitude longer than lifetimes, then you will tend to lose civilizational cohesion.
> Control strategy simply has to adapt accordingly: i.e. a message probably comes with a fleet sufficient to ensure its obeyed.
What even is the point? The message takes N years to be received by a receiver N light-years away, but travel times will be orders of magnitude longer, so no "fleet" can be sent.
Of course, there's a fair chance that by the time the fleet gets there, the colony is long dead, or has advanced in weaponry in a different but overwhelming direction, so they just barely notice the little flash way out past their oort cloud.
You look at running an empire with hundreds of years of message delay as pointless, they may view it as totally necessary. After all - if from your subjective opinion you blink and you're in another star system (hundreds of years later), then are you even worried about that time difference, or are you worried about whether they're still flying the right flags when you get there?
(you can imagine a similar arrangement of times working out for social relationships over such timespans - duration might not much matter if everyone sort of agrees they'll wake up for X amount of subjective time before meeting up again in person).
Instead of FTL, or FTL communication lines, or forms of suspended animation.
The ships that are sent out could be run by an AI. Maybe the ships are factory ships to self-replicate.
The Grabby could be more like Blindsight.
I'd call them "lineages" for this reason, but I don't really expect the name to catch on.
Or maybe we are sui generis and about to embark on such a program. Or maybe we are about to run headlong into another's such program, possibly causing conflict. Or maybe it's all much too unlikely. I wouldn't know.
But if the universe will soon be filled with gajillions of grabby aliens, who's to say that we couldn't have been born as grabby aliens instead of humans? In fact if there will be so many of them, isn't the fact that we're not grabby aliens ourselves evidence that there will be no grabby aliens?
I feel like there is some implicit assumption about 'who you are likely to be born as' that I'm not getting here. Do I need to assume that I could only have been born as a human for the argument to go through?
Or at least, it doesn't rule it out. Non-grabby aliens aren't visible in this model; given the distances, "grabby" is the only way to change the environment enough for current human tech to even notice something unusual.
Incidentally, Carl Sagan used the above line of reasoning as a sign that human civilization was going to collapse before a few more doubling times.
The weakness of the mediocrity principle is we're in a lot of categories, and we can't be near the middle of all of them at the same time.
This paper makes one particular assumption about what's a good set of things to be mediocre about; I think that's the weakest part because it's so easy for intuition to mislead there.
So I could invert your surprise: No more so than finding yourself in the last of a few trillion things that evolved into humans.
1. We are now already using heat mask measures, even when we are very young civ in terms of Kardashev scale. We already use simple slit heat emitters in military tech (many Stealth planes have slit nozzles and for example, Leopard tanks also use slit exhaust for same reason).
2. Even we now know about possibility of laser heat, which could emit heat directly with very high focus.
In conclusion, idea is, to surround whole civ with heat mask blanket, and make all heat exhausts directly focused on directions, where no observer expected. BTW this could be evidence of mature Civilization, when see strange space objects, which looks like Black Hole in most directions and extremely bright in some "featured" directions.
Second, looks like our development now is very slow, because it should be on early stages (Kardashev scale), and old civ's should know this.
And I now support theory, that we are fortunate to be far enough, so stronger civ's are not interested in spending resources to limit our development.
I even consider might be exists some preservation pact between old Big civ's, to avoid touch young civ's, for some purposes like scientific, or arts. So yes, basically, I support Zoo theory.
But for SETI it could be golden earth - if really waste heat emitting there, should be very different view (vs view from near some star).
What if this is part of Drake equation which we missed?
While I'm not an expert, it appears that by observing life on Earth (not just humans), groups of living things do not expand linearly, and eventually hit an upper limit (this happens at all scales, from colonies of bacteria to entire civilizations).
Who's to say that other "loud" aliens haven't already expanded and begun spacefaring, but simply are not expanding out to where we are?
…but we’re still a young civilization, and are extrapolating from very little data. It could be that we’ve yet to encounter most of those inflection points. Maybe the next one is “the Singularity” - but beyond that we really have no idea.
All of this is consistent with humanity being very early on the timeline of the universe.
This 'grabby' alien and 'light cone' discussion is explaining , or one solution to the Fermi Paradox.
By definition if they're loud and we can't see them, they're not within the volume of our visible universe.
> I might be missing something here, but why would alien (or any) civilizations continually expand at a constant rate?
This assumes they keep multiplying and colonizing outward. There is no real upper limit - except, eventually, the accelerating expansion rate of the universe that keeps them from reaching further. Because the colonized volume is so large, we don't really assume these colonized volumes form a coordinated empire. It would be more like a loose tangle of city states spread across a vast landscape. They might share common heritage, technology and some amount of culture, but be otherwise independent.
With aliens, with a different culture, civilization if that concept applies, language or not, and enough technology to make interstellar travel, and all of that for thousands to millions of years, those aliens that are far beyond our imagination, well, somewhat we know how they think and should behave, now knowing the technology they should have, the knowledge about the universe they should have, philosophy or whatever.
We don't even know if it will be ever practical interstellar travel, because we didn't reach that stage yet. In theory it should work... in theory I could climb stairs till reaching the moon too. People is too busy trying to figure out how advanced aliens should think, and didn't stopped to analyze how they are thinking.
By using our knowledge of physics, we can make reasonable speculation on what is possible and not possible, and what engineering we need to do to make these effort successful. Some people's work are so successful that they became foundational to our knowledge base today.
