I have a question... and this is probably a stupid question, but... does anyone know if there is any theory to support the idea that sufficiently advanced civilizations rely on something other than radio waves or light to perform communications? My dumbass-self wonders about quantum entanglement or teleportation as means of communication we have yet to master; may be, the medium of communications for the super civilizations of the universe.
Note: Just wanted to say, I'm less trying to talk about "FTL" and more so that we may just not be able to intercept, decode, or "see" the communications via our current technologies.
It depends on whether you want to stay grounded in real-world physics, or if you want to spin off on flights of fancy.
If you want to stay in real-world physics, at the moment there is no reason to expect any civilization to use anything other than electromagnetic radiation for communication. Other than the low speed of light, which is a characteristic of the universe that it does not seem to allow any faster-than-light communication so it's not specially a disadvantage for EM, electromagnetic radiation basically has every characteristic you're looking for in a communications medium, and there's little reason to believe even an advanced civilization would use something orders of magnitude worse on numerous dimensions simply because maybe they can. This is for much the same reason that we could transport everything in our civilization by people carrying things around on Segways, but we don't, because why would we deliberately choose something suboptimal?
If you want to go off on flights of fancy, then anything is possible, but there's no way to say anything useful about it.
The "grounded in reality" answer is subject to change as our understanding of physics improves, but at the moment I wouldn't say there's any particular reason to expect this answer to change much. Even on the crazy fringe frontiers of real science, I am not aware of any candidates for communication any better than EM.
Most of the whacky ideas proposed as alternate methods fail by orders of magnitude vs EM. Might you be able to build a better neutrino detector than we can? Maybe, but it's still easier to build EM detectors, and EM emitters, by a lot. Gravity waves? Why on not-Earth would anyone spend the massive, massive amounts of energy required to do that, very klunkily and with very low bandwidth, when for literally a trillionth of a trillionth of a trillionth of a trillionth the energy expenditure you could use EM, and get higher bandwidth to boot and better reusability to boot? Quantum entanglement and teleportion are non-starters, because they both require a conventional channel to work at all, and the best tool for that communication is EM.
Even with EM, they could have a highly advanced encoding format which is barely detectable about the random noise floor (spread spectrum like). US army uses these kind of techniques to make the signal both hard to detect and hard to jam.
Who knows how far you can push this, maybe to the point where it's essentially impossible to detect the signal if you are not the intended target.
I think the idea is not whether we could speculate in a useful way about an FTL or otherwise seemingly impossible phenomenon that we are not yet aware of. It's more about the probability that phenomena and technologies that are far beyond our current understanding can exist or not. In all likelihood we would have the intelligence and technology of ants relative to a million year old civilization. We shouldn't limit what is possible in this universe to what ants are able to comprehend and achieve. Even without such an argument, we only need to look at what we thought was possible 500 or 1000 years ago, and extrapolate forward that in all likelihood our currently understood limitations of physics will all but be irrelevant in 1000 years.
Agreed that it's a flight of fancy to speculate on these yet unknown capabilities, but that doesn't mean they aren't highly likely to exist.
This is for much the same reason that we could transport everything in our civilization by people carrying things around on Segways, but we don't, because why would we deliberately choose something suboptimal?
In some high profile military simulation exercises, the "Iran" side used motorcycle couriers to side-step the "US" advantage in signals intelligence. Perhaps other civilizations which manage to survive know something that prompts them to use highly directed, highly efficient spread spectrum technologies which are very hard for us to detect?
Perhaps the universe is much more dangerous for intelligent beings than we know in our youthful naivete as a species?
i feel this is too hyperbolic in the wrong direction. there is clearly more beyond our current knowledge of physics, so why is it beyond the realms of reality to assume that something in that subset of all knowledge is useful? we didn't even know of the possibility of gravitational waves a century ago and just confirmed their existence. so why is it reasonable to say they couldn't possibly be useful for communications?
in dealing with the eventuality of alien civilizations, we must open our mind. it is certainly probable they communicate in ways we can't understand, even if they are simply evolutions of our current communication methods.
I agree with your praise of EM. But hypothetical aliens might want to explore some trade-offs. The game we are playing is to find some advantage in the known physics of a medium even if we know of no practical way to create and detect those signals.
Neutrinos spring to mind: we can't work with them because they don't interact with matter. But if you had some technology that could interact with them, you would have the advantage that nothing in the natural world screens them much.
Even if that technology was much more cumbersome than radio, aliens might have special cases uses for it (e.g. for signalling to and from their secret base at the centre of the Earth).
To me the most straightforward thing to think about is EM waves at frequencies we can only imagine. Very different sources and detectors from what we have, therefore the radiation is undetectable to us (also very line-of-sight), but still the same physics in terms of the properties-of-the-universe required. I would imagine this increase would be developed for the same reason we have gone from KHz to GHz in a hundred-odd years: The higher the frequency the more information you can transmit per second.
Or perhaps we are a only advanced civilization in the known universe and other civilizations are using some lo-tech method of communication like creating sounds or fire signals. Add we are looking for only high-tech modes of communications.
But we didn't suspect EM radiations existed until we started understanding electricity, magnetic fields, etc. What else do we not suspect exists today but will be obvious in 50 years?
How about soliton pulses in a plasma? Isn't interstellar space mostly plasma? Its still EM radiation. Such pulses can survive incredible distances undiminished, and they are point-to-point (not broadcast). So other civilizations might be using this, and we'd never notice unless we got between them and their target by accident
And of course it would be compressed or encrypted or both. So it would be indistinguishable from noise (as mentioned in other replies)
>If you want to go off on flights of fancy, then anything is possible, but there's no way to say anything useful about it.
I would guess, though I could be completely wrong, that a civilization that both had access to far more advanced 'sci-fi' level technology and wanted to broadcast it's existence would also have an understanding of the technology other civilizations would have access to and would choose to broadcast using numerous 'ancient' technologies that more privatize civilizations could pick up on.
When we sent probes out into space to broadcast ourselves, we realized we couldn't just write a message in English and as such tried to send numerous different ways of conveying information, some linguistic and some not.
> Even on the crazy fringe frontiers of real science, I am not aware of any candidates for communication any better than EM.
There is one, and it is essentially
> people carrying things around on Segways
Electromagnetic radiation must obey the inverse square law. It spreads spherically through space, so required power for a given SNR raises with distance squared.
Moreover, there are severe interference issues. Once you have several systems communicating on the same bands you get more noise in the relevant frequency bands.
Unlike waves which don't self-interact (i.e. obey the superposition principle, are linear), matter is coherent. If you shoot a hard drive at a distance galaxy (with greater than escape velocity), it may take significant time to get there, but you can travel arbitrarily far for essentially the same energy, as a first approximation.
Of course, as a second approximation there is necessity of guidance/control (because of finite motor precision, target uncertainty, etc), but also the possibility of harvesting energy or photon momentum from stars en route.
Aside from the expansion of the universe there's no theoretical limit as to why a sufficiently advanced probe couldn't propagate information arbitrarily far (if it "refuels" periodically, then its total energy usage is proportional to distance, i.e. linear, but launch cost stays bounded).
In the worst case (perhaps for cosmically large distances) it'd need to colonize a planet en route to rebuild a pristine copy of itself.
"Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway."
"The only way to actually reach the FedEx point is if transfer rates grow much faster than storage rates. In an intuitive sense, this seems unlikely, since storage and transfer are fundamentally linked—all that data is coming from somewhere and going somewhere (...)"
Wait, why is Quantum Entanglement a non-starter? How does that require a conventional channel? Once you have the two entangled, assuming you have some way to change the state of one with out breaking the entanglement, then how is that not enough for communication?
>which is a characteristic of the universe that it does not seem to allow any faster-than-light communication
Great answer, but do you have more information on this?
I thought quantum entanglement allowed for teleportation of information at faster-than-light speeds. Yes, there is the original information being parcelled and shipped at slower-than-light speeds, but the individual act of disentangling particles can act as a faster-than-light signal.
They could just high focus beams of extremely energetic photons or even gamma ray transmitters with encoding that’s basically “noise” because we grew and evolved around it. There was one theory for Tabby’s star that it was basically a transmission beacon and we happened to see the transmissions because we are in the line of sight.
Take a really weak light source. Aim it at a beam splitter, say, at 45 degrees to the line of the light. Assume that the light source is so weak that typically we get a photon only one a second or so (not strictly necessary for the idea).
Then each photon (there are standard claims that could also use an electron, proton, neutron, etc. but all photons travel at the speed of light, and using just light we don't have to worry about the electric charge of an electron or proton) has a quantum mechanical wave function. From the lessons we get from Young's double slit, the Michelson-Morley experiment, the Mach-Zehnder interferometer, the Fabre-Perot interferometer (right, my ugrad physics prof liked optics!), we believe at the beam splitter the wave function becomes two parts, one part continuing straight through the beam splitter and the other part going off at 90 degrees.
