# A plausible explanation for the "ansible?" - FTL communications

I need FTL interstellar communication in my story. Ursula K. Le Guin first used the idea of the "ansible" as a fictional device or technology capable of near-instantaneous or superluminal communication. It can send and receive messages to and from a corresponding device over any distance or obstacle whatsoever with no delay, even between star systems.

I would like to have some sort of "plausible" explanation for this that doesn't need to be hard science. Orson Scott Card had his own version that was build on a subatomic particle and rays. I want it to seem as little like magic as possible.

In my universe, ships travel via hyperspace - so I wondered if I could use that. Here is my working solution:

1. Planet sends out message in some sort of "packet" that moves at the speed of light, or close to. So either via an electromagnetic wave, or even a temporary physical packet holding the message (not sure if that is needed).
2. This packet enters hyperspace, heads to the proper galaxy and emerges, just like ship.
3. The packet "opens" and broadcasts the message back as a wavelength as normal, where it can be received.

What I like about this is that the message travels like a ship, and has the same restrictions so it's not quite instant. But it is fast enough to have some sort of communication across distances.

Question: Is this "possible?" What would the package look like?

If anyone has any builds, I'm open to ideas too.

Edit: Thinking of calling it simply the "hypercom."

Edit: I don't want to use Quantum Entanglement. From my previous question on transmitting data via waves:

"While this is a common idea in scifi, as I understand it the real world version cannot, even in theory, transmit information by any means regardless of hypothetical technological advancement. It can only synchronize randomness, allowing secure uninterceptible establishment of an encryption key to be used on information sent via other channels." - Douglas.

• I don't see any problem at all! You have decided to use hyperspace. You get to make the rules. So make the rules so signals can travel very fast through hyperspace. Done! Jul 28 '20 at 18:43
• "I want it to seem as little like magic as possible." Unfortunately, that's the fundamental problem. As Clarke put it, "A sufficiently advanced technology is indistinguishable from magic." You're looking to do what Le Guin, Card, and many others have already done: invent a string of technobabble that isn't the technobabble they used but still sounds credible. Both fortunately and unfortunately, other than one way of looking at tachyons (simplistically: what happens to one happens to all simultaneously), there is no current tech to build on. (*continued*) Jul 28 '20 at 21:05
• Regrettably, what that leaves us with is an opinion-based question. Other than agreeing with you (you've already solved your own problem by using "hyperspace," you just need to define what that is as a worldbuilding system), no answer can be given that's any better or worse than any other, which is prohibited by the help center. Is there a way to edit your question into a one-specific-question/one-best-answer format? Jul 28 '20 at 21:07
• If you say that hyperspace has a preferred reference frame, that'll answer the question of how you can have FTL without problems with causality (see this section of a good FAQ on FTL travel) Jul 29 '20 at 0:23
• Does the story require a realistic explanation? if not, don't explain it at all. No one cares and it will be gibberish anyway. Jul 29 '20 at 19:36

So, you have hyperspace. First you need to decide how that works in your universe. The most common fictional version of hyperspace is a space much like our space, except that distances are shorter.

So, you pop over to hyperspace and move a short distance. When you return to our space, you find yourself a long distance away from where you started. The ratio between the two depends on how fast you, the author, want space travel to be.

It must be possible for humans to survive for a short while in hyperspace. This means that physics must work pretty much the same there. In particular, electromagnetism exists and radio signals work.

So you basically stick an normal radio antenna into hyperspace and send normal radio signals. Easy work. Note that this allows for both directional antennas for messages and broadcast antennas for hyperadio stations.

You also have to decide how non-hyperspace space flight works. The technology we have today is painfully slow. Even going next door to Mars is a major undertaking. You probably want to speed that up.

Let us say that a space ship can move in normal space at 0.001 c. This means that radio signals are one thousand times faster than space ships. This is a gross simplification, since space ships don't move at a maximum speed, but rather have a maximum acceleration. But this is all just for getting numbers to play with.

Since physics are similar in hyperspace, radio signals are one thousand times faster than space ships there too. If space ship travel takes a day, a radio signal will take about a minute. Not instantaneous, but pretty fast.

It is possible to speed this up, if you want. There can be several different hyperspaces. Space ships only use the slowest hyperspace, for one reason or another. I suggest that the fast hyperspace is hard to navigate, it is very difficult to arrive anywhere close to where you want to go. Radio signals have no such trouble. They arrive everywhere.

