How do we create an interstellar communications system?

Question

In my science fiction project, humans have settled in a new Galaxy, known as the Novan Cloud. In order to communicate information to other alien races humans require, alongside superluminal travel, (a problem I’ve already solved) a means of superluminal communication. And I’m stumped as to how they’re going to manage it. Any ideas?

If it helps at all, the means of interstellar travel people are using involves artificial wormholes that vanish immediately after creation, so function more like a teleporter than a permanent gateway through space-time.

Answer 1

Send USB thumbsticks through wormholes

Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway. -- Andrew Tanenbaum, 1981

You're not going to get information to travel faster than the speed of light if you're making it travel as EM.

But you've got teleportation. So: put all the info you want to transfer onto a portable storage device shaped like a space pony, and teleport it to the intended recipient.

Start doing it on a schedule. Design your telecommunications infrastructure to be eventually consistent, such that it can seamlessly integrate a data dump into its information universe at any point. Set up some kind of digest-production tech so that it's easy to generate each scheduled data dump.

Human society made do with long-distance comm tech that routinely had a lag of weeks or months (and which, coincidentally, was also shaped like space ponies). Your galactic society can probably get by with hourly sync-ups.

See also:

• The Obligatory xkcd ^{(if "What If?" counts)}
• The story of the proverbial station wagon

Answer 2

Have ships transmit data when they travel

Ships will tend to have massive computers and powerful transmitters. As such, have it be standard practice for them to send over a copy of the internet whenever they move systems. The more traffic a system gets the more up to date their internet will be, and the less traffic the less up to date they'll be.

This helps make space travel cheaper and more profitable as you can charge for updates, and ensures that everyone can contribute to common communication methods.

Use courier ships for important messages

If you need to send messages quickly you send a courier ship. This ship hangs around a good site for a wormhole and can quickly pop in to any system that you want to send a message to. It would be very expensive, but sometimes essential. They'd be built with powerful wormhole generators and powerful engines and transmitters.

Answer 3

In Real Life, communication cannot exceed the speed of light

That's because, insofar as we know, the speed of light is as fast as we can go.

But in your world, you have ships that travel faster than the speed of light. That means no communication can move faster than those ships (unless you invent a world rule to allow it). So, since we know very little about your world, those ships are it.

But how to maximize this opportunity?

If today's over-regulated transportation beauracracy is realistic^{<citation required>}, then it's reasonable to assume that your ships can't just open a wormhole anywhere. That would be legally and beauracratically chaotic! So wormholes can only be opened at a particular location (let's say a point 1,000,000 km away from the planet and always directly opposite the sun). Knowing that said location will always be where the wormholes open, what ships will discover is that along with the ubiquitous customs agents and duty-free souvenier shops is a massive com center that's constantly uploading data to outgoing ships and downloading data from incoming ships.

By law, every ship capable of FTL travel must have secure communications transport capacity in the form of highly encrypted transmitters that interface with the customs stations at every planetary (and every other) location.

If you're looking for a direct communication solution similar to your FTL travel solution, then you need to give up how your FTL works

Because right now there's nowhere near enough information to arbitrarily invent an FTL communication process that's consistent with your existing world rules.

Answer 4

I want to stipulate at the start that I'm not an expert on this.

But, if the wormholes are cheap to make and truly instant---i.e they are created instantly and travel through them is instant---then they can be used to communicate directly.

The simplest model would be to use miniature wormholes flashing open and closed like an aldis signal lamp to communicate morse code or similar. I suppose you could also arrange small wormholes much like the lights in an 80s scrolling neon sign, either high in the sky over a planet, or miniaturized into a kind of office ansible.

But I think you[*] could also create some kind of signal box, where the pulses of light from a fibreoptic cable, say, trigger the flash creation of a wormhole, and, on the other side, a receptor converts that information back into pulses of light.