Now sit and have a brewski or two; finish a physics Ph.D.; get married; have a lot of kids; get them all through college; and, I omitted, for the beam that went through the beam splitter, have it bouncing around in a box full of perfect mirrors or resting in some Bose-Einstein condensate, and then get out a very sensitive photo detector and try to detect the photon.
Okay, for a perfect beam splitter, have a 50% chance of detecting the photon. Suppose we do, or, suppose we just in the beginning did this stuff for 1000 individual photons and pick one of the photons where we do get a detection from the part of the wave function close to us (the other half of the wave function is way past the nearest star by now).
So, we get our detection. We know the energy we get, just proportional to the frequency of the light. So, our detector gets it all -- the wavelength, the frequency, the momentum, the energy, maybe the polarization. Fine.
Now, folks, what the heck happens to the other half of the wave function, the half that went 90 degrees and by now is part way out of the galaxy?
No sense in saying that half just disappeared. For one, ET way out there 50% of the time could detect the photon. For another, we could have a mirror out there and have that half of the wave function return to us and do a Young's double slit or Michelson-Morley experiment where both parts of the wave function definitely get involved. So, no saying that the half of the wave function nearly out of the galaxy doesn't matter.
I know; I know; that half of the wave function gets old and tired, goes de-coherent, etc., but such stuff raises other little issues such as conservation of energy. So let's assume that, even after all these years, both parts of the wave function are still nice and healthy just like they would have been in Young's double slit, the Michelson-Morley experiment, etc. Besides we believe we can detect photons 13.8 or so billion years old, and, really, some of those may have their wave functions, from being deflected here and there for all those years, in multiple parts.
But we know also that we and ET can't both detect the photon. So, that part of the wave function out there with ET can't just do its own thing -- with us and ET, there will be exactly one detection.
Okay, when we get the detection, supposedly the other half of the wave function, some light years out there where ET is, disappears, folds up, evaporates, leaves town, becomes null and void, instantly, just as soon as we make our detection. So, sorry guys, that looks like an instantaneous effect (I didn't say communications) over a distance of light years. So, the naughty boy in his room running the simulation for our universe, as soon as we detect the photon, has to run around all over the whole darned universe and clean up any stray pieces of the wave function of the original photon, and there may be thousands of those. During this clean up, the whole simulation (think of a data base problem!) has to stop. So, the simulation has to run all over the universe or a lot of it in zero time -- that's an effect infinitely fast!
I know; I know; this is not faster than light travel for us, but it looks like faster than light travel for the naughty boy's universe simulation program.
Now from this, what can we say about how the quantum fields we believe in actually have to work? Is there something?
E.g., suppose both we and ET have really sensitive gravitational wave detectors and, thus, can detect each of the two pieces of the wave function as they pass by. Uh, the photon has to feel gravity and also create gravity, and, thus, BOTH parts of the wave function have to create gravity. So that part of the wave function that ET gets MUST create a gravitational wave as it passes by and MUST create a gravitational wave as it disappears instantly as we detect the photon. We're getting close to faster than speed of light something or other ...!
Okay, suppose ET is 10 light years away and we want to spend the next 10 years setting up an instantly fast communications channel.
We agree to send one bit a second.
We use the beam splitter, ..., etc. as above.
If we are using our elecgtro-magnetic detector, the for each photon we have not detected, ET gets both a gravitational wave detection and a photon (electro-magnetic) detection.
For each photon we do detect, ET gets neither the gravitational nor the electro-magnetic detection.
If we put our detector in the path of our half of the wave function, then we get a detection half the time which means that half the time ET gets neither a gravitational nor an electro-magnetic detection.
If we do not have our detector in front of our half of the photon, then ET always gets the gravitational signal and half the time gets the electro-magnetic signal.
So, suppose each second (since when we started spending 10 years setting up the communications channel) we sent 1000 photons a second.
Now for one of those seconds, if we are using our electro-magnetic photon detector, ET gets about 500 gravitational wave detections and 500 electro-magnetic detections. If we are not using our photon detector, then ET gets 1000 gravitational wave detections and 500 electro-magnetic detections. So, once we have spent 10 years setting up the communications channel, we can communicate at data rate of 1 bit a second with ET instantly.
I don't really believe it, but first cut it looks that way!
Now each second, we either put our detector in the path of our half of the wave function or we don't.
Staying grounded in current physics is not a good idea. Humans are primitive and other civilizations capable of traveling the solar system is not.
Its like if you would ask a human 500 years ago how he think aliens would travel. He would say something likely in that age according to his understanding. We are exactly the same.
I think the parent meant -- or a least a steelman of the point would be -- whether there could be some kind of particle/field/force/form-of-energy we're missing out on that could be used to communicate (even if slower than light), and whether there's some way to rule that out. I don't think that's dismissable as being a flight of fancy any more than the existence of radio waves would have been in 1500.
> electromagnetic radiation basically has every characteristic you're looking for in a communications medium
Communication by electromagnetic radiation suffers from the fact that the radiation diffuses indiscriminately in all directions. Consider two models of "communication" -- in model 1, messages are sent by lighting a lantern and waiting for the other party to see it, and in model 2, messages are sent by propelling a less wave-like rock into the other party.
Model 1 is faster. But in model 2, my messages don't get broadcast to the entire world as I send them, all the energy I put into sending the message goes into delivering it (whereas most of the energy given off by the lantern is wasted), and if I start throwing rocks at my friend, that will not in general interfere with the rocks thrown between you and your friend.
It's possible that they are using the orbital angular momentum of photons to communicate and we would not have discovered it, because we are not yet listening for it.
If every civilization that invents a radio gets past this phase we are now very fast (as we are soon going to do) advanced civilizations don't bother to encode their messages in a way that we listen now (we look mostly for phase and amplitude encoding)
Photons carry both Orbital Angular Momentum (OAM) and Spin Angular Momentum (SAM) OAM is relatively recent discovery (1990's). They exist just not in the light beams level but also at the single-photon level (very surprising).
Definitely not a stupid question, just the wrong question IMO. The real question would be do we have any reason to believe that they do still use radio?
We've had radio for just a little over 200 years and we've already realized its limitations. The fact that we can even speculate about quantum communication leads me to believe that radio is definitely NOT the end-all-be-all. If you scale human civilization into a 1 year time frame we invent radio at 3PM on December 31st. It's successor likely emerges January 2nd at the latest. Radio communication is likely a blip.
Radio is efficient over short terrestrial distance but horrible for long (galaxy scale) distance communication. If interstellar travel is feasible at all it will have to be at FTL speeds and an FTL communication system would be necessary.
If FTL is truly impossible then it doesn't seem like there is much point in listening since everything is so incredibly far it's irrelevant even on a species-level or planetary-level time scale. I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources.
> The fact that we can even speculate about quantum communication leads me to believe that radio is definitely NOT the end-all-be-all
Who is it that's speculating about quantum communication? Certainly not physicists. It's mostly just IFLScience!-class journalists seeing a term like "quantum teleportation" and assuming that it means start trek is real and write their articles based on that.
> I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources.
If everyone at SETI believes that mysterious FTL communication exists, then why do they spend all their time looking for EM signals?
>"If interstellar travel is feasible at all it will have to be at FTL speed"
Why is that? Special relativity already demonstrates that space contraction at near light speed would allow interstellar travel at human scale duration, with the side effect of time dilation for moving observers.
If FTL is truly impossible then it doesn't seem like there is much point in listening since everything is so incredibly far it's irrelevant even on a species-level or planetary-level time scale.
Probably true on a species level, but you are vastly underestimating how long a planetary-level timescale is. A von Neumann probe could cover the entire Milky Way in relatively short geological time.
I don't know if we count as advanced, but our communications are moving towards light that's confined to fiber optic cables, and radio waves that are practically disguised as noise. We are making an ongoing effort to reduce the power level used by those communications. That doesn't seem promising for having someone detect us from a distance.
For inter-stellar communications of sufficient distance, some sort of massive object (i.e., a space ship) seems like the preferred method because it can go at almost the speed of light, but it doesn't spread out over distance, can make minor corrections to its course, visit multiple destinations, and do something such as return a message, learn about its surroundings, and so forth.
I'd guess that a civilization might go through a period where it is emitting lots of easy-to-detect radio signals, lasting maybe a century, so we have to catch them at just the right moment.
SETI more expects side-effect radio emissions than purposeful communications. It was started at a time when powerful radars [1] designed to detect ballistic missiles were deployed and this radar's emissions are definitely detectable several light-years away.
It relies on the same mentality as the Fermi Paradox: it expects that an advanced civilization will master so much energy that its waste should be visible from afar. Only recently have we started considering that efficiency, rather than wastefulness, may be the hallmarks of civilization.