It is very difficult to make any FTL theory actually work as a consistent physical theory. The most major problem is avoiding time travel. Relativity as we know it state that FTL travel implies time travel. This may be wrong, but it is pretty hard to make an alternative that both matches the world as we see it around us, allows FTL and disallows time travel.

A less important problem is conservation of energy and momentum. This is more likely to be false without impacting the story you want to tell.

My suggestion is simply ignoring these problems. Time travel is impossible, but the characters don't care about why. In fact, neither the characters nor the narrative should mention time travel at all, to avoid the reader starting to think about it.

And it might be possible to get energy from hyperspace. This might be your main energy source, OR it might be too expensive to actually use much. Solar panels are pretty cheap.

Or it might be impossible, for reasons no characters care about. Who spends time thinking about the impossible?

• Great build, this is two now with antennae in hyperspace. I like it. Appreciate you taking the time to put this down! Jul 30 '20 at 12:58
• @Stig_Hemmer thanks again for this. I'm choosing this as the answer since it best fits my needs for the story. Have a great one! Jul 30 '20 at 16:53

You have hyperspace. That will make it work.

The prefix "hyper" to me refers to spatial dimension beyond our common 3.
https://en.wikipedia.org/wiki/Hypercube

If I have access to an additional spatial dimension I can use that to take a shortcut not possible in my ordinary dimensions. For example in 1 dimension a point must travel along a line to get from one end to the other. If I can bend the line in 2 dimensions I form a circle or spiral and I can put the end of the line right behind my point - a shortcut. If I am a flatlander moving along a 2d piece of paper, I can fold the paper over such that my destination is right above me in 3 dimensions. A shortcut thru that 3d dimension puts me at the destination without traversing all the 2d paper in between.

So too with the 4th dimension. I cut thru and arrive at my 3d space destination without having to traverse all the 3d space in between.

The transmission can be whatever medium can traverse that 4th dimension and come out in 3d space where you want. It could be radio waves which would be nice if you want your transmission to come out into empty space as the Millennium Falcon hopes to do. If you are utilizing wormhole Stargate type things then you open the Stargate and transmit thru with your broadcaster, just as you would broadcast to your people at some distance in your own 3d space.

• This is interesting, and mirrors things I read in Hyperspace by Michio Kaku (before it got over my head and I gave up.) So let's say it's a "dimensional com." I fire off a normal message via some wave into that dimension (special equipment yadda yadda) and it drops out somewhere else where they have the same coms that are listening for such messages. Yeah? It would be nice to have some delay in it that isn't too long. Jul 28 '20 at 18:36
• @MajorTom - well, if you are using electromagnetic radiation you have the delay of the speed of light. 3 minutes from here to Mars. If you want it longer, you can have it take some arbitrary amount of time to traverse the 4th dimension. amounts. Jul 28 '20 at 18:44
• Ok - let's say I'm in a planet in a different galaxy - Ursa Minor - on some planet. I want to send a message to Mars in fact. If I am sending direct to the 4th D, and Mars is listening directly for stuff from the 4th D - is there any delay at all in such a proposed system? (Aside from an arbitrary delay to send to 4D). Jul 28 '20 at 18:52
• Ideally your stuff pops out in 3d dimension headed for Mars. They would need to know your broadcast frequency but that is it. Just like I can listen to college radio from up the street or the Top40 station broadcasting from 20 miles away. The delay would be how much normal space the signal had to traverse before going thru hyperspace. Jul 28 '20 at 19:06
• I think since you said ships take time in hyperspace, EM sent through hyperspace would be bound by the same-ish rules, so you can set the speed to whatever you want from ship speed up to near-instant Jul 29 '20 at 5:43

Yes.

You have decided your universe can use hyperspace. Hyperspace is fictional in the first place. That means you have freedom to pick the rules. Just pick the rules so that signals can travel fast enough to be essentially instantaneous.

But is it "Possible"?

It will seem more "possible" if you decide consistent rules for how hyperspace works and stick to them. Here is one example of a rule: The speed a package can move through hyperspace is proportional to the inverse of the mass-energy. Since a signal has much less mass-energy than a spaceship it can travel much faser.

What would it look like?

Spaceships have big machines called Hyperspace Rams that open and close the door to hyperspace. Since your signal is just some electromagnetic waves it cannot carry the ram with it. So I imagine two permanently open ram stations that permanently keep a small door open between System A and System B and you just shoot your signals through.