The real question then would be what would be best for the story. Perhaps wormholes are so expensive that this is like an early telegraph? Or perhaps because it takes them 2 days to spin up, for whatever reason, messages have to be composed 48 hours in advance and are then delivered instantaneously, allowing for all sorts of confusion if events outrun them.

[*]With a little bit of sci-fi hand-waving, to be sure.

Answer 5

A Parallel Universe with a Faster Speed of Light

If the universe of your story had a parallel universe where the speed of light was must faster than usual, and travel between these universes wasn't too difficult, then there could be some interesting potential for communication.

Imagine pairs of automated stations, one in the ordinary universe and one in the parallel uninverse that switched places, alternately receiving and transmitting messages.

I think it would make sense if there was a relative time dilation between these universes, with the other one running faster. So a person wouldn't usually want to spend time in this universe, or use this for travel (not without some pretty sophisticated cryostasis), but communication would be interesting.

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Rereading the OP, you would probably want a bucket brigade of probes that teleported back and forth between locations, handing off the signals from one to the next probe.

Answer 6

Communication Came First

The ability to create massive wormholes, large enough to fit capital ships (presumably) didn't come out of nowhere. It developed over time, the technology slowly getting better and better. The first breakthrough was the ability to open nanoscopic bridges, connecting two tiny points in space, for a fraction of a second. With proper timing, these proto-wormholes could be used to instantly send individual photons any distance, but the cost to create them was substantial, limiting their effective use. Eventually the cost and time required to create these holes was reduced enough that effective transmission of data over any distance instantaneously was possible, albeit with severely limited bandwidth.

Size and Duration are Inversely Proportional

Over time, the technology improved. They were able to hold microscopic holes open for several seconds, allowing for bursts of data and greatly improving throughput, or momentarily create a hole just large enough to send tiny physical objects through. Eventually it was discovered that the amount of time a hole could be maintained was inversely proportional to its size.

The Latest Tech

After enough time, the technology improved so much that massive wormholes could be held open long enough for large capitol ships to get through, allowing for unbounded exploration. By this point, the technology was also able to hold open microscopic wormholes for several hours, allowing for instantaneous transmission of enormous amounts of data with almost no interference (since the transmitter and receiver are effectively adjacent to one another through the portal).

But, it's not quite that simple...

Wormhole endpoints are fixed in space, relative to the universe itself, not the observer. For large wormholes in the depths of space, this is a non issue as one can simply create the portal in front of wherever their total motion is taking them (i.e. when traveling against the direction of the galaxy's spin the ship might be moving forward relative to the surrounding stars, but backward relative to the universe as a whole, so the portal might need to be placed behind the ship. From the ship's perspective it would appear to move up from behind, overtaking the ship and transporting it starting from the rear).

However, opening a fixed location microscopic portal from a moving location would result (relatively speaking) in the portal shooting out in the opposite direction of the locations motion, with potentially devastating consequences. To solve this, the portal would need to be opened for a split second, sending a small batch of data through. With advanced enough technology a new portal could be opened hundreds of times a second, minimizing loss of throughput.

Hold on, it get's worse...

But if both ends are moving, how does the transmitter know the exact location of the receiver? The other end of the portal would need to be opened with pinpoint accuracy, but the only way to get the data there fast enough would be via a portal, creating a kind of paradox. One solution would be to have each node able to calculate a function for its own future motion and broadcast it out to all available nodes based on their motion functions. If this function changes (because a ship turns for example) a new function is calculated and broadcast. If a node does not have a particular node's motion function it can query other known nodes to see if they have it. Hooking up a new node simply requires the motion function of a predictable node (which could even exist for the express purpose of calibration). Once connected to a single other node, it is easy for the new node to scan/probe the network for all others. With a node's motion function, last known location and time since last connection, it should be possible to calculate the exact location of the receiver at any point in time.