But yes, everybody at SETI knows that what they are doing are stabs in the dark. It is like trying to find inhabited lands by looking for tam-tam songs along the coast or to check if there are lighthouses installed where people may have switched to GPS.
Still, if there are thousands of civilizations out there, you can bet on off-chances of detecting one. The odds are low but the rewards would be huge. Fewer discoveries would be as consequential as this one.
I always liked the theory that if you go stand above an ant hill and scream all day at the little creatures, they'll still have no concept of your attempts at communication.
So then similarly, it seems possible that advanced intelligence could be screaming at us but we're too "simple" to be able to understand them or even be aware of their presence.
The bit that saddens me is the realisation that those ants will probably find "aliens" one day, the termite mound half a mile away, and likely fight terrible wars, but even if not, neither side will ever see sunrise over central park
EM waves are, given everything we know about the universe, the obvious communication medium for advanced civilizations no matter where or who they are. Maybe somebody sufficiently indistinguishable from a god could use gravitational waves, but off the top of my head I'm not sure why you'd want to bother.
Quantum entanglement does not, as far as we know, enable superluminal transmission of information. "Teleportation" is implementation-dependent and at this point entirely science fiction. If you're going to rip something apart or non-destructively scan it, and rebuild it at the other end, which is the only "realistic" theory of how it might work, you either need to transmit the bits or the bits (heh) and then you're back to the same problem of information transmission.
Of course we don't know everything, but the discussion really ends there: we don't know what we don't know.
Sure but imagine what someone would have said before we discovered radio waves.
We don’t know that there is anything better, but given how much we don’t know it’s not unreasonable to consider that we might not have the technology to receive communications from more advanced civilizations.
I agree with you that RF is a good communication medium given what we know, I just don’t put much weight on our existing knowledge being all there is.
does anyone know if there is any theory to support the idea that sufficiently advanced civilizations rely on something other than radio waves or light to perform communications?
This implies a common assumption among people: That any civilization out there is automatically going to be more advanced than we are.
If you believe that the universe started with the Big Bang, then (IMO), it's reasonable to believe that we all had pretty much the same amount of time to evolve and develop civilizations. Asteroid events notwithstanding.
To me, believing that all beings average about the same place in the development cycle, it makes sense to look for the signals we know, rather than the signals we don't know.
In 500 years we've gone from signalling towers to lasers, fiber and RF. If someone got a 10,000 year jump on us and has a technological improvement rate close to us, we don't know the scale, frequency, or means of communication. There's a lot of physics we know, but there's also more we don't know.
Also, I can't use language bi directionally with a plant no matter how hard I try. Maybe we're the plants. Maybe they don't have language.
The universe is about 14bn years old.
Earth is about 4.5bn years old.
Humans are about 100k years old.
Writing is about 5k years old.
Radio communication is about 150 years old.
The laser is about 50 years old.
So that window holding our current level of communication abilities is 0.15% to 0.05% of our species' age, and our species is in a similarly tiny window.
I ain't no astrologist either, but there's also an assumption other beings would have similar biology to us, it seems.
To the side now with assumption they might communicate chemically only between themselves... WHAT IF their clock rate is way slower than ours? Like snails, or plants. Their bitrate of communication would be undetectable to us, if they're way slower. I suspect it would be detectable if their rate is higher though.
There's a great short story by Harry Turtledove called "The Road Not Taken" that tries to jostle that view. If you can find a copy of it, worth a read.
Even if a sufficiently advanced civ out there is using something like quantum entanglement, they mostly likely didn't just jump from smoke signals to quantum entanglement. So we might be catching signals from the say 500 years while they used radio waves.
Look at us as an example though. We've had radio for a little over 200 years and already realize its limitations.
Smoke signals will have been around for a lot longer than radio. Smoke signals will have been around for 99.9% of the timeline and then 0.1% radio before quantum. To an outside observer it would look like radio was just skipped.
If you scale human civilization into a 1 year time frame we invent radio at 3PM on December 31st.
Assuming that we are right that matter can't 'travel' FTL, it's entirely possible that signals can (despite our current inability to understand how) somehow travel FTL. Once discovered, that method might be a thousand or million times FTL.
Such a relatively instant means of communication would become the defacto standard. Antiquated EM methods and equipment would be forgotten. Noone would be listening for it, just as very few today would recognize semaphore flags, smoke signals, or telegraph codes.
Today we'd not be eligible to join that club. And if we choose to remain certain that it doesn't exist, our determined ignorance would keep us locked out. If we conclude that we aren't special, that there -must- be life elsewhere, then the only logical thing to do is to keep our minds open and keep looking for clues.
We can't ever decide that we know enough. A century ago, the Milky Way was the whole universe. A few more observations changed that forever.
Just so you know, entanglement can't be used to transmit data. You must still transport the particles which have become entangled. When you observe them later you are only "instantaneously obtaining information" through the process of elimination.
But isn't there a certain probability we missed those radio waves back when we didn't know radio and now the earth is receiving more sophisticated signals humans can't yet analyze?
You'll want to read "The Eerie Silence" by SETI lead Paul Davies who's job is to think of this stuff.
The book covers many many possibilities for how a civilization might try to communicate or get the word out from Von Neumann probes to leaving something in our DNA, which could easily last multiple millennia to monuments...etc etc. It also covers the search for life elsewhere like looking for reverse chirality DNA on Mars (basically there is no reason all DNA found on earth should curl one way and finding DNA that goes the other way strongly suggests it didn't come from us).
Despite the fact that quantum entanglement is frequently referred to the new ways of communication, at the current state of Standard model/Quantum physics quantum entanglement does not mean interaction or information transfer. Furthermore, instantaneous information transfer is restricted and its speed is limited to the speed of light.
Quantum entanglement is rather about correlation and statistics, which is, hopefully, will be quite useful for some applications, but not for communication channel. Otherwise, it will ruin the current foundation of quantum mechanics.
I strongly recommend reading the book of Nicolas Gisin 'Quantum Chance' [1], which is quite good for the general audience to understand, what quantum entanglement actually means in the real life, i.e. in the physical experiment.
Or they use EM but are allot more efficient with communication such that they don't leak.
These SETI signals, if they were of intelligent origin, would be showing just how dumb these aliens are. To send a presumably fairly local signal in such a way that it wastes such vast amounts of energy that it can be picked up 3bil ly away would seem like a serious transmitter design flaw.
Why? Literally the cheapest thing to use acrossm interstellar distance is your local star in the cosmic equivalent of flashing in Morse code.
Say you want to communicate between 2 star systems all you need to do is to position say a polarizer between at the edge of each solar system such as that polarizer can obstruct a suffiently large portion of the star from the point of view of the system you want to communicate at say the edge of a solar system it won’t even have to be that big.
You use the polarizer to modulate the passing light and encode your message onto it.
Gravitational waves could be a prime candidate. Assuming that you have enough power to create one it could travel to the other side of the universe without any kind of interference. Whether you can embed a message in them is a whole different story though, we couldn't possibly know with our current understanding.
The concept is used in the "The Three Body" trilogy.
But surely an advanced civilization would realize theres less advanced lifeforms and would thus send the simplest type of message possible. After contact is established, they could then send their ultra-compressed data.
"I am old, older than thought in your species, which is itself fifty times older than your history. Though I have been on earth for ages I am from the stars. My home is no one planet, for many worlds scattered through the shining disc of the galaxy have conditions which allow my spores an opportunity for life. The mushroom which you see is the part of my body given to sex thrills and sun bathing, my true body is a fine network of fibers growing through the soil. These networks may cover acres and may have far more connections that the number in a human brain. My mycelial network is nearly immortal, only the sudden toxification of a planet or the explosion of its parent star can wipe me out. By means impossible to explain because of certain misconceptions in your model of reality all my mycelial networks in the galaxy are in hyperlight communication across space and time. The mycelial body is as fragile as a spider's web but the collective hypermind and memory is a vast historical archive of the career of evolving intelligence on many worlds in our spiral star swarm. Space, you see, is a vast ocean to those hardy life forms that have the ability to reproduce from spores, for spores are covered with the hardest organic substance known."
> I have a question... and this is probably a stupid question, but... does anyone know if there is any theory to support the idea that sufficiently advanced civilizations rely on something other than radio waves or light to perform communications?
This probably really should be five questions.
1. For an advanced civilization trying to communicate to other, unknown, civilizations like ours. In other words, intentionally trying to have our SETI folks notice them.
2. Similar, but trying to communicate with a civilization that their SETI folks have detected. E.g., they have picked up on our existence from our EM emissions and want to to strike up a conversation.
3. For an advanced civilization that spans multiple star systems, not intentionally trying to communicate with anyone else.