• I love the idea of ram station. You said "The speed a package can move through hyperspace is proportional to the inverse of the mass-energy. Since a signal has much less mass-energy than a spaceship it can travel much faster." -- Is it still up to me to decide how fast? If a message moves close to C within hyperspace, does the message seem "instant?" Jul 28 '20 at 18:54
• @MajorTom: I made up the term Hyperspace Rams just now for the piece of technology that opens up the door. You may use any different name you wish. Jul 28 '20 at 21:04
• @MajorTom Isn't the whole point of hyperspace being able to move much faster than C? Jul 28 '20 at 21:06
• @Daron not necessarily it maybe be that you are still limited by the speed of light in hyperspace but the distance between 2 points is much shorter if you take a route through hyperspace than if you travel in normal space
– jk.
Jul 29 '20 at 11:51
• A thought: who is this explanation for? If it is for you to keep the facts of your story straight, that's fine. But if it's so one character can explain to another, keep in mind that neither will understand it well enough to explain beyond similes & oversimplifications -- unless you have one physicist or engineer talking to another, & they avoid jargon. Just because someone uses a tool doesn't mean one completely understands how it works. Do you understand how your car works down to every nut & bolt? Most people have only a superficial understanding how their car works. Jul 29 '20 at 16:10

## Starting with the Oldest Debunked to Still Undetermined

Tachyons:

Although the field itself might spread faster than light, disturbances in the field move at light speed.

Neutrinos:

So far all hopes for faster-than-light neutrinos have been explained by measurement or calculation errors.

Wormholes or Strange Space-times:

We had all hoped you could compress space infinitely, so that far distant reaches could be just a step away, given enough power.

However, recent observations have shown that the entropy (energy) of black holes increases not with the volume enclosed, but rather with the surface area of the event horizon. Suggesting there is a limit to how much space can be squeezed, nothing goes inside a black hole, but instead travels slower-than-light along the event horizon.

Alcubierre / White "Boost" Drives:

These relied on a hope that the speed of gravity through space was far faster than the speed of light. However, recent observations of gravitational waves have shown that the speed of gravity is equal to the speed of light.

Fifth force:

Very recently, while looking for dark matter, some unusual new physics might have been observed - a new fundamental force to add to electromagnetic, weak, strong, and gravity. It's hard to say yet what it does.

Non-constant fine structure:

There's some observations suggesting the fine structure constant $$\alpha = {{e^2} \over {hc}}$$ might vary. This might mean new physics exists that tweaks one or more of these properties (hopefully c).

Inflation:

The universe expanded at a speed of in the neighborhood of $$Speed Of Light^7$$ for all of $$10^{-35}$$ to $$10^{-30}$$ seconds. Or at least, that's what we think. There have been subluminal explanations provided, but there's the possibility that new physics lies here. Also, it's assumed that if any new physics do exist in this region that the energies required are an insurmountable barrier.

If new physics allows for FTL either by changing the fine-structure constant, or somehow re-creating the conditions of inflation at far-lower energy levels, you could signal with this field (just like wireless telegraph or radio).

• James, thanks for taking the time to do this. It's really helpful to consider all these. Much appreciated. Jul 29 '20 at 1:23
• Hmm, there seem to be a number of misinterpretations and/or misunderstandings here. Could just be me I guess... Jul 29 '20 at 12:25
• I could be wrong. If there's something specific, would be happy to look at it more. Jul 29 '20 at 13:08
• Can you back up your statement that speedOfGravity=c invalidates Alcubierre drives? I can't see anything in wikipedia connecting those two, and the accepted answer to this question disagrees. Jul 29 '20 at 13:46
• Sure, but it'll take a bit to dig up. There's a line in either Mr. White or Mr. Alcubierre's paper that I interpreted was an assumption in their work. Jul 29 '20 at 15:14

Question: Is this "possible?" What would the package look like?

It would look just like whatever medium you sent it. In the words of Our Immortal Lady GLaDOS:

Speedy thing goes in, speedy thing comes out.

If you send that information in the form of a USB drive on one side, that then travels in a spaceship on hyperspace, you will have a USB drive on the other side. This is similar to what some people have done on Earth before with pigeons, except that here on Earth no one violated causality. You, on the other hand, are bound to receive a fine from the Auditors of Reality, because FTL in any form implies violations of causality.

