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Bandwidth of space

  1. Aug 31, 2010 #1
    Bandwidth of space!!!

    Can anyone tell me what might be the bandwidth of a m3 of space or air.
    As we can tell the b/w of Cu wire is in MBps , ethernet cables in GBps and that of optical fibre is around TBps ; is there any way to find out or any formula to calculate the threshold capacity of the space or wireless medium for holding various data in EM-waves of various frequencies.

    We all know that in a single room we can tune into 100s of short waves, AMs, FMs using a radio. In the same room we may use mobiles of different operators . Similarly in a same place we may use satellite disk to capture numerous TV stations and many more communication devices. So it means that the same room physically contains em-waves in thousands of number- we can separate them or tune into them using different electronic devices.

    I am thus wondering if space has some limit to hold EM-waves. EM waves has always amazed me a lot and I still do not understand how do they actually propagate.

    I have heard for many times that the b/w of space is near to infinite and as we see, it is so.

    But some us may still think that there must be some critical point or wave threshold of the space after which it breaks down.

    I am looking forward to having your opinions.
     
  2. jcsd
  3. Aug 31, 2010 #2
    Re: Bandwidth of space!!!

    If you were to put an abolutely rediculous amount of electromagnetic radiation in one place, it will turn into a black hole. So that's one limit.

    Another limit would probably involve quantum effects (HUP).
     
  4. Aug 31, 2010 #3
    Re: Bandwidth of space!!!

    That was one interesting point you made. So, do you have any idea about what may be the reasonable B/W of 1 m3 of space or do you think there could be some formula to calculate it?
     
  5. Sep 1, 2010 #4
    Re: Bandwidth of space!!!

    I'll give it a shot over the weekend, should be fun!
     
  6. Sep 1, 2010 #5
    Re: Bandwidth of space!!!

    https://www.physicsforums.com/showthread.php?t=196160
    Been there, check the papers in post #2
    Bandwidth is not an entirely accurate term in this case
    Fundamentally there are only 2 analogues:
    Storage capacity -> Volume of space
    Processing power -> Energy of system(what you are looking for - ability to move information at speed)
     
  7. Sep 1, 2010 #6
    Re: Bandwidth of space!!!

    The antennae of the receivers/transmiters are the biggest hindrance of the b/w. Also, EM radiation cannot create black holes.
     
  8. Sep 2, 2010 #7
    Re: Bandwidth of space!!!

    Matrix, way to kill my fun.

    Are you SURE about that?
     
  9. Sep 2, 2010 #8
    Re: Bandwidth of space!!!

    No, but all I know is that EM fields do not contribute to the scalar curvature of spacetime because the trace of the stress-energy tensor is zero for them.
     
  10. Sep 2, 2010 #9
    Re: Bandwidth of space!!!

    Are you sure about THAT?

    EDIT: Even if that was true think photon-photon particle production.
     
  11. Sep 2, 2010 #10
    Re: Bandwidth of space!!!

    To be perfectly honest, I don't know and I don't feel like hijacking his thread.
     
  12. Sep 2, 2010 #11

    alxm

    User Avatar
    Science Advisor

    Re: Bandwidth of space!!!

    Even if there was some meaningful answer to the question 'how much data can air hold', determining the bandwidth would still require the air (or something) to be moving.
     
  13. Sep 2, 2010 #12
    Re: Bandwidth of space!!!

    In the high frequency end, when photon energy and density are insanely high, it is believed that colliding photons may produce pairs. Since vacuum cannot be perfect, stray atoms can allow pair production by a single photon. So the limit to this end would depend on local vacuum conditions (the kind of atoms and their numbers).

    In the low frequency end, I don't believe there are any theoretical limits.
     
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