Answer 7

Gravity waves

Nevermind sending radio or physical storage through wormholes. Popping such holes, big enough to allow for ships to pass through, in and out of existence should cause huge gravitational waves on both ends. This would be very easily be detectable. On some accounts a 1m (~3 ft) wide wormhole should be as massive as Jupiter at the very least, so a ship-sized one would likely have considerable stellar mass.

And if you have the technology for that, you should also be able to create miniaturized versions of LIGO (a gravity wave measuring tool we have in real life).

Just open and close some smaller blackholes to send a signal encoded in gravity waves. With proper modulation and other signaling techniques, you should be able to tune into a channel and filter out the noise from the other wormholes used for ship transportation.

For the record, it has been discovered recently that gravity waves move as fast as light. Since they would be coming from the wormhole ends, it would be as fast a form of communication as radio or light.

Answer 8

A combination of some of the below (inspired by some answers above)

I'm not sure how exactly your FTL travel works, but if you can produce wormholes for amounts of time long enough to get a spaceship through, you should also be able to use them for data packets, in various ways.

What I don't know is how hard it is to make those wormholes, and whether you can only produce them in certain places, or if you could have a machine in your basement producing small holes of the size of your fingernails, at a rate of one per minute. So depending on how hard this is (or how hard you want it to be), you could combine the methods below in different ways:

For very large amounts of data (and permitting significant latency)

You write the data on some physical storage (flash chip, optical disc, future holographic 3D crystal matrix thing...), open a wormhole and hand/shoot/drop the medium through. It is then caught/received on the other end and read. Depending on the achievable size/frequency for wormhole creation, and of course the number of communication partners for one node, the process could be highly automated, with several storage media popping into and out of multiple tiny wormholes multiple times per second -- or maybe there's something about those wormholes that makes them a lot harder to create on the surface of a planet, and it requires a huge installation, and regular choices about which request for data transfer should be prioritized.

For smaller amounts of data, and much less latency

These days, wireless communication can be done via lasers (usually not in the visible spectrum, though): Effectively radio waves but coherent and directed, in order to focus the power needed to send and receive for a given signal quality. With a well-built communications laser/receiver, you would only need a millimeter-sized (or smaller) wormhole to start transmitting. During transmission phase, network speeds could be significantly higher than wired networks on Earth these days (extremely short distance, huge possible signal intensity, using shorter wavelengths than visible light). However, you can't always be transmitting since your wormholes collapse so quickly, and the higher the wormhole creation frequency, the smaller the holes, and the lower the throughput. So realtime communications could be possible, but would achieve fairly low data rates (or be very expensive).

Limiting factors

In a scenario where communications are more limited, you might also decide that creating wormholes on planets is pretty unfeasible/expensive, or has other negative consequences (radiation?), and therefore they could only be created in space, possibly at some safe distance to the machine what creates them. In that case, sending data from one planet to another might involve having a small wormhole created by a machine somewhere in orbit, and firing a communications laser through it (probably also mounted to the same machine, which receives requests for data transfers from the planet surface). This would mean no actual real-time communications unless you can pay for one of those machines to make tens of wormholes per second (to the same destination) and guarantee that your data packets will be prioritized.

Moving larger amounts of data via physical media would then also be harder because having some satellite to shoot the storage through wormholes, and catch/process what's coming back is way more involved than having them drop into some receptacle in your basement.

Some poor souls have to piggyback their communications through the big ships' wormholes, using the very short transit time to fire their communications lasers through the small part of the wormhole opening not blocked by the ship passing through it. There have been serious accidents because people used overpowered lasers and did not calibrate/aim them as they should have. That's why the practice is heavily regulated these days (read: so expensive that it's only a little cheaper than the alternatives). There's still some people who try to do this without a license, but it's dangerous for them because that kind of laser (and its origin) is quickly detected, and it's hard to make sure you're even hitting the correct receiver (and having the correct receiver in place) in such a short time frame. Yet, it's also the most secure way to send data if you don't want the transfer to be registered and logged, since all the other methods are being monitored (to various degrees in different systems, but you never know through which nodes your data will travel).

