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Working on the rough draft of a novel, mind if I ask some...

  1. Jul 9, 2016 #1
    I'm working on a science fiction novel, so feel free to ignore reality if you bother to answer this.

    In my book (rough draft) I was using laser beams to transfer data. Essentially imagine a relay of nodes between the earth and Mars. Each node contains at least one (and probably more) laser beam and a receiver. The laser simply points at the next node in the relay, like a network, and data is transferred from point to point like fiber optics without the fiber.

    So here's the thing, I was wondering how to power this contraption snd since this is completely sepeculative, began to imagine, instead of laser light, a focused beam of either hydrogen or helium atoms. Suddenly I was imagining binary being accomplished with neutral atoms being equal to zero, and ions being equal to ones. As an added bonus the stream of atoms could be used as a power source.

    So, here are my questions:

    Imagine a beam of Hydrogen atoms. How fast could these travel? The advantage of a laser is that it goes the speed of light. But a single atom of Hydrogen doesn't weigh much, and could probably be excellerated a lot. I think.

    How much would solar winds affect my beam?

    Is a beam of Hydrogen travelling in a straight line over long distances even hypothetically possible?
     
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  3. Jul 9, 2016 #2

    malawi_glenn

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    How to accelerate neutral atoms?
     
  4. Jul 9, 2016 #3

    Drakkith

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    Using a laser is almost certainly MUCH simpler and MUCH more efficient than trying to accelerate atoms/ions. For one, you don't need a supply of atoms with a laser, which means you don't need a lot of extra equipment to capture the sparse solar wind. Accelerating ions to a very high velocity takes a LOT of power and a large acceleration distance. This vastly increases the size, cost, and complexity of your communication satellites. As for power, standard solar panels would be adequate. The Juno probe, which just arrived at Jupiter, is using solar panels, and I would expect their cost to decrease and their efficiency to increase in the future.
     
  5. Jul 9, 2016 #4
    Yeah, that's what I had thought. But my Mars example was a simplified example. The idea was to build brudges between this solar system and Alpha Centauri or Proxima Centauri by deploying thousands of chains of astroids from the kuipier belt, to pass data between them. I was worried that in deep space there wouldn't be enough sunlight for solar power.
     
    Last edited: Jul 9, 2016
  6. Jul 9, 2016 #5

    Drakkith

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    At that point you're probably better off using some other source of power like an RTG or fusion reactors or something.
     
  7. Jul 9, 2016 #6

    DaveC426913

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    Why do you need relays though? Every extra relay is a point of failure, both mechanical and ... data-al. And it needs power and maintenance
    Why not just ensure the laser is powerful enough to reach the destination? Now all you power, maintenance and data integrity issues are housed where the people are who operate it.

    Though granted, it kinda rains on your whole idea...
     
  8. Jul 9, 2016 #7
    Well I am going to have some big lasers, some medium distance ones, and a hell of a lot of smaller ones. I'm not sure that bigger single laser communication set up would be able to work. It is the volume of data that I'm concerned with.

    Basically I've got virtual reality world where most of the population is digital. If they want to "go outside" into the non-computerized world they can clone themselves and then transfer their consciousness into a custom grown clone. So what I am doing is creating a network that would be the main thoroughfare between this solar system and the nearby ones. Lots of data streaming back and forth.

    So I'm not sure if big lasers could handle that level of volume, it might work for a single route, or really multiple single routes. But chain relays of nodes, instead of waiting 10 or 12 years for the round trip to find out if the data made it intact, a relay could self correct every say ten minutes. I worry about bigger lasers if something shifts, like a comet passes in front of the receiver, or if a solar flare causes the receiving satellite shifts because of a solar flare.

    You could bypass a broken node by aiming at another node a couple down the line, or if there are parallel paths between them, send data back and forth. If something broke along the way, you could just clone a body at the node and perform maintenance directly a the problem, or just send an AI.
     
    Last edited: Jul 9, 2016
  9. Jul 9, 2016 #8

    DaveC426913

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    Why not? Giant lasers are at the heart of most proposals for interstellar solar sail ships.

    The great thing about optical communciations is that they have a MUCH higher data rate than other systems.
    1] You can have as many channels as distinct frequencies. Which is a lot.
    2] EMR takes up no room.You can send all signlas thorugh the same volume without ever having any of them interdere.

    Lasers are your bst option.

    They will be better than any other options.

    Ah. Now I see your point.
    If there were a failue in the forst leg of the journey, you would not know it until the return signal.
     
  10. Jul 10, 2016 #9
    Plus wouldn't it be like a sniper firing a rifle and hitting a quarter four or five miles away. You might be able to build a laser that was capable of shooting that far, but the the amount of calculations to hit a moving target light years away I suspect would be astronomical.
     
  11. Jul 10, 2016 #10

    Drakkith

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    Nah. A laser beam spreads out as it travels. A small laser beam pointed at the Moon would be miles across by the time it reached the lunar surface. See here and here for more info.
     
  12. Jul 11, 2016 #11
    Hmmm. Interesting. I wonder if there would be a way to tighten up and lessen the divergence. Would a laser using a different type of photon work better? Say a Gamma ray laser with really high energy and a really short wavelength? Or would a longer wavelength work better, I am reluctant to use radiowaves, but maybe I'll have to
     
  13. Jul 11, 2016 #12

    Drakkith

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    Shorter wavelengths suffer less divergence than longer wavelengths, so you are correct that a gamma ray "beam" would lessen the divergence. It's also MUCH more difficult (impossible at this point in time) to create and does a poor job at communication since the energy per photon is so high (a 5 MW gamma ray laser will produce thousands or millions of times fewer photons than a visible light laser). With fewer photons your system will suffer from dramatically increased noise and loss of signal. Shot noise becomes extremely prevalent and will likely become the dominant source of noise.

    You could make the beam larger before focusing it. You can use lenses or mirrors to make a small diameter laser much larger, and this much larger beam will suffer less divergence as it travels. Of course this means you need lenses and mirrors of that same diameter, which can be heavy and costly.
     
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