• This is essentially the approach in Honorverse; ships can travel FTL, but (initially) communications can't, so you get "space mailmen" running around doing exactly this (well, you usually transmit electronically to and from orbit; exclusive hand-carrying of physical media is only used for really secure stuff; the sort of messages that come in a briefcase handcuffed to a courier). (They do later develop FTL comms, but they are limited to intrasystem range.) Jul 28 '20 at 18:09
• Are the ships moving FTL via hyperspace? I've always been fuzzy on that. I thought essentially what is happening is space is really folding or compressing together, the ship itself isn't really moving. In any event, waiting for a ship to take it seems pointless when I could just shoot the darn USB drive itself into hyperspace. If it's a "probe" it can do its own communications. Jul 28 '20 at 18:26
• @MajorTom it depends. Hyperspace is an umbrella term for all sorts of FTL travel in sci-fi. In physics there is a proposed mechanism called Alcubierre Drive, which does allow for actual FTL by compressing space - the ship never goes faster than the local speed of light. But this is a detail that does not matter - if you reach some place faster than light would, the means don't matter - wormhole, hyperspace, space stone etc. - you've already violated causality. Jul 28 '20 at 18:29
• Ah! That makes sense. It seems like universes like Star Wars simply ignore that fact then. Jul 28 '20 at 18:33
• @MajorTom - if you want interstellar space opera, you have to ignore it. Causality does a lot to kill drama if your ships have to travel for centuries. Star Trek would be very dull. Jul 28 '20 at 18:36

If Wormholes can be created you could use them for both travel and communication so long as the voyage or message did not violate causality. Which leads us to;

The 1st limitation on wormholes. Causality wins - every time. There are a certain specific set of conditions where in theory causality can be broken by wormhole messaging or travel. The result of which is the immediate collapse of the wormhole. This in itself is not 'dangerous' because causality prevents the breach from occurring so no message or ship can actually enter the wormhole - the mere attempt to do so causes it to collapse. It is however ruinously wasteful and expensive.

2nd limitation; I suggest that your wormholes are realtivly easy to create but one end then has to 'delivered' by a sub-light probe to the target destination. If a system is 100 LY away then unless you have a 'chain' of wormholes already established leading closer to that point you have to wait > 100 years for the wormhole to be useful. Note trying to thread a wormhole though another wormhole is 'bad' for all concerned - especially any crew on the ship attempting it

3rd limitation; while tiny (sub microscopic) wormholes can he generated fairly easily on or close to Earth larger/stable ones need to be placed in suitable orbits some distance from the planet. This is because wormholes nullify distance. Put one end of a large diameter wormhole on Earth and the other in orbit just above a Jupiter sized planet and the gravitation field of that planet also gets to travel through the wormhole. (Everything does) This would be bad. So you have to place large ones at least where they won't interfere with planetary orbits at either end.

4th limitation; wormholes are pets - they need to be fed and taken care of. They are not stable once 'spun up' but decay into nothingness unless (expensive) exotic matter or its counterpart is replaced as required based on a complex set of equations and observations made by those charged with maintaining the network. Ships passing through can do this.

5th Limitation; Time - since you wormholes are some distance away from the inner planets of any 2 linked systems (and probably in highly inclined (polar orbits) A laser or radio signal from Earth to a distant world will take some hours to reach the initial entry point then (no time) to transit the wormhole followed by more delay as the signal is relayed to its final destination or the next wormhole in a chain,.

So nothing is for free. If you have a large extensive network messages will still take weeks to reach their destination. You might be able to spin up small (tiny) wormholes on small stations or satellites closer to Earth but the longer the network they have to pass through the longer the message takes. So some time saving for 'shorter' hops but not a huge amount. (Still beats centuries though.)

• Appreciate the thoughts. Thanks. Jul 30 '20 at 12:52

A lot of what you want is done in the Culture series of books by Iain M Banks, I recommend copying as it's more consistent than the mere concept of Hyperspace, and attempts to fix a lot of the issues you might encounter with explainability.

Take 2 antenna, and twist/lever them into and across the Hyperspatial dimension. Now they broadcast across a 4th dimension. You can use the same technology that ships use to create these antenna, but keep one end anchored so it doesn't completely enter hyperspace.

Now you have a portable transmitter in the 4th plane capable of FTL comms. Hypercoms!

Given that ships with mass can travel at FTL speeds in Hyperspace, just imagine how much faster massless photons would travel in Hyperspace! Case in point, Star Trek has subspace radios that rely on the same premise, although I don't think subspace coils are partially in subspace in that franchise.