Same as with aliens. We can make reasonable extrapolation on what we might see from the type of aliens that expand versus and aliens that don't. They are of course, guesses, and those guesses continued to be argued and refined. Note that the site doesn't assumed that all aliens are grabby, only that some are grabby aliens, and try to extrapolate on what it might look like if they are grabby.
Our speculation is only as good as our understanding of physics. Which is pretty good! But people in 1800s thought they had discovered just about everything to be discovered, and thought themselves at the end of physics, too.
We can only reasonably speculate using our existing knowledge base. Doesn't mean that people literally think we know all there is to physics. People even acknowledged that it's incomplete.
Those are really interesting claims you make. Very often I see the exact opposite claims out there: humans have almost no idea what the god(s) are really thinking, and religion seeks to contrast itself from the surrounding culture.
(that's not the biggest philosophical conflict I see in religious discussion, but the other is Christian-specific)
What is that technology? Technology that can only be created by a harmonious society working together to share ideas and combine ideas from everyone in a non competitive manner.
In that way the universe ensures peace and harmony ensures knowing that warring civilisation aren't able to leave their home base nor communicate with the universe.
It might sound slightly esoteric and spiritual but there many ways to societally live together in harmony with all humans.
After all not one individual can completely understand the universe, how can one nation hope to reach out to a non understandable universe.
And as We, I do not foresee only human beings, but more broadly the Living, as We, interspecies from Earth. Finding a way to unite individualities should include ways to establish communication channels with so-called wildlife individuals.
The idea of considering such a path being esoteric is a way to get distrustful people on board, which may be a waste of time and resources. We should focus on uniting everyone who already think this is the new normal.
And yes, we should start at home and begin communicating with our surroundings. Be it the planet or the species with whom we share this spaceship earth.
Just as we can't imagine a harmonious society, so we can't imagine the technology that would arise from such a society.
It's a recursive argument, I know, but that's the core of the problem.
Perhaps we are using technology in different context. I mean understanding of physics + a machine (made out of matter) built thanks to that understanding. Do you perhaps mean something else?
Sure we can have ideas and possible approaches but just as many scifi authors thought that we would be flying around instead of driving by now, it doesn't have to be the right idea.
My favourite idea is to consider the planet our spaceship and ensuring our existence into the future the technology that we need. It does seem to be the hardest problem to solve currently.
In many cases higher rank humans block innovation because it threatens them. There’d probably be less if that too. Personally I suspect this is one reason it took 300000 years for humans to start building significant technology.
The thing that’s hard to imagine is what the driving force would be without much conflict. Conflict and competitions are easy motivators, at least for us. But a being with a different psychology might have different drives. It doesn’t have to be conflict that motivated growth, just some drive that ties into motivation.
Humans have a natural urge to be inquisitive and make their life's simpler. Obviously if war and conflict were to be the only motivational possibilities, then I do wonder how we made it down from the trees!
A more compelling answer to me is this; civilizations that don't learn how to cooperate at the scale of their planet will destroy or deplete it before they are able to build something of this scale. We have some evidence for this suggestion here on Earth...
> A more compelling answer to me
Agreed, but that's just the usual great filter idea.
It doesn't have to be but with our current mindset, I would agree.
If imagining a cooperative society is hard then it is even harder to imagine the technology that would arise out of such a society.
Edit: for me the open source software movement is a good example of what a cooperative society could do. In 40 years we have gone from room size computers to mobile device that can communicate with anyone on the planet and have access to all the worlds knowledge. This would never have been possible IMO without millions of developers sharing their knowledge.
Grabby Aliens: A Resolution to the Fermi Paradox - https://news.ycombinator.com/item?id=33402628 - Oct 2022 (334 comments)
Grabby Aliens - https://news.ycombinator.com/item?id=26502232 - March 2021 (176 comments)
A Simple Model of Grabby Aliens - https://news.ycombinator.com/item?id=26045731 - Feb 2021 (80 comments)
I don't buy these statistical arguments.
If only one sentient species is born before 20 billion years have passed since the big bang, and ten million sentient species are born after that time, yes - statistically, you're more likely to be one of the later species.
But that early worm species still exists, and experiences its existence.
If they thought to themselves, "obviously there's others out there, it's statistically certain!", then they are wrong.
It's very likely we're not the first in the universe and it's also likely we're not alone in coming to sentience at this very moment in the universes life.
I don't find the argument convincing though (per my other comment)
Sure, but clearly civilizations don't exclusively develop around newly formed stars: we didn't. Most stars are red dwarves and will continue shining for trillions of years.
https://arxiv.org/pdf/2009.11126.pdf
I don't think it's a reasonable assumption that the rate of life (or civilization) formation would remain constant on a planet around a red dwarf over extended periods of time. I don't think Earth could survive for trillions of years as a life bearing planet, even with a more long lived star. Without radioactivity and primordial heat, plate tectonics would cease and the magnetic field would go away. The lack of magnetic field would mean the atmosphere would be lost as well.
https://www.ox.ac.uk/news/science-blog/why-are-we-now
It’s early here, but it think the gist of it is using Bayes to quantify:
Given that the universe would seem to get more hospitable at older ages,
why are we alive now?
IIUC the most likely explanation is some secondary force (aliens) to modify the future hospitality.
That does not seem right. Isn't the lifespan of a star between 100m and 100b years or so?
Sol will grow large and red in another 4×10^9 years or so, then after that phase it’ll leave a stellar remnant like a brown dwarf or neutron star, which will last another period of time. How long did Sol last?
Stopped reading right there.