Transmission information capacity

Sarpedon · Aug 20, 2008

Would it be possible to transmit information of the equivalent size of the traffic of the internet through space?

I kind of got the idea that if humans were going to colonize another star system, what sort of things would they do to keep in touch with Earth? Naturally, they couldn't write e-mails, because there'd be at least at least a 10 year round trip (I was thinking 20 for my purposes). So there couldn't really be a direct interpersonal communication. However, people on one planet could write the equivalent of a blog, and people on the other could read it (5 or more years after the fact), while also keeping up on music, fashion, not-so-current events and so forth on the other world.

The only limit to this would be the capacity of a carrier beam, and the energy required to transmit. (assuming the governments of both worlds felt that continuing cultural contact was sufficiently important to go through the effort) Does anyone have any insight into how this would affect such communication?

RJK · Aug 20, 2008

I don't have the answer to your question but there are other things that would need to be considered. Both transmitting stations would have to be in space, possibly polar orbit, so they would always point at each other's planet. The bandwidth would have to be considerable but it would be doable. If in space, the transmitters could be solar powered, therefore, other than the capital expendatures, the power is free.

I suppose it would depend on the atitudes of both societies. If we were depending on our society, today, forget it.

FinbarReilly · Aug 22, 2008

With a 10+ year trip, it's simply not going to be feasible to keep up on anything current (like fashion), and about all your going to probably see are news feeds, with an emphasis on big events and technology.

More to the point, you're not going to be able to do even a significant part of the internet, nor is there going to be any real purpose; too much on the internet is transitory or requires an immediate response (could you imagine the necromancy that would go on?).

If you do want an interstellar internet, I would advise coming up with a better system, such as an ansile or quantum entanglement. Even noetic teleportation (use of psychic abilities to teleport) may be useful....

Good luck!
FR

dpaterso · Aug 22, 2008

Just one example from the Sci-Fi universe: Larry Niven's colonies in his Known Space novels and stories use high-powered communication lasers to send constant streams of news and other traffic (including novels!) to each other. Consider the amount of data a tiny optic fibre cable can handle. Now up the scale to a 36-inch aperture x-ray laser. Sure, the light beam will take years to get there, but it will get there (ditto the replies coming back). Once lasers are in orbit and pointing at Epsilon Eridani 67 or wherever, there's no reason not to use them continuously and open them up for personal traffic, you'd never max out the bandwidth. We associate email with instantaneous communication but before the internet -- heck, before modern transport and a regular postal service came into being -- people wrote letters. Why wouldn't they go back to doing that? The idea that cultural connections wouldn't be maintained, especially when cost and technology are a long way from prohibitive, is slightly boggling.

-Derek

RJK · Aug 22, 2008

Derek has a point. 200 years ago, a transatlantic or transcontinental post would take months, even a year or more if the recipient was living on the fringes of civilization.
They still communicated with the folks back home.

hammerklavier · Aug 22, 2008

Current space probes use radio to transmit information and that's probably the best way. I think your idea is completely feasable, but you'd probably want multiple satellites sending and receiving the information and duplicate channels of the really important information. Computer encoded information can be sent over radio, it would sound like a bunch of static to the human ear.

Sarpedon · Aug 22, 2008

Sure they wouldn't be able to keep current with fashion, but they'd be able to see the fashion of 20 or whatever years ago. Thats kind of one of the interesting plot points that this would lead to; Imagine a character who every day listens to the radio from earth (and when I say radio, I mean it gets bundled with everything else, transmitted, received by the local receiver, unscrambled, sorted, and retransmitted locally), with all the 'latest' hits, and reads technical manuals, 'news' stories and all sorts of stuff from Earth, giving him an illusion that Earth is near. Then a crisis happens in his star system, that changes everything in his life...but the earth transmissions go on unchanged; it will take 20 years for them to register the change. Suddenly the character feels very alone and isolated.

I don't feel that they would write letters with a 10 or 20 year turn-around...especially because the initial colonists would have been frozen for a century or more to get there, so no-one they know is left. I think it would be difficult to maintain an interpersonal relationship when it takes so long for the other person to react to what you are saying.

But thats a very interesting philosophical point.

Of course, there's no reason to think that people wouldn't live longer...except that the character I have in mind lives on a space station and gets high doses of radiation constantly.