Potential technical issues

For some of the main planets/outposts etc., there would be fixed locations where the communication wormholes are created, and fixed schedules when which node is connecting to which other node. But if you're on a ship that is moving, potentially along a trajectory unknown to your would-be communication partner, that might be more difficult. Can you initiate communications with a moving ship if you don't know the c-hole (communications wormhole) coordinates for their receiver? Can you initiate contact with a receiver if you don't know its schedule? You might try to open a wormhole while it's trying to receive communications from some other place, and then the wormholes collide, which causes packet loss (possibly in a dramatic way?) and might cause other problems too. Maybe two simultaneous wormholes in one place are a very bad thing, so there would need to be strict administrative and technical measures to prevent that?

Either way, you would probably need to have a "handshake" of some sort to agree on coordinates/wormhole schedule before being being able to establish FtL communications. That means that a spaceship must maintain some sort of communications channel at all times, or they become impossible to contact at all. Except by local communications, of course, which requires a way of getting your message within the range of their sub-light receivers.

For an expedition to an uninhabited system, this would mean that losing their FtL connection would make it impossible for anyone else to reach them unless the expedition manages to reconnect to their base of operations, or you make a much bigger hole and push a communications satellite through (assuming you had one to spare...)

Logistics/organisation

If this is how interplanetary/-stellar communications work, I bet there would be a lot of bureaucracy, regulations, laws, and daily annoyance around it. Whoever operates these devices carries some responsibility, and that means that control of those nodes could (depending again on how hard they are to build and operate) play an important role in politics and economics. Companies/governments controlling and (mis-)using them, outlaws running their own, or some organisations/measures to ensure equal access to secure and safe communications (and the different degrees to which they succeed in that or abuse the trust put in them) could play relevant roles in such a universe. There would also likely be some communication routes much more popular than others, some wider than others, and some heavily contested/neglected ones. Almost like IRL, where some places get crazy glass fibre speeds but don't really use them, and elsewhere you pay twice as much and still can't have a phone conversation without standing on your kitchen table, so you end up purchasing a freaking expensive satellite link from the richest guy in the known universe...

Answer 9

Imagine you have a pair of drinking straws perfectly filled with beads the same diameter as the inside of the straw. Put a bead in one end of a straw, and the bead at the other end of the same straw will immediately fall out on the other side, with absolutely no latency.

This holds true no matter how long the straws are.

The problem is the longer the straw, the more energy you need to push all the raw weight of the intermediate beads, the stronger the straw itself needs to be, and the more energy (and heat dissipation) you need to fight friction from the straw walls.

For a sci-fi setting, you've probably already solved the energy problem. Most sci-fi settings at close inspection need an energy source that greatly outperforms what is available today.

Now you need to "invent" a particle you can use that will stay where you put it in a way that's largely immune to outside forces, and you can "push" as needed. It could be something very small, like a special not-yet-discovered variety of quark or sub-version of the higgs-boson. Of course, no such thing exists (that we know of so far!), but it's enough a lay person could believe a future civilization has worked it out.

So now we have a pair of particle "straws": one for sending, the other for receiving. At each end of the straw we have a station capable of rapidly pushing new particles in one "straw" and monitoring the changes in the other. Movement is a "1", idle is a "0", for whatever tick-rate your sensors/emitters are capable of handling, and now we have 0-latency digital comms.

A quirk of this scheme is the initial setup still has the full latency of pushing the first set of particles all the way from point A to point B, no matter how far apart they are, and you're likely limited by Einstein for this process. Between galaxies could take millenia. And if someone chooses to disrupt the flow, you may have your work cut out getting back in sync. But sometimes this kind of weakness serves the story as much as it hinders.

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To add one more point:

You don't have to explain yourself.

The very fact you've accumulated over a dozen answers means people are ready and willing to believe our future selves have solved this issue. Explaining it may do as much as harm as good, merely creating an opportunity to introduce a glaring technical error.