4. Similar, but only spanning multiple planets within one system.
5. Finally, for an advanced civilization that is only one planet, not trying to communicate with anyone else.
For #1-4, EM is the most likely answer for reasons numerous others have mentioned. For #3 and #4, the big issue would be power. If they are only intending internal communication they might not be putting enough power for us to pick it up unless they are close to us.
For #5, even if they have not discovered something beyond the physics we know, they might not radiate their EM in a way we can detect. For example, if they have a planet wide urban civilization they might have every building connected to a high speed wired communication system. The only wireless they use might be something like Bluetooth or low power WiFi that only needs to communicate within a single room of a building between their portable devices and that room's node on the wired system.
Another interesting question is if they are EM radiation.
It should be the most efficient way to travel. Going from Turing machine to Turing machine, a virus with a really advanced universal exploit, impregnating civilizations like ours around the time they develop both radio tech and computers.
Civilizations with the capability to travel in that fasion would be dominant.
>does anyone know if there is any theory to support the idea that sufficiently advanced civilizations rely on something other than radio waves or light to perform communications?
At a scienctific level no, but in science fiction you have devices like the 'subspace ansible' and similar things that allow FTL communications by using some sort of currently-undiscovered 'subspace'.
I actually remember in the mid 90's seeing, in the Weekly World News (a sensational tabloid for those unfamiliar) or its primary competitor at the time, mention of a intelligence agency that had laptop like devices that allowed for real-time encrypted communication anywhere on the world which was likely a spin on this idea (IIRC it was suggesting some sort of quantum entanglement where doing something to one would instantly cause the same to happen on the 'paired' device so you'd just type on one and it would instantly appear on the display of the other).
There's no valid reason to think something like this isn't possible, or even plausible. We didn't discover infrared until 1800, x-rays and radio until 1895.
There could very well NOT be anything that would allow for FTL/real-time communication over any distance but then again there could be. There could very well be some sort of radiation or similar particle that we've yet to discover too which might be the preferred means of communication for an advanced enough civilization.
Look how far computers have come since I was born in 1985. Look at other technologies like genome sequencing, the human genome project took 13 years and cost many millions but now you can do whole genome sequencing commercially with an 18 hour turnaround and hire your own whole genome sequencing out for 500$ with a 10-12 week turnaround. I know these examples don't compare but what I'm getting at is we are barely a technological species and who knows what possibilities exist for us.
I mean, before we knew that radio waves exists we could not forsee the use of radio for communicating
so, I'd say that better ways of communicating relay on something that physics hasn't found yet (like, you know "that weird supersimmetry decay thing that only su-top quarks do when reacting with Stuff")
I think others have it right, with what we know EM is the way to go. But I keep thinking about dark matter and dark energy and how we don’t understand them. It wasn’t really that long ago that we didn’t understand EM either. Finding radio waves was exactly like finding invisible ways to communicate. Who knows what we can’t “see” yet.
I think this goes back to searching for other life on earth-like planets. We know what life looks like on our planet, so that's really the only thing we have to go off of, otherwise we are stabbing in the dark.
Likely we are searching for radio waves and light since that's the only thing we know how to communicate with.
It is more than that. We know what life looks like: composed of carbon because that is the only atom than easily forms long chains of double bonds. It is also very likely to be composed of the atoms that are common in the universe: the low Atomic number ones.
If they're super smart, and actually care about communicating with less-advanced civilizations, then they would probably broadcast through mediums that are considered "old tech" for them, but possibly current tech for those civilizations.
Humans aren't broadcasting into space with any pre-EM technologies. It's not so much that we don't care about less-advanced civilizations, but that broadcasting in a way that life forms could see/hear without electronic sensors would be many orders of magnitude less efficient for us. It's simply impractical.
Maybe there's another form of communication we haven't discovered yet that's so much faster and more efficient (like Star Trek's "subspace") that everybody else in the galaxy uses that instead. For them to send radio waves to Earth might be like us pointing Morse lamps at Alpha Centauri.
Trying to detect alien life by scanning the EM spectrum sure is inefficient. Maybe it's the best we can do, but if there were something better, I could totally see why we'd abandon plain old radio waves.
Personally I think the assumption that science has figured it out is going to turn out to be nonsense. Science thought that in the nineteenth century right before discovery of general relativity and quantum mechanics.
Personally until we've figured out things like consiousness and dark matter/inflation etc I think the null hypothesis should be that there is unexplained stuff happening and thus it's likely advanced civilizations use something other than electromagnetic waves, just like we don't use smoke signals or fire beacons much for communication anymore.
Very advanced civilizations could learn how to create targeted worm hole like structures to send information through it using real world physic rules that we don't know yet
I always believed that all that SETI thing will be pretty silly if in few hundred years we'll discover how to emit and receive neutrino beams for communication.
SETI would become search for extraterrestrial intelligence that that believes it's worth a shot to emit RF to contact less advanced civilisations that at the moment of recieving the signal will be in that small time window when they used RF for communication because they had nothing better.
We don't have much of an option but to look with the tools we have, so though it's an interesting thought exercise (and continually worth pushing for new sciences) I don't think it's actionable to assume otherwise. E.g. I don't know of any generally-accepted theory that says that sufficiently advanced civs will definitely not use what we use, so it's still worth looking while we try to discover new things :)
I think the people who downplay this question forget that many technologies we take for granted today would be considered impossible by older understandings of physics.
What if alien civilisations figured it was a good move to hide themselves from hostile civilisations... Or if those that broadcast like we do were destroyed by hostile civilizations. Let's hope not I guess.
EM is quite disappointingly weak for anything except point to point communications. If you really wanted to broadcast a message, it'd be far better to use something like von-neumann probes.
I mean, of course we might be missing out on things we can't technologically grasp yet... but even if we knew it existed we wouldn't know what to do with it yet.
For anyone interested in this or related topics I highly, highly recommend the series of 100+ videos in Science and Futurism with Isaac Arthur ("SFIA") [1].
Relevant to this topic:
- Fermi Paradox series (15 videos) [2]
- Advanced Civilizations (19 videos) [3]
- Alien Civilizations (10 videos) [4]
Of particular relevance is the Kardashev scale [5]. The basic idea is this: unless something catastrophic happens, humanity is destined to become a Kardashev-2 ("K2") civilization without a blink of a cosmic eye (measured in thousands of years). Since the timeline from sentience to K2 is so short (cosmologically speaking) it seems pretty unlikely there are other spacefaring civilizations in our galaxy.
It's worth noting that the scale of such a civilization is so immense and what it is capable of with access to that much energy and resources tends to debunk a lot of ideas that come out of a search for explanations to the Fermi paradox.
For example, there is the idea that civilizations might "hide" and would not be detectable. Such an effort would be futile vs a K2 civilization however.
I mention this because there is the idea that aliens might not use radio technology. Doing so wouldn't keep you hidden from a K2 civilization so there's no point in trying. And I find this a compelling line of reasoning.
One problem with things like this is the arrogance of the present. We had no idea that electromagnetic energy even existed until the later half of the 19th century. Even though it had been observed for centuries that lightning strikes could screw with a compass needle, we somehow never managed to put two and two together. Kind of funny in hindsight. Consequently all of our predictions for the future were cast through this lens. So their ideas of futurism was limited to things such as undersea exploration, flying machines, and ideas like covering an entire city in a roof so you wouldn't get wet while walking about.
Now we take electromagnetism for granted and can observe it everywhere, as it has always been. Yet the problem with this is that now, in order to have any meaningful discussion of the things of which you're speaking, you have to make the very questionable assumption that there will no longer be similarly revolutionary forces we will discover in the future. And so there comes a question of weighting that. What are the odds of that being true?
Our species' entire basis of knowledge is formed, almost exclusively, around observations based on one planet, in one solar system, in one galaxy. Everything else is just reasoning based on incredibly coarse observations of everything else. I think the idea that that we're even remotely close to unlocking the true nature of our universe is not really logical by any measurement other than 'well we're trying really hard and haven't been able to make that next step yet' which has, of course, been true throughout our species entire existence -- until that next step is invariably made. The increasing difficulty does not indicate anything like evidence of approaching an end to revolutionary discovery itself. Yet if we're not at the end then any meaningful big picture or very long term predictions are going to serve as little more than the butt of jokes for those with the opportunity to read such predictions from the future.
The point use that we don't need to assume any new physics or assume any new technology beyond what is considered highly likely for the next century to view Dyson spheres as admission inevitable. We don't even need to assume fusion.
New technologies exacerbate this problem rather than solve it. As do new physics. In fact Isaac mentioned multiple times that the inability the apparent absence of evidence of advanced civilizations is the best evidence for there not being FTL travel or communication (as just one example).
So while i can agree we don't know everything I'm not sure why it matters.
