Do electromagnetic waves ever stop,dissipate where they cease to exist forever?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Gravage, Sep 21, 2005.

  1. blobrana Registered Senior Member

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    2,214
    The principle that things keep moving forever in straight lines unless acted upon by something else is wrong?

    As Richard Feynman once said “If it does not fit with observations then it is wrong”…


    In this case, the real life application of that principle <b>is</b> `comparable`.
     
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  3. MetaKron Registered Senior Member

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    Wave interference does not create or destroy energy. It creates deeper troughs but puts the energy into higher peaks.

    802 type wireless ethernet links can work over more than 6 miles with a parabolic antenna on the subscriber computer and an omnidirectional antenna on distribution side. I've seen it done.

    An interesting thing is that the further electromagnetic radiation goes the further it has to go to lose the same percentage of signal strength. A signal loses about 172 decibels from the Earth to the Moon, and another 172 coming back depending on the kind of reflector. That's 344 decibels down from the one meter distance. The same signal loses 260 decibels traveling one light year. From one light year to one billion light years the loss is 180 decibels, for a total of 440 decibels lost. From there to a hundred billion lightyears is another 20 decibels down. For any distance that we think even might exist, a readable signal still exists. We have radar installations that can distinguish large surface features on the moons of Saturn.
     
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  5. Gravage Registered Senior Member

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    So,what does it mean,MetaKron?
    Does it mean that signal strength and the radio-wave strength can lost,dissipated,destroyed(call it whatever you want)?
    Let's suppose this:Seti sends message to aliens,but how do we know that signal or radio-wave strength will get to the aliens?
    I mean quasars are extremely powerful mediums,so they can send radio-waves at enormous distances without losing signal strength?
    So,what do you think MetaKron,can the signal strength be weak enough that it simply get destroyed,dissipated forever?
     
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  7. RoyLennigan Registered Senior Member

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    no it cannot be destroyed, but it will weaken over distance as he was saying, and it can also be deflected by matter in the way.

    quasars lose signal strength too, at the same rate any other radiation loses strength, what makes you think they are any different?

    and no, the signal strength decreases at an exponential rate, so it will infinitely decrease, but never reach zero.
     
  8. Gravage Registered Senior Member

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    1,241
    What makes you think energy is undestroyable,even energy vibrates.
    Also,waves sooner or later should lose their energy after some time,much like your car loses gas,and once it will stop,you need to re-fuel to start driving again,the same goes with radio-waves...
     
  9. Gravage Registered Senior Member

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    Also,when you have 2 approaching waves one opposite of the other,and let's suppose these 2 upcoming waves have exact quantity of energy,what do you think will happen,they would annihilate each other,and there would be no energy left of their collide.
     
  10. RoyLennigan Registered Senior Member

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    1,011
    uh... the law of conservation of energy. ever hear of it? apparently not.
    energy is not lost, it is just deflected by particles in space like a mirror deflects light. but no matter what, some of that energy will keep travelling in the original direction, so no, it is not like the gas in your car.

    the two waves deflect each other and the particles go flying off in different directions. with a direct hit between two particles, they will break down into other particles. search for information on particle colliders to confirm this.
     
  11. Gravage Registered Senior Member

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    1,241
    Oh,thanks for the help!
    And yes I know that conservation of energy.I was just kidding.Also,over these last 200 years in any kind of experiments that was done scientists couldn't destroy and recreate energy.
     
  12. CANGAS Registered Senior Member

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    1,612
    Maybe it will. And maybe it won't. Why do you want to know? We find your curiosity very interesting. There is no empirical evidence that the universe is limited or unlimited. There is no theoretical basis, according to current mainstream physics ideology, to extrapolate that an unrestricted photon ( one which never becomes absorbed into a lonely electron or other particle ) would ever vanish.
     
  13. Starman Starman Registered Senior Member

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    540
    http://www.stardrivedevice.com/powe...RAW=overunity&OVKEY=over unity&OVMTC=standard

    Therein hangs the problem. Experimentally we know that (i) the input energy to the source charge must be in virtual state form, and (ii) when we produce a charge suddenly, the fields and potentials are created at light speed outward in all directions. Once they reach a distant point and pass beyond, the fields and potentials and their intensities at that point are also continuously maintained thereafter, showing that a continuous emission of real energy from the source charge is occurring so that the static fields are continuously replenished in place—precisely like Van Flandern’s waterfall analogy {8}.

    http://www.cheniere.org/techpapers/vanflandern.htm
     
    Last edited: Oct 10, 2005
  14. MetaKron Registered Senior Member

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    5,502
    The language you use is imprecise, but there is a certain amount of dust and gas between here and there, wherever there is. Some of the signal can be absorbed, but widely spaced gas and dust is extremely poor at absorbing radio signals. If you are thinking of extreme distances like billions of light years, it would do you some good to look up the basics about signal strength and radio astronomy. We know that a signal will reach a given area because we can estimate its strength with great precision. Radio astronomy has given us an idea of how much signal is lost. We already know that radiotelescopes can "see" through dust clouds that scatter light.

    The energy of a signal cannot be destroyed, but it can be absorbed or scattered. If you send a laser signal, it's not going to make it through any dusty regions. Millimeter waves will.
     
  15. Gravage Registered Senior Member

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    I think energy wouldn't be destroyed even in any other universe with different laws of physics since how could this other universe,with different laws of physics,exist without the energy.The would mean that energy is truly undestroyable since every universe would need energy for "staying alive".I don't think energy could be destroyed even if this universe isn't a closed system.
    Hmmm...
     
  16. Gravage Registered Senior Member

    Messages:
    1,241

    Yes, and this is what I've been trying to ask you:Could the signal's integrity,after being completely scattered billions of miles away lose the information it carries(because signal loses magnetic field which contains and supports information's integrity-if information loses that integrity;and that happens when there is no magnetic field-example much like an picture and sound is stored on the magnetic field of the video-tape or television)?

    What than happens with the information who was in that electromagnetic wave-it doesn't exist anymore or it gets absorbed into other electromagnetic field which "saves" the integrity of the information inside,or information truly doesn't exist anymore(when I say information,I mean sound,pictures,music that are oftenly sent to space)?
    I wonder if scientists know the answer on this question?
    Hmmm...
    Does anyone knows any website which could help me to understand this thoroughly?
    Thanks for your patience!
     

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