Answer 10

Use wormhole cables instead of fibre optics

Extending on Tom's answer here. Sending usb sticks over wormhole will cause huge latency.

If the world already has the technology to create wormholes, people can make use of wormholes to shorten the length of cable. One can send packets of light over the wormhole which will be captured by fibre optic device on the other end making it work as regular internet that we have today.

[PC on Mars]====(fibre optic cable)===:{ wormhole }:====(fibre optic cable)===[PC on earth]

For more thorough explaination, you can assign each Light Packet Transfer Wormhole(LPTW) unique id everytime a new one is generated, like IP addresses in our world. The generated IDs can be used to transfer data particulary from LPTW 1 -> LPTW 2.

Depending on the usecases for LPTW, we can divide it in particular ranges .i.e.,

1. Class A (interstellar priority links)
2. Class B (government and mega corporates)
3. Class C (SMBs and hobbiyists)
4. Class D (for individuals)

For IP address ref:

• https://en.wikipedia.org/wiki/IP_address

Update

I missed the part where wormholes are closing immediately. Thanks to Paŭlo's comment.

Even if the wormholes are closing almost immediately, the LPTW can still send a bunch of packets before closing down and open again with same ID. If the humans can pass whole spaceship through the wormhole, a few packet of light shouldn't be much of an issue.

Answer 11

Entanglement radio

I can't believe I forgot to post this, because it's something I use a lot. (I also think it's more fun than piggybacking on FTL travel.)

If two particles become entangled, changes made to one particle are applied to its entangled "twin," no matter how far away that twin is. Aspects that are propagated in this way include momentum, spin, and polarization.

So: you build a system where bits are transmitted by altering the polarization of an entangled particle. You keep one particle here, and the traveler takes the other particle with them, and now the two of you can send bits to each other.

I'm no expert in quantum mechanics, nor in information theory, but I imagine transferring a single binary bit could work in two ways:

• Model A: you use two sets of twins: one of the twins has its polarization changed to positive or negative to signal binary 1 or 0; the other twin has its polarization flipped once for each bit -- this is done to distinguish between instances of a single binary value being repeated. One particle marks out the "beat," the other particle sends the actual value.
• Model B: you use one twin and flip it in a rhythm (akin to Morse code), very similar to an old-school telegraph.

There are tradeoffs:

• Model A can send any sequence of N bits in a fixed amount of time, no matter what the actual bit values are, but it requires two particles (and thus a larger machinery footprint).
• Model B uses just one particle (and has a smaller machinery footprint), but the time it takes to send a sequence of N bits will vary based on the specific values being sent.

If you think it's really important to choose between the two models instead of just handwaving it, you'll need to decide how long it takes a machine to change the polarization of a particle, and how long it takes the receiving machine to measure the polarization. You'll also have to flesh out the picture of the machinery inside the radio, including how and where the particles are "installed" and what machinery must surround each to permit interacting with its polarization.

Either way, in the end you wind up with the ability to instantly transmit binary data point-to-point regardless of distance or direction.

If this sounds familiar, it might be because you know of Card's "ansible" device, which also permitted instantaneous point-to-point communication. (I don't recall whether he explicitly relied on quantum entanglement.)

Whenever I rely on this mechanism, I take it a bit further than Card did, and think about the problems and infrastructure that would arise around such a system. (To be fair, Card also had a much more interesting story to tell, which would not have been improved by adding depth to the ansible.)

• Bandwidth

  Whether you go with Modal A or Model B, nobody is going to limit themselves to just one (or two) twins, because that is pretty tiny bandwidth. No, you'll scale it up as far as is practical. I imagine that the hardware needed to read and write the polarity of an entangled particle is non-trivial, with a really great portable version being the size a large home refrigerator. I like to think that a single such "radio" might contain a couple dozen entangled particles, which is still not enough for a vessel to stream cat videos from home all day but should be plenty for the equivalent of naval dispatches (military and commercial) and other serious-minded communication, as well personal letters during downtime.