I made this comment earlier but to me the most logical explanation to the Fermi paradox is the vast amount of time between existence of any 2 civilizations. While many could in theory exist in the same Galaxy, the cosmic scale makes it unlikely that any two will ever share the same time scale, thus making any possibility of contact unlikely.
You've gotta keep relativity in mind here. If a species can develop a means of simply traveling at roughly 1g acceleration indefinitely, they will become -in terms of time- practically immortal. A single human can travel literally billions of light years in a single lifetime by continuing to accelerate at 1g for years at a time. Here [1] is a calculator to determine how long it would take to travel a given distance at a given acceleration. A common misunderstanding is the difference between observed mass increases and perceived. Your mass does not increase as you approach the speed of light relative to something else. But your observed mass does.
Anyhow, the point here is that once a species reaches this level of technology, if it's possible, they will start to move beyond anything like the borders of time as we understand them.
In my opinion, the most simple and probable explanation is technology (we don't know what's out there), but that's closely followed by the terrifying great filter being complete and unadulterated pleasure. As lives become easier and more pleasurable, the inherent drive towards procreation becomes less and less of a factor. If that reaches below a certain point, that's lights out for a species. Create a guaranteed means of subsistence on a planet, perhaps entirely automated, and now create a technology that becomes more inherently enjoyable and rewarding than procreation itself. Congrats you evil villain, you've destroyed your species in a far more effective way than any weapon ever could. Society goes out not with a bang, but also not with a whimper; they go out with a moan of pleasure.
So this is several theories wrapped into one. The Dyson Dilemma (meaning Dyson spheres seem inevitable for civilizations with no more tech than we’re expected to have this century) reduces this idea to civilizations tend to destroy themselves.
It’s important to remember that we are not arguing if some if not many or even most civilizations destroy themselves. For this to explain the Fermi Paradox you’re arguing that basically all do and there are lots of problems with that argument.
Dyson spheres are not subtle. We can say a high degree of certa8nty that no Dyson spheres have emerged within a billion or so light years of us where light has had time to reach us or we would’ve detected them.
Say 10,000 civilizations rose up within that sphere. Even if 9,999 of them destroyed themselves we would detect that 1 tha didn’t.
The argument against this is that a civilization that colonises more than two planets(which a K2 civ could do) has astronomically low chances of getting wiped out, so any that get there first should probably still exist. Which means the time gulf isn't really the problem.
I remember running SETI @ Home on my 300 MHz Gateway and watching the pretty graphs as if I was a real life alien spaceship pilot. It's funny to hear that it's actually a real thing (I knew it was real, but when I saw the size of the radio dish in the image, it's REALLY real)
> I don't think its particularly associated with SETI.
That depends on what you mean by "associated". It's not associated directly with SETI the institute, but it was the site of the first systematic/scientific search (and false positive) for extra-terrestrial intelligence lead by Frank Drake. It is also the place where The Order of the Dolphin (Drake, Carl Sagan, Otto Struve, et al.) met and developed the Drake Equation.
The telescope there is amazing. It's worth a visit, they have a visitor's center and tours. I was there for the 50th anniversary celebration, in 2006, and want to go back some day.
Same on my 100 MHz Apricot. I like to think it helped. One thing that used to bug me is I wondered how much CPU time was being spent on rendering those graphs locally.
> The high degree of rotation of the nearly 100 percent polarized radio bursts is unusual, and has only been seen in radio emissions from the extreme magnetic environments around massive black holes, such as those at the centers of galaxies. The Dutch and Breakthrough Listen teams suggest that the fast radio bursts may come from a highly magnetized rotating neutron star – a magnetar – in the vicinity of a massive black hole that is still growing as gas and dust fall into it.
The short bursts, which range from 30 microseconds to 9 milliseconds in duration, indicate that the source could be as small as 10 kilometers across – the typical size of a neutron star.
Other possible sources are a magnetar interacting with the nebula of material shed when the original star exploded to produce the magnetar; or interactions with the highly magnetized wind from a rotating neutron star, or pulsar.
[0]
Do any terrestrial sources create polarized radio waves? Would polarization help beamforming or other range-extending techniques?
I'm certainly no expert, but the Wikipedia article on the subject says this:
> All radio (and microwave) antennas used for transmitting or receiving are intrinsically polarized. They transmit in (or receive signals from) a particular polarization, being totally insensitive to the opposite polarization; in certain cases that polarization is a function of direction. Most antennas are nominally linearly polarized, but elliptical and circular polarization is a possibility. As is the convention in optics, the "polarization" of a radio wave is understood to refer to the polarization of its electric field, with the magnetic field being at a 90 degree rotation with respect to it for a linearly polarized wave.
I've converted series of those images to audio, it's obviously swipes and trills only. I wish I could get my hands on higher resolution images to get a drop of a real alien dubstep, not some cheap microwave oven blues.
>For instance, the probes picked up the interaction of solar wind on the planets magnetospheres, which releases ionic particles with an audible vibration frequency. Essentially, we can then translate these waves into sound waves and put them on an album.
no way would an Alien specie able of sending signals of such strength would send uncompressed / unpreprocessed audio. it is more likely that they would send perfectly compressed data that would appear indistinguishable from noise to us, as this is what optimally compressed information looks like
It is exciting because we can't explain it yet. That makes it interesting and worthy of study.
>> This could be huge!
Don't get me wrong, I appreciate the humor and understand how the media tends to over hype any news that could potentially excite people interested in the discovery of little green men, but I never felt that this particular article was doing that.
I felt like this particular article was almost bizarrely moderate in its tone. It managed to talk about ML and a new seti discovery in a balanced manner, discussing both the optimistic and realistic takes. I guess I'm just so used to modern headline writing that I'm pleasantly surprised when someone doesn't publish "Artificial Intelligence finds aliens." :)
Ok, but the point isn't little green men -- it's that SETI is now using AI and a convolutional neural network. Not that AI and ML isn't also a victim of media hype...
Readit News
Note: Just wanted to say, I'm less trying to talk about "FTL" and more so that we may just not be able to intercept, decode, or "see" the communications via our current technologies.
P.S. Thanks for the thoughtful replies.
If you want to stay in real-world physics, at the moment there is no reason to expect any civilization to use anything other than electromagnetic radiation for communication. Other than the low speed of light, which is a characteristic of the universe that it does not seem to allow any faster-than-light communication so it's not specially a disadvantage for EM, electromagnetic radiation basically has every characteristic you're looking for in a communications medium, and there's little reason to believe even an advanced civilization would use something orders of magnitude worse on numerous dimensions simply because maybe they can. This is for much the same reason that we could transport everything in our civilization by people carrying things around on Segways, but we don't, because why would we deliberately choose something suboptimal?
If you want to go off on flights of fancy, then anything is possible, but there's no way to say anything useful about it.
The "grounded in reality" answer is subject to change as our understanding of physics improves, but at the moment I wouldn't say there's any particular reason to expect this answer to change much. Even on the crazy fringe frontiers of real science, I am not aware of any candidates for communication any better than EM.
Most of the whacky ideas proposed as alternate methods fail by orders of magnitude vs EM. Might you be able to build a better neutrino detector than we can? Maybe, but it's still easier to build EM detectors, and EM emitters, by a lot. Gravity waves? Why on not-Earth would anyone spend the massive, massive amounts of energy required to do that, very klunkily and with very low bandwidth, when for literally a trillionth of a trillionth of a trillionth of a trillionth the energy expenditure you could use EM, and get higher bandwidth to boot and better reusability to boot? Quantum entanglement and teleportion are non-starters, because they both require a conventional channel to work at all, and the best tool for that communication is EM.
Who knows how far you can push this, maybe to the point where it's essentially impossible to detect the signal if you are not the intended target.
Agreed that it's a flight of fancy to speculate on these yet unknown capabilities, but that doesn't mean they aren't highly likely to exist.
In some high profile military simulation exercises, the "Iran" side used motorcycle couriers to side-step the "US" advantage in signals intelligence. Perhaps other civilizations which manage to survive know something that prompts them to use highly directed, highly efficient spread spectrum technologies which are very hard for us to detect?
Perhaps the universe is much more dangerous for intelligent beings than we know in our youthful naivete as a species?
in dealing with the eventuality of alien civilizations, we must open our mind. it is certainly probable they communicate in ways we can't understand, even if they are simply evolutions of our current communication methods.
Neutrinos spring to mind: we can't work with them because they don't interact with matter. But if you had some technology that could interact with them, you would have the advantage that nothing in the natural world screens them much.
Even if that technology was much more cumbersome than radio, aliens might have special cases uses for it (e.g. for signalling to and from their secret base at the centre of the Earth).
And of course it would be compressed or encrypted or both. So it would be indistinguishable from noise (as mentioned in other replies)
We don’t have an easy way to detect them but a more advanced civilization might.
It seems presumptuous to dismiss the entirety of non-Standard Model physics thusly. Axions [1] are one of my personal favourites.
