Does space has a resonance frequency?

Discussion in 'Off-Topic' started by 4beowulf7, Jul 27, 2015.

  1. 4beowulf7

    Thread Starter New Member

    Jul 25, 2015
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    Hello everyone!
    As we all know, the supposedly empty space has a non-zero permittivity (eps) and permeability (mu). If you do the math, the speed of light in empty space can be derived from these two constants.
    If we apply those constants to the formula of resonance frequency ( f=1/(2*pi*sqrt(L*C)) ) by placing permittivity as the inductance (L) and permittivity as the capacitance (C), we get 47713957.66 Hz or about 47.71 MHz.
    I wonder what might happen if we transmit a signal exactly at this frequency. Will it be amplified or attenuated or nothing happens?
    Just an idea and wanted to share with you.
    Greetings
     
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    If you transmitted at that frequency. Exactly 47.71 MHz. The entire universe would begin to contract and the world as we know it would end. Oh, please don't do it! No one has EVER transmitted a radio signal at 47.71 MHz before.

    (kermit makes a quick trip to his user settings page and the pain disappears.) :)
     
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Why would you apply them to that formula?
    If I apply them to the formula E=I*R, where I=eps and R=mu I get something equally non-consequential.
    If I apply them to the formula for sugar, C12H22Oll, where C=eps and H=mu, I get a totally new compound!
     
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  4. Glenn Holland

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    Dec 26, 2014
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    Free space has permittivity for electric and magnetic fields, but it does not have any inductive reactance or capacitive reactance.

    Space has an extremely broadband transmission characteristic for everything from infrared to gamma radiation, however there is no possibility of creating an LC oscillator or resonance.
     
  5. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    Space is not reactive (the electric and magnetic fields are in phase at all times in free space), space is resistive but not dissipative, it is dispersive.

    There are energy levels in vacuum where fields are expected to be nonlinear. Schwinger limit but like most things it's on the 'outer limits' of what's possible.
     
  6. GopherT

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    Nov 23, 2012
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    I've never used that feature before. Handy.
     
  7. Glenn Holland

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    Dec 26, 2014
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    As a point of info, electromagnetic waves in free space (or any substance which is transparent to EMWs) are always 90 degrees out of phase just like in a table top oscillator. However, EMWs in free space are not attenuated and they can travel an infinite distance.

    As the TV comedian Johnny Carson once said on the Tonight Show, "It's really gratifying to know our conversation is endlessly going into the depths of the universe".
     
  8. nsaspook

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    Aug 27, 2009
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    Just to be clear that's not the phase angle relationship leading or lagging as they travel in space, they oscillate in phase. The Electric and magnetic field vectors are 90 degrees out of phase.
     
  9. 4beowulf7

    Thread Starter New Member

    Jul 25, 2015
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    The units of permittivity and permeability are Farads/m and Henry/m, respectively. So, as if, the space exhibits a distributed transmission medium with a capacitance of eps and inductance of mu, per unit length. That's why I placed eps as C and mu as L in the resonance formula.
     
  10. Papabravo

    Expert

    Feb 24, 2006
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    You can't just place something with units that are close to what they are supposed to be and expect it to be meaningful.
    Frequency has units of (1/sec, or reciprocal time). When you introduce distributed parameters you get units of length involved which leads to nonsense. Instead of pontificating nonsense, why don't you engage in some self study or take a class and stop wasting time and energy on off the wall fantasies.

    Just to whet your appetite for things which are real. Free space does have an impedance and it related to the two constants you are so fond of:

    https://en.wikipedia.org/wiki/Impedance_of_free_space
     
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  11. Lestraveled

    Well-Known Member

    May 19, 2014
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    Guess what an antenna does? It matches the impedance of your transmission line to the impedance of space. The world (space) is a transmission line.
     
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  12. Papabravo

    Expert

    Feb 24, 2006
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    And, TV shows from the 1950's continue to travel through interstellar space.
     
  13. tcmtech

    Well-Known Member

    Nov 4, 2013
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    Well sort of. In ideal dead space they would just like a stone thrown in a perfectly still dead calm ocean would make a detectable wave on the other side of the planet but in reality they are more like ripples in pond on a breezy day.

    It does not take very long or very far in galactic/universe space and time referenced values before the tiny waves we made are drowned out by all the other natural background EM waves and noise making them impossible to detect just like how a radio or TV transmitters signal becomes too weak to differentiate from the noise of nature on the same frequency bands.

    I don't recall the exact estimated distances involved but the biggest transmitters we have ever constructed were likely to only be detectable against the background noise of the local galaxy out to a few tens to maybe 100 or so light years given the estimated natural noise of the local galaxy Vs the rate of signal decay. :(
     
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