• Production

  I imagine it takes even bigger machinery to cause particles to become entangled in the first place such that they can be used in these radios, perhaps something on the order of the Large Hadron Collider. This means there won't be dozens of factories producing radios, but maybe just one or two, and those only on extremely well-developed planets. For a long time, Earth would be the only source. As a result, there will always be a shortage of radios, and moreso for high-bandwidth ones.

• Networks

  An entanglement radio can only communicate with its twin -- it cannot ever be reconfigured to communicate with a different radio. And the twin radios must be born at the same time and in the same place. This means you are never going to have a ship that can contact multiple sister ships directly. I think this means that the only way to have a system that permits two randomly-selected parties to communicate is for the home planet to keep one of every single pair! The entangled particles that stay on the home planet would not be placed into a portable fridge-sized machine like the twins that go abroad, but rather will be sent to a massive automated routing facility on the planet, which will function like a switchboard operator.

  Governments both honest and crooked will like this, because it means the vast majority of interstellar communication will depend on a very small number of hubs that they can control.

  Of course, this does not mean all communication must go through a hub. Governments will probably requisition special pairs of traveling radios for military and espionage purposes. I'd also expect them to set up their own private hubs, with a human-mediated link to the larger civilian hub.

  A pair of traveling radios could be unimaginably valuable to criminals and other folks with dark motives, so I would expect there to be a lot of illegal pressure on workers at the factory to secretly produce such radios; highly-placed individuals at the factory might be able to construct such things off the books, although those will all probably be low-bandwidth in order to fly under the radar.

  Over time, I would expect all major planets to exchange particles with each other, and these would undoubtedly be the largest-bandwidth radios ever produced, because the planet-to-planet links will form the backbone of the network. But, this will be a luxury that has to compete with more-pressing needs, and so I'd expect the backbone to grow in fits and starts as permitted by the needs of military and civilian fleets.

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The overall picture is one of a centralized galactic internet, with the links between vessels and planets having very small bandwidth, only a fraction of the speed of the slowest real-world telephone modems.

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One thing to note is that I've always assumed that particles could only be entangled in pairs, and that fact shaped the design of this system. Reading up on things today, it sounds like a whole group of particles could become entangled with each other. The situation I've sketched out here has been rolling around in my head for a long time, and I'm sorry to say I haven't had time to revise it in light of this new information. If you find this useful, it may be easier for you to do that yourself.

Answer 12

In the Wing Commander universe they sent drones.

You could have a space station or satellite in orbit populated with drones, where you send the transmissions to. The satellite would then load a drone with the transmission, and then propel the drone to a wormhole generator which sends it through to the target, where the drone wirelessly transmits the data from orbit (and is recaptured and refuelled by that stations drone communications center) - this would allow for low-lag communication, still superluminal, but not real time, and not as laggy as even inter-system communications would be

Answer 13

This depends on how these wormhole thingamajigs work. If it's an all-or-nothing thing, then you have a hole specifically for data, and specially designed crafts receive light-speed data and, on a schedule, hop through and re-transmit that data to other waiting ships, hop back, do it again. If you send ships through it once per minute, you're getting far less latency than even interplanetary communications.

But maybe your wormholes are a bit more subtle. Maybe you can just slightly open one, or just perform a pre-opening pulse. Let's say you have a laser passing through the area that the wormhole is directed at, and can read the deflection of the laser as a signal. Now you have an intergalactic fiber optic.

The boring way would have small permanent wormholes with a cable passing through it. yawn

Answer 14

Entangled photocopying

There are two photocopying machines, one over there and one over here. Each 20 minutes, a copy is done (or not). Both machines inject one beam of previously entangled photons onto the paper. On our side the photons will reflect and change state, on the other side they will only change state. Which can be detected, the information used to print the document.