[1] https://en.m.wikipedia.org/wiki/Axion
I would guess, though I could be completely wrong, that a civilization that both had access to far more advanced 'sci-fi' level technology and wanted to broadcast it's existence would also have an understanding of the technology other civilizations would have access to and would choose to broadcast using numerous 'ancient' technologies that more privatize civilizations could pick up on.
When we sent probes out into space to broadcast ourselves, we realized we couldn't just write a message in English and as such tried to send numerous different ways of conveying information, some linguistic and some not.
There is one, and it is essentially
> people carrying things around on Segways
Electromagnetic radiation must obey the inverse square law. It spreads spherically through space, so required power for a given SNR raises with distance squared.
Moreover, there are severe interference issues. Once you have several systems communicating on the same bands you get more noise in the relevant frequency bands.
Unlike waves which don't self-interact (i.e. obey the superposition principle, are linear), matter is coherent. If you shoot a hard drive at a distance galaxy (with greater than escape velocity), it may take significant time to get there, but you can travel arbitrarily far for essentially the same energy, as a first approximation.
Of course, as a second approximation there is necessity of guidance/control (because of finite motor precision, target uncertainty, etc), but also the possibility of harvesting energy or photon momentum from stars en route.
Aside from the expansion of the universe there's no theoretical limit as to why a sufficiently advanced probe couldn't propagate information arbitrarily far (if it "refuels" periodically, then its total energy usage is proportional to distance, i.e. linear, but launch cost stays bounded).
In the worst case (perhaps for cosmically large distances) it'd need to colonize a planet en route to rebuild a pristine copy of itself.
"Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway."
–Andrew Tanenbaum, 1981
https://what-if.xkcd.com/31/
"The only way to actually reach the FedEx point is if transfer rates grow much faster than storage rates. In an intuitive sense, this seems unlikely, since storage and transfer are fundamentally linked—all that data is coming from somewhere and going somewhere (...)"
https://en.wikipedia.org/wiki/Sneakernet
Great answer, but do you have more information on this?
I thought quantum entanglement allowed for teleportation of information at faster-than-light speeds. Yes, there is the original information being parcelled and shipped at slower-than-light speeds, but the individual act of disentangling particles can act as a faster-than-light signal.
It's easier to build paperclip factories than iphone factories but we are awash in both and some people own more iphones than paperclips.
Why on earth would you build EM emmiter if by bit more effort you could have device for unobstructible communication?
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Take a really weak light source. Aim it at a beam splitter, say, at 45 degrees to the line of the light. Assume that the light source is so weak that typically we get a photon only one a second or so (not strictly necessary for the idea).
Then each photon (there are standard claims that could also use an electron, proton, neutron, etc. but all photons travel at the speed of light, and using just light we don't have to worry about the electric charge of an electron or proton) has a quantum mechanical wave function. From the lessons we get from Young's double slit, the Michelson-Morley experiment, the Mach-Zehnder interferometer, the Fabre-Perot interferometer (right, my ugrad physics prof liked optics!), we believe at the beam splitter the wave function becomes two parts, one part continuing straight through the beam splitter and the other part going off at 90 degrees.
Now sit and have a brewski or two; finish a physics Ph.D.; get married; have a lot of kids; get them all through college; and, I omitted, for the beam that went through the beam splitter, have it bouncing around in a box full of perfect mirrors or resting in some Bose-Einstein condensate, and then get out a very sensitive photo detector and try to detect the photon.
Okay, for a perfect beam splitter, have a 50% chance of detecting the photon. Suppose we do, or, suppose we just in the beginning did this stuff for 1000 individual photons and pick one of the photons where we do get a detection from the part of the wave function close to us (the other half of the wave function is way past the nearest star by now).
So, we get our detection. We know the energy we get, just proportional to the frequency of the light. So, our detector gets it all -- the wavelength, the frequency, the momentum, the energy, maybe the polarization. Fine.
Now, folks, what the heck happens to the other half of the wave function, the half that went 90 degrees and by now is part way out of the galaxy?
No sense in saying that half just disappeared. For one, ET way out there 50% of the time could detect the photon. For another, we could have a mirror out there and have that half of the wave function return to us and do a Young's double slit or Michelson-Morley experiment where both parts of the wave function definitely get involved. So, no saying that the half of the wave function nearly out of the galaxy doesn't matter.
I know; I know; that half of the wave function gets old and tired, goes de-coherent, etc., but such stuff raises other little issues such as conservation of energy. So let's assume that, even after all these years, both parts of the wave function are still nice and healthy just like they would have been in Young's double slit, the Michelson-Morley experiment, etc. Besides we believe we can detect photons 13.8 or so billion years old, and, really, some of those may have their wave functions, from being deflected here and there for all those years, in multiple parts.
But we know also that we and ET can't both detect the photon. So, that part of the wave function out there with ET can't just do its own thing -- with us and ET, there will be exactly one detection.
Okay, when we get the detection, supposedly the other half of the wave function, some light years out there where ET is, disappears, folds up, evaporates, leaves town, becomes null and void, instantly, just as soon as we make our detection. So, sorry guys, that looks like an instantaneous effect (I didn't say communications) over a distance of light years. So, the naughty boy in his room running the simulation for our universe, as soon as we detect the photon, has to run around all over the whole darned universe and clean up any stray pieces of the wave function of the original photon, and there may be thousands of those. During this clean up, the whole simulation (think of a data base problem!) has to stop. So, the simulation has to run all over the universe or a lot of it in zero time -- that's an effect infinitely fast!
I know; I know; this is not faster than light travel for us, but it looks like faster than light travel for the naughty boy's universe simulation program.
Now from this, what can we say about how the quantum fields we believe in actually have to work? Is there something?
E.g., suppose both we and ET have really sensitive gravitational wave detectors and, thus, can detect each of the two pieces of the wave function as they pass by. Uh, the photon has to feel gravity and also create gravity, and, thus, BOTH parts of the wave function have to create gravity. So that part of the wave function that ET gets MUST create a gravitational wave as it passes by and MUST create a gravitational wave as it disappears instantly as we detect the photon. We're getting close to faster than speed of light something or other ...!
Okay, suppose ET is 10 light years away and we want to spend the next 10 years setting up an instantly fast communications channel.
We agree to send one bit a second.
We use the beam splitter, ..., etc. as above.
If we are using our elecgtro-magnetic detector, the for each photon we have not detected, ET gets both a gravitational wave detection and a photon (electro-magnetic) detection.
For each photon we do detect, ET gets neither the gravitational nor the electro-magnetic detection.
If we put our detector in the path of our half of the wave function, then we get a detection half the time which means that half the time ET gets neither a gravitational nor an electro-magnetic detection.
If we do not have our detector in front of our half of the photon, then ET always gets the gravitational signal and half the time gets the electro-magnetic signal.
So, suppose each second (since when we started spending 10 years setting up the communications channel) we sent 1000 photons a second.
Now for one of those seconds, if we are using our electro-magnetic photon detector, ET gets about 500 gravitational wave detections and 500 electro-magnetic detections. If we are not using our photon detector, then ET gets 1000 gravitational wave detections and 500 electro-magnetic detections. So, once we have spent 10 years setting up the communications channel, we can communicate at data rate of 1 bit a second with ET instantly.
I don't really believe it, but first cut it looks that way!
Now each second, we either put our detector in the path of our half of the wave function or we don't.
Its like if you would ask a human 500 years ago how he think aliens would travel. He would say something likely in that age according to his understanding. We are exactly the same.
Communication by electromagnetic radiation suffers from the fact that the radiation diffuses indiscriminately in all directions. Consider two models of "communication" -- in model 1, messages are sent by lighting a lantern and waiting for the other party to see it, and in model 2, messages are sent by propelling a less wave-like rock into the other party.
Model 1 is faster. But in model 2, my messages don't get broadcast to the entire world as I send them, all the energy I put into sending the message goes into delivering it (whereas most of the energy given off by the lantern is wasted), and if I start throwing rocks at my friend, that will not in general interfere with the rocks thrown between you and your friend.
If every civilization that invents a radio gets past this phase we are now very fast (as we are soon going to do) advanced civilizations don't bother to encode their messages in a way that we listen now (we look mostly for phase and amplitude encoding)
Photons carry both Orbital Angular Momentum (OAM) and Spin Angular Momentum (SAM) OAM is relatively recent discovery (1990's). They exist just not in the light beams level but also at the single-photon level (very surprising).
Detecting photons with orbital angular momentum in extended astronomical objects: application to solar observations https://www.aanda.org/articles/aa/pdf/2011/02/aa14844-10.pdf
Optical orbital angular momentum (2017) http://rsta.royalsocietypublishing.org/content/375/2087/2015...