Since you're in hyperspace, you can say the speed of light in Hyperspace is much higher, or that exotic equivalents to photons exist only in that realm and are used instead.

### Aiming Transmissions

You can then aim your transmission much the same way you would aim a conventional transmission, with techniques such as directional antenna, beam forming, etc

Keep in mind though that you have a whole extra dimension to aim in, just because you're pointed at the target in 3D, doesn't mean you can ignore the extra axis added by 4D/Hyperspace. Pointing an antenna downwards won't help if your target is above you, the same is true here, which leads to..

### Power Consumption Mechanics

It may help to orient your antennas along a common 4D plane or axis. Because 3D space we have to work within the inverse square law, adding an extra dimension multiplies that to a much larger extent. 4D space is an order of magnitude more vast than 3D space.

So sending an omnidirectional 4D broadcast will dissipate faster, reducing range. How this interacts with the greater transmission speed as well as targeting is up to you, and leaves you lots of plot mechanics.

For example, perhaps both ends of the Hypercom system have to ping eachother and locate 4D coordinates, then once they're locked on to eachother they can send tighter focused beams through 4D space? Or maybe one end needs to have known coordinates to send transmissions to? Perhaps the geometry of the antenna will provide access to limited subsets of 4D space?

Keep in mind there is no need for transmission or reception in 3 dimensional space itself

A sidenote, if you mess with the speed of light you mess with basic chemistry, I'd advise stealing a common trope of surrounding your ships in a bubble of realspace, e.g. 40ks gellar fields, or the insides of ST's warp bubbles, or the fields Borg cubes use to prevent temporal instability when using transwarp. Thankfully none of these are required for data transmission

This also allows for some unrelated items:

• 4D Cables Ducts and Pipes, ethernet cables that curve into the 4th dimension then back, allowing unconnected things to be.. connected. Sending material a short distance through a wall for example, or between 2 ships without them touching
• Floating supports remember how in Jupiter Ascending the ships had little floaty bits that somehow still moved with the ship? Turns out they were attached all along, their support just curved upwards into the 4th dimension then back
• Displacers! Unlike ST style transporters, we're going to do this Culture series style! We'll wrap the person in a bubble then use EM fields to move the bubble into the 4th dimension, across, then back out into a destination. Congratulations you have teleporters that don't cause philosphical issues!
• Hypercomm Jammers these work just like conventional jammers, but their antenna are in 4D space rather than 3D space. Expect them to take more power though as they have a greater area to cover
• HyperShields why protect yourself in 3D when someone can bend around in the hyperspatial plane and pop out inside with bombs? Presenting 4D shielding that wraps around not just the sides, the top the bottom, but the 4D bit too
• FTL ships lever themselves into the Hyperstial plane and accelerate towards a target, melding your Hyperspace FTL concept with Hypercomms
• FTL Jammers because Hyperspace is just the 4th dimension, you can apply the effects of gravity wells to hyperspace too
• This is an interesting build! And I like that there's the normal delay in getting the message to the antenna. You wouldn't want the thing too close to a planet in case something weird happens with the thing, right? I like this. Jul 30 '20 at 12:55

Quantum Entanglement

The idea of finding some way to utilize quantum entanglement is an idea that I have seen passed around a lot. As far as I understand it the base premise is that entangled particles will always act opposite to eachother, simultaneously, over infinite distance. So the idea is that if you can manipulate an entangled particle on one side you can then read it from the other in some sort of instantaneous binary/morris code with cup phones. I think there have been a few explanations as to why this would not work in reality, but it is also one of those things that you could handwave into a believable explanation for the average reader.

On a logistical note though, if said premise were possible, you would need to have the two points of contact physically in contact to exchange entangled particles beforehand. This would mean that FTL communication would be impossible between ships and stations that have never come in physical contact before.

• Quantum entanglement can't be used to send information faster than the speed of light, so I think using it in a story would be akin to invoking . . . buzzwords? Technobabble? I'm trying to think of the proper term. Jul 28 '20 at 17:50
• Yep, that has come up in another question. I don't want to use it - this is partly why: "While this is a common idea in scifi, as I understand it the real world version cannot, even in theory, transmit information by any means regardless of hypothetical technological advancement. It can only synchronize randomness, allowing secure uninterceptible establishment of an encryption key to be used on information sent via other channels." Jul 28 '20 at 17:51
• @HDE226868 I think the word you're searching for is magic. Jul 28 '20 at 17:54