Oh, and when I said 'internet' that was just an idea of how much information would be going to and fro, not how it would be used. (though I think the idea of interstellar blogs would be interesting) Most of it would probably be scientific data, plus records and stuff.

But thanks for all the views guys, its been helpful.

FinbarReilly · Aug 23, 2008

dpaterso said:
=The idea that cultural connections wouldn't be maintained, especially when cost and technology are a long way from prohibitive, is slightly boggling.

-Derek

Not that boggling if you are using a laser: There is the minor issue that the turnaround time is going to be ludicrous; we're not talking a matter of months here but of decades. Also, you're making the assumption that you can keep that thing on target for any amount of time, and that nothing will interfere with the signal (there is the Oort cloud around the solar system, for example). And then there is dissipation of the beam itself over distance.

Obviously a laser system is not going to work if you are trying to set up a system that hard science fiction fans aren't going to laugh at. Radio is pretty much what you are limited to, barring some slightly more fantastic system (even though time and dissipation may remain issues).

FR

Priene · Aug 23, 2008

I'm having difficulty imagining radio signals that wouldn't degrade over light-years, and similarly with lasers, well, if we can't (with current telescopes) directly see any planet in different solar systems, I don't see how we'd be able to identify information from lasers or radios fired from a planet. You could have booster stations, I suppose, loads and loads of booster stations, but they'd all need power and if one ten light years away went down you wouldn't know about it for twenty years and then you'd have send an engineer out. And you know how grumpy these engineers get having to spend half their working lives on one minor call-out....

What I can imagine is that when new ships arriving at a colony (don't know whether hyperdrives are allowed in your universe), they'd probably be carrying a copy of the internet with them. The colony would slowly fall out of touch and then get updated all in one big splurge. Colony scientists, engineers and entrepreneurs would get pretty excited each time a ship came to call.

Although, on second thoughts, these SETI people search for radio waves from other planets, so they must thought this through. Mind you, there's a big difference between blasting one "hello world" message at the universe and sending off gigabytes worth of recoverable data.

dpaterso · Aug 23, 2008

FinbarReilly said:
Not that boggling if you are using a laser: There is the minor issue that the turnaround time is going to be ludicrous; we're not talking a matter of months here but of decades. Also, you're making the assumption that you can keep that thing on target for any amount of time, and that nothing will interfere with the signal (there is the Oort cloud around the solar system, for example). And then there is dissipation of the beam itself over distance.

Obviously a laser system is not going to work if you are trying to set up a system that hard science fiction fans aren't going to laugh at. Radio is pretty much what you are limited to, barring some slightly more fantastic system (even though time and dissipation may remain issues).

Well, yes. But (within the context of this discussion

)...

If you're stepping up technology to a point where travel to other stars becomes possible (at present time, it isn't... even a journey to Mars isn't do-able with today's tech) -- and freezing human beings for the journey then thawing them out alive at their destination becomes possible (ditto) -- then it's feasible to envisage a future with big pulse laser cannons in outer space (heck, Reagan authorized this program's development back in the '80s) with virtually unlimited power supply -- that big bright thing we call The Sun

-- capable of punching holes through the ether. Radio signals have to compete with the overwhelming mush of the cosmos, bombarding from all directions, whereas lasers can be ramped up and hardened. Tho' you'd *want* a spread at the receiving end so there's far more chance of the signal being received. Fine tuning would occur throughout the journey, with the lasers pinging the colony ships. Either way, it's going to be cheaper and faster than sending a mail boat, 'cause I'm still having problems imagining why a colony wouldn't want to hear from Earth and/or Earth wouldn't want to keep in touch with a colony, no matter how long it takes to receive a reply.

-Derek

Priene · Aug 23, 2008

It's one of these things engineers probably would work out how to solve. There's too much riding on it, and too much profit to be made, for someone not to work out a way.

I'm thinking hyper-efficient compression algorithms would be in the mix somewhere. Rather than send the information, or even standard compressed information, you send a mathematical equation describing a complex line where you can decode information by looking at the points a line passes through. Deriving the equation for a given set of data, would be the tricky part, but once you've solved that process, you'll have massively cut down the amount of data needed in sending the message.

(and, of course, it doesn't have to be true, it just has to sound plausible)

Transmission information capacity

Sarpedon

RJK

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FinbarReilly

dpaterso

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RJK

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