Entanglement of the orbital angular momentum states of photons https://www.nature.com/articles/35085529
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We've had radio for just a little over 200 years and we've already realized its limitations. The fact that we can even speculate about quantum communication leads me to believe that radio is definitely NOT the end-all-be-all. If you scale human civilization into a 1 year time frame we invent radio at 3PM on December 31st. It's successor likely emerges January 2nd at the latest. Radio communication is likely a blip.
Radio is efficient over short terrestrial distance but horrible for long (galaxy scale) distance communication. If interstellar travel is feasible at all it will have to be at FTL speeds and an FTL communication system would be necessary.
If FTL is truly impossible then it doesn't seem like there is much point in listening since everything is so incredibly far it's irrelevant even on a species-level or planetary-level time scale. I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources.
Isn't this like saying every historian must believe in time travel? Just because you can't visit someone doesn't mean you can't learn from them.
Who is it that's speculating about quantum communication? Certainly not physicists. It's mostly just IFLScience!-class journalists seeing a term like "quantum teleportation" and assuming that it means start trek is real and write their articles based on that.
> I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources.
If everyone at SETI believes that mysterious FTL communication exists, then why do they spend all their time looking for EM signals?
Why is that? Special relativity already demonstrates that space contraction at near light speed would allow interstellar travel at human scale duration, with the side effect of time dilation for moving observers.
See: https://en.m.wikipedia.org/wiki/Twin_paradox
Probably true on a species level, but you are vastly underestimating how long a planetary-level timescale is. A von Neumann probe could cover the entire Milky Way in relatively short geological time.
For inter-stellar communications of sufficient distance, some sort of massive object (i.e., a space ship) seems like the preferred method because it can go at almost the speed of light, but it doesn't spread out over distance, can make minor corrections to its course, visit multiple destinations, and do something such as return a message, learn about its surroundings, and so forth.
I'd guess that a civilization might go through a period where it is emitting lots of easy-to-detect radio signals, lasting maybe a century, so we have to catch them at just the right moment.
It relies on the same mentality as the Fermi Paradox: it expects that an advanced civilization will master so much energy that its waste should be visible from afar. Only recently have we started considering that efficiency, rather than wastefulness, may be the hallmarks of civilization.
But yes, everybody at SETI knows that what they are doing are stabs in the dark. It is like trying to find inhabited lands by looking for tam-tam songs along the coast or to check if there are lighthouses installed where people may have switched to GPS.
Still, if there are thousands of civilizations out there, you can bet on off-chances of detecting one. The odds are low but the rewards would be huge. Fewer discoveries would be as consequential as this one.
[1] https://en.wikipedia.org/wiki/Duga_radar
So then similarly, it seems possible that advanced intelligence could be screaming at us but we're too "simple" to be able to understand them or even be aware of their presence.
Quantum entanglement does not, as far as we know, enable superluminal transmission of information. "Teleportation" is implementation-dependent and at this point entirely science fiction. If you're going to rip something apart or non-destructively scan it, and rebuild it at the other end, which is the only "realistic" theory of how it might work, you either need to transmit the bits or the bits (heh) and then you're back to the same problem of information transmission.
Of course we don't know everything, but the discussion really ends there: we don't know what we don't know.
We don’t know that there is anything better, but given how much we don’t know it’s not unreasonable to consider that we might not have the technology to receive communications from more advanced civilizations.
I agree with you that RF is a good communication medium given what we know, I just don’t put much weight on our existing knowledge being all there is.
This implies a common assumption among people: That any civilization out there is automatically going to be more advanced than we are.
If you believe that the universe started with the Big Bang, then (IMO), it's reasonable to believe that we all had pretty much the same amount of time to evolve and develop civilizations. Asteroid events notwithstanding.
To me, believing that all beings average about the same place in the development cycle, it makes sense to look for the signals we know, rather than the signals we don't know.
But I'm no scientician.
Also, I can't use language bi directionally with a plant no matter how hard I try. Maybe we're the plants. Maybe they don't have language.
So that window holding our current level of communication abilities is 0.15% to 0.05% of our species' age, and our species is in a similarly tiny window.
To the side now with assumption they might communicate chemically only between themselves... WHAT IF their clock rate is way slower than ours? Like snails, or plants. Their bitrate of communication would be undetectable to us, if they're way slower. I suspect it would be detectable if their rate is higher though.
That would mean most civilizations in our galaxy could be very much older than ours.
Radio only came about 100 years ago for us. Some new form of communication could be 100 or 1000 years out, which is no time at all on these scales.
Smoke signals will have been around for a lot longer than radio. Smoke signals will have been around for 99.9% of the timeline and then 0.1% radio before quantum. To an outside observer it would look like radio was just skipped.
If you scale human civilization into a 1 year time frame we invent radio at 3PM on December 31st.
Such a relatively instant means of communication would become the defacto standard. Antiquated EM methods and equipment would be forgotten. Noone would be listening for it, just as very few today would recognize semaphore flags, smoke signals, or telegraph codes.
Today we'd not be eligible to join that club. And if we choose to remain certain that it doesn't exist, our determined ignorance would keep us locked out. If we conclude that we aren't special, that there -must- be life elsewhere, then the only logical thing to do is to keep our minds open and keep looking for clues.
We can't ever decide that we know enough. A century ago, the Milky Way was the whole universe. A few more observations changed that forever.
The book covers many many possibilities for how a civilization might try to communicate or get the word out from Von Neumann probes to leaving something in our DNA, which could easily last multiple millennia to monuments...etc etc. It also covers the search for life elsewhere like looking for reverse chirality DNA on Mars (basically there is no reason all DNA found on earth should curl one way and finding DNA that goes the other way strongly suggests it didn't come from us).
- use the lowest common denominator long range communication medium (like EM waves), not the most advanced technology available to them, and
- would broadcast it widely in spatial, temporal and spectral dimensions and not worry about efficiency
Quantum entanglement is rather about correlation and statistics, which is, hopefully, will be quite useful for some applications, but not for communication channel. Otherwise, it will ruin the current foundation of quantum mechanics.
I strongly recommend reading the book of Nicolas Gisin 'Quantum Chance' [1], which is quite good for the general audience to understand, what quantum entanglement actually means in the real life, i.e. in the physical experiment.
[1] https://www.springer.com/gp/about-springer/media/press-relea...
These SETI signals, if they were of intelligent origin, would be showing just how dumb these aliens are. To send a presumably fairly local signal in such a way that it wastes such vast amounts of energy that it can be picked up 3bil ly away would seem like a serious transmitter design flaw.
Say you want to communicate between 2 star systems all you need to do is to position say a polarizer between at the edge of each solar system such as that polarizer can obstruct a suffiently large portion of the star from the point of view of the system you want to communicate at say the edge of a solar system it won’t even have to be that big.
You use the polarizer to modulate the passing light and encode your message onto it.
The concept is used in the "The Three Body" trilogy.
Terence McKenna Psilocybin - Magic Mushroom Grower's Guide
This probably really should be five questions.
1. For an advanced civilization trying to communicate to other, unknown, civilizations like ours. In other words, intentionally trying to have our SETI folks notice them.
2. Similar, but trying to communicate with a civilization that their SETI folks have detected. E.g., they have picked up on our existence from our EM emissions and want to to strike up a conversation.
3. For an advanced civilization that spans multiple star systems, not intentionally trying to communicate with anyone else.
4. Similar, but only spanning multiple planets within one system.
5. Finally, for an advanced civilization that is only one planet, not trying to communicate with anyone else.
For #1-4, EM is the most likely answer for reasons numerous others have mentioned. For #3 and #4, the big issue would be power. If they are only intending internal communication they might not be putting enough power for us to pick it up unless they are close to us.
For #5, even if they have not discovered something beyond the physics we know, they might not radiate their EM in a way we can detect. For example, if they have a planet wide urban civilization they might have every building connected to a high speed wired communication system. The only wireless they use might be something like Bluetooth or low power WiFi that only needs to communicate within a single room of a building between their portable devices and that room's node on the wired system.
Another interesting question is if they are EM radiation.
It should be the most efficient way to travel. Going from Turing machine to Turing machine, a virus with a really advanced universal exploit, impregnating civilizations like ours around the time they develop both radio tech and computers.
Civilizations with the capability to travel in that fasion would be dominant.
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At a scienctific level no, but in science fiction you have devices like the 'subspace ansible' and similar things that allow FTL communications by using some sort of currently-undiscovered 'subspace'.
I actually remember in the mid 90's seeing, in the Weekly World News (a sensational tabloid for those unfamiliar) or its primary competitor at the time, mention of a intelligence agency that had laptop like devices that allowed for real-time encrypted communication anywhere on the world which was likely a spin on this idea (IIRC it was suggesting some sort of quantum entanglement where doing something to one would instantly cause the same to happen on the 'paired' device so you'd just type on one and it would instantly appear on the display of the other).
