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Does ether exists?

  1. Mar 1, 2010 #1
    During the 19th century, it was proposed that light travels through vacuum in the presence of a pseudo medium known as ether. But does it really exist? Is there any evidence whether it exists or not?
     
  2. jcsd
  3. Mar 1, 2010 #2

    Dale

    Staff: Mentor

    No. There is no evidence that it exists.
     
  4. Mar 1, 2010 #3
    I've often wondered if String Theorists consider spacetime as an ether of sorts. I guess it's a pretty irrelevant point regardless.
     
  5. Mar 1, 2010 #4
    Is there any experimental proof that it doesn't exist?
     
  6. Mar 1, 2010 #5

    Dale

    Staff: Mentor

    How would you conduct such an experiment? If you can describe the experiment you are looking for then someone on this site can probably tell you if it has been done.
     
  7. Mar 1, 2010 #6

    DaveC426913

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    The experimental evidence that it doesn't exist is that there is no evidence that it exists. That and the fact that the physics of EM radiation works perfectly fine without it.
     
  8. Mar 1, 2010 #7

    fluidistic

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  9. Mar 1, 2010 #8

    mgb_phys

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    Ether certainly exists
    Aether on the other hand doesn't
     
  10. Mar 1, 2010 #9

    fluidistic

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    According to wikipedia, Luminiferous aether is also called "ether". Now if you ask me a scientific reference, I run away!
     
  11. Mar 1, 2010 #10
    The ether doesn't exist but you could be forgiven if you called it dark energy, or the quantum state or perhaps quintessence, not exactly the same but certainly sharing some of the same properties as the 19th century aether.
     
  12. Mar 2, 2010 #11
    If an aether existed the planets would not keep orbiting they would slow down.
     
  13. Mar 2, 2010 #12

    jtbell

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    Which to my mind is like calling a horse a hippopotamus because they share some of the same features. :rolleyes:
     
  14. Mar 2, 2010 #13
    I just wonder why you think so? If there existed an aether, then one of its most significant features was that it was considered massless so no transfer of momentum could contribute to a slow down.
     
  15. Mar 2, 2010 #14
    'Hippo' means 'river horse' in Greek so not too different really.
     
  16. Mar 2, 2010 #15
    A photon has no mass but it has momentum and it can transfer momentum , like in laser cooling .
     
  17. Mar 2, 2010 #16
    The photon has a frequency which is the bit that relates to its momentum (I think that's right). The 19th century aether was considered as not having a frequency . Perhaps Tesla thought it did but in general I think he was an exception.
     
  18. Mar 2, 2010 #17
    well doesn't everything have a frequency , and we are talking about something that doesn't even exist.
     
  19. Mar 3, 2010 #18
    No not everything. The field round a magnet for instance. Einstein's 'spacetime continuum' :smile: the non existent aether to name but a few.
     
  20. Mar 3, 2010 #19
    so your implying that gravity is continuous and magnetic fields are continuous and not quantized.
     
  21. Mar 4, 2010 #20
    Yes - but to be honest, I'm not really 100% sure about magnetic fields.
     
  22. Mar 4, 2010 #21
    Interesting
     
  23. Mar 4, 2010 #22
    No there is no such experiment,its just theoritical hypothesis
     
  24. Mar 6, 2010 #23
    There is evidence that ether exists. One such evidence is that so-called empty space has properties. Even Einstein acknowledged this. His point was not that ether didn't exist but rather that the concept wasn't needed for calculations!

    However, without ether, one has some rather severe philosophical conundrums. Maxwell pointed out that there are really only two ways for energy to be transmitted from place to place. One way is kinetically. In other words if I shoot a beam of particles or bullets or baseballs through space, I can transmit energy from place to place. And note that this can occur through totally empty space (except for the projectiles, of course). On the other hand the other way energy is transmitted is by waves! Light, radio, sound, ocean waves all transmit energy from place to place. But Maxwell noted that such transmissions REQUIRE a medium for the waves to propagate in. Modern physics assumes waves propagating with no medium at all. Modern physics assumes that nothing at all can have properties (empty space). None of these assumptions create any kind of logical system. In the old days, the problem was solved with a hypothetical material to transmit wave energy known as "the aether".

    But before we get too excited we should note that light, for example from modern experiments does not seem to be a wave at all. Indeed, it doesn't show the properties waves are known to have with respect to several observations such as the time necessary for energy transfer. Detectors easily show individual "photons" that make up a light beam formerly thought to be a wave. And yet statistically if you have LOTS of photons going through slits etc, one finds the statistical patterns obtained are solutions to the wave equation! It's all sort of a large mystery. Thus it is clear that the 19th century idea of light as a wave in the aether is not correct. Now that doesn't eliminate the concept of an ether, but does indeed mean that the old standard versions are in serious need of revision.
     
  25. Mar 6, 2010 #24
    Michelson/Morley failed to detect aether WIND with their experiment. Failing to find something does not necessarily mean it does not exist. It maybe the equipments used was wrong or they started on a wrong premise, like trying to measure the speed of a rail track. Nonsense!
     
  26. Mar 6, 2010 #25
    My analogy is simple you may rightly dismiss me as simplistic. Think of a block of dry ice that can somehow sublime slowly at one end cigar like and form slowly at the other end. To an independent observer it will seem that the block of dry ice is moving. Now that is how you, me, your car, airplanes, space crafts, electrons, photons and pretty much everything else moves in aether. For this analogy carbon dioxide is the aether.
     
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