There's no valid reason to think something like this isn't possible, or even plausible. We didn't discover infrared until 1800, x-rays and radio until 1895.
There could very well NOT be anything that would allow for FTL/real-time communication over any distance but then again there could be. There could very well be some sort of radiation or similar particle that we've yet to discover too which might be the preferred means of communication for an advanced enough civilization.
Look how far computers have come since I was born in 1985. Look at other technologies like genome sequencing, the human genome project took 13 years and cost many millions but now you can do whole genome sequencing commercially with an 18 hour turnaround and hire your own whole genome sequencing out for 500$ with a 10-12 week turnaround. I know these examples don't compare but what I'm getting at is we are barely a technological species and who knows what possibilities exist for us.
I mean, before we knew that radio waves exists we could not forsee the use of radio for communicating
so, I'd say that better ways of communicating relay on something that physics hasn't found yet (like, you know "that weird supersimmetry decay thing that only su-top quarks do when reacting with Stuff")
Likely we are searching for radio waves and light since that's the only thing we know how to communicate with.
Maybe there's another form of communication we haven't discovered yet that's so much faster and more efficient (like Star Trek's "subspace") that everybody else in the galaxy uses that instead. For them to send radio waves to Earth might be like us pointing Morse lamps at Alpha Centauri.
Trying to detect alien life by scanning the EM spectrum sure is inefficient. Maybe it's the best we can do, but if there were something better, I could totally see why we'd abandon plain old radio waves.
Personally until we've figured out things like consiousness and dark matter/inflation etc I think the null hypothesis should be that there is unexplained stuff happening and thus it's likely advanced civilizations use something other than electromagnetic waves, just like we don't use smoke signals or fire beacons much for communication anymore.
SETI would become search for extraterrestrial intelligence that that believes it's worth a shot to emit RF to contact less advanced civilisations that at the moment of recieving the signal will be in that small time window when they used RF for communication because they had nothing better.
The two dimensional lifeforms were unable to perceive three dimensions. Yet at the same time, the crew of the TNG struggled to understand them.
First, they have mass, hence travel slower than the speed of light, which means they are less effective.
Second, it is very hard to detect neutrinos, which means they are very bad communication medium.
We use lasers for quantum teleportation. There's no reason to believe it can be realised more efficiently without.
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Relevant to this topic:
- Fermi Paradox series (15 videos) [2]
- Advanced Civilizations (19 videos) [3]
- Alien Civilizations (10 videos) [4]
Of particular relevance is the Kardashev scale [5]. The basic idea is this: unless something catastrophic happens, humanity is destined to become a Kardashev-2 ("K2") civilization without a blink of a cosmic eye (measured in thousands of years). Since the timeline from sentience to K2 is so short (cosmologically speaking) it seems pretty unlikely there are other spacefaring civilizations in our galaxy.
It's worth noting that the scale of such a civilization is so immense and what it is capable of with access to that much energy and resources tends to debunk a lot of ideas that come out of a search for explanations to the Fermi paradox.
For example, there is the idea that civilizations might "hide" and would not be detectable. Such an effort would be futile vs a K2 civilization however.
I mention this because there is the idea that aliens might not use radio technology. Doing so wouldn't keep you hidden from a K2 civilization so there's no point in trying. And I find this a compelling line of reasoning.
[1]: https://www.youtube.com/channel/UCZFipeZtQM5CKUjx6grh54g
[2]: https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh...
[3]: https://www.youtube.com/playlist?list=PLIIOUpOge0Ls3WMYP_2Fp...
[4]: https://www.youtube.com/playlist?list=PLIIOUpOge0Lu97HzMt_BJ...
[5]: https://www.youtube.com/watch?v=dArpj_VxxuQ
Now we take electromagnetism for granted and can observe it everywhere, as it has always been. Yet the problem with this is that now, in order to have any meaningful discussion of the things of which you're speaking, you have to make the very questionable assumption that there will no longer be similarly revolutionary forces we will discover in the future. And so there comes a question of weighting that. What are the odds of that being true?
Our species' entire basis of knowledge is formed, almost exclusively, around observations based on one planet, in one solar system, in one galaxy. Everything else is just reasoning based on incredibly coarse observations of everything else. I think the idea that that we're even remotely close to unlocking the true nature of our universe is not really logical by any measurement other than 'well we're trying really hard and haven't been able to make that next step yet' which has, of course, been true throughout our species entire existence -- until that next step is invariably made. The increasing difficulty does not indicate anything like evidence of approaching an end to revolutionary discovery itself. Yet if we're not at the end then any meaningful big picture or very long term predictions are going to serve as little more than the butt of jokes for those with the opportunity to read such predictions from the future.
New technologies exacerbate this problem rather than solve it. As do new physics. In fact Isaac mentioned multiple times that the inability the apparent absence of evidence of advanced civilizations is the best evidence for there not being FTL travel or communication (as just one example).
So while i can agree we don't know everything I'm not sure why it matters.
Anyhow, the point here is that once a species reaches this level of technology, if it's possible, they will start to move beyond anything like the borders of time as we understand them.
In my opinion, the most simple and probable explanation is technology (we don't know what's out there), but that's closely followed by the terrifying great filter being complete and unadulterated pleasure. As lives become easier and more pleasurable, the inherent drive towards procreation becomes less and less of a factor. If that reaches below a certain point, that's lights out for a species. Create a guaranteed means of subsistence on a planet, perhaps entirely automated, and now create a technology that becomes more inherently enjoyable and rewarding than procreation itself. Congrats you evil villain, you've destroyed your species in a far more effective way than any weapon ever could. Society goes out not with a bang, but also not with a whimper; they go out with a moan of pleasure.
[1] - http://convertalot.com/relativistic_star_ship_calculator.htm...
It’s important to remember that we are not arguing if some if not many or even most civilizations destroy themselves. For this to explain the Fermi Paradox you’re arguing that basically all do and there are lots of problems with that argument.
Dyson spheres are not subtle. We can say a high degree of certa8nty that no Dyson spheres have emerged within a billion or so light years of us where light has had time to reach us or we would’ve detected them.
Say 10,000 civilizations rose up within that sphere. Even if 9,999 of them destroyed themselves we would detect that 1 tha didn’t.
The telescope is available on a rental basis. People just schedule it to point it wherever.
That depends on what you mean by "associated". It's not associated directly with SETI the institute, but it was the site of the first systematic/scientific search (and false positive) for extra-terrestrial intelligence lead by Frank Drake. It is also the place where The Order of the Dolphin (Drake, Carl Sagan, Otto Struve, et al.) met and developed the Drake Equation.
and paper : http://blpd0.ssl.berkeley.edu/frb-machine/CNNFRB_eprint.pdf
The short bursts, which range from 30 microseconds to 9 milliseconds in duration, indicate that the source could be as small as 10 kilometers across – the typical size of a neutron star.
Other possible sources are a magnetar interacting with the nebula of material shed when the original star exploded to produce the magnetar; or interactions with the highly magnetized wind from a rotating neutron star, or pulsar.
[0]Do any terrestrial sources create polarized radio waves? Would polarization help beamforming or other range-extending techniques?
[0]http://news.berkeley.edu/2018/01/10/seti-project-homes-in-on...
> All radio (and microwave) antennas used for transmitting or receiving are intrinsically polarized. They transmit in (or receive signals from) a particular polarization, being totally insensitive to the opposite polarization; in certain cases that polarization is a function of direction. Most antennas are nominally linearly polarized, but elliptical and circular polarization is a possibility. As is the convention in optics, the "polarization" of a radio wave is understood to refer to the polarization of its electric field, with the magnetic field being at a 90 degree rotation with respect to it for a linearly polarized wave.
https://en.wikipedia.org/wiki/Polarization_(waves)#Radio_tra...
So it's less that it helps, and more that it's inevitable.
https://www.stufftoblowyourmind.com/blogs/symphonies-of-the-...
>For instance, the probes picked up the interaction of solar wind on the planets magnetospheres, which releases ionic particles with an audible vibration frequency. Essentially, we can then translate these waves into sound waves and put them on an album.
https://archive.org/details/SymphoniesOfThePlanets2
https://archive.org/details/SymphoniesOfThePlanets3
SoundCloud: https://soundcloud.com/xca8biolusw4/sets/seti-space-noise-ma...
Conversion script used: https://gist.github.com/ptytb/6eade153de6f54dbc0fc1fc0d46993...
Narrator: It wasn't.
>> This could be huge!
Don't get me wrong, I appreciate the humor and understand how the media tends to over hype any news that could potentially excite people interested in the discovery of little green men, but I never felt that this particular article was doing that.
that's only 0.00051 of a light year, or a few light hours away.. either me or them has a big math problem.
PR: https://breakthroughinitiatives.org/news/22