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I How would the sky look if ether drag hypothesis was true?

  1. Oct 8, 2016 #1
    I just learnt how stellar abberation and the ether theory while studying Robert resnick's book. What I'm thinking is how the sky would look IF ether were to exist and be dragged along the earth as it revolved the sun. Since earth's local supply of ether is moving along with it i.e. rest w.r.t the earth shouldn't it behave like a giant layer of refractive glass over the earth? Since any light falling on it(the surface of ether layer surrounding earth) say from an angle 30° to the overhead would be propagated directly along the normal or very close to normal to maintain light's speed C wrt to earth's ether. Because if it didn't bend the light then due to earth's motion around sun (V=30 Km/s) we would see an additional speed being added ( I guess V cos 30° will be added to C and resultant will be sqrt(c²+V² cos ² 30°)) to the light ray which is would be inconsistent with the the original hypothesis itself. Is the analysis OK? Or more importantly is stellar abberation definite proof for dismissing the ether drag hypothesis? If ether drag did exist then would there be no stellar abberation?
  2. jcsd
  3. Oct 8, 2016 #2
    In order to answer your question you will need to endow your "ether" with some physical properties. Have you considered what they might be, for example by what mechanism is the ether "dragged"? What optical properties might it have? What experiments would you propose to measure them?
  4. Oct 8, 2016 #3
    Consider conservation of momentum. If the Earth dragged the aether, the aether would also produce a drag on the Earth. The planet would lose orbital energy and spiral into the Sun. If aether drag existed, you wouldn't be here to see it.
  5. Oct 8, 2016 #4
    For the dragging mechanism I'll just assume that gravity helps the ether stick to the planet and neglect effects of rotation which might cause the ether to be in motion wrt earth. Also the only condition for ether is the constancy of speed of light. My doubt arises when trying to understand how stellar abberation falsifies the existence of ether. The author mentions that stellar abberation wouldn't exist at all if earth had a layer of ether in rest wrt it. So I wondered is that really necessary ? Because abberation is nothing but stars moving in circles and even if you had ether you would still see stars moving in circles due to the earth going around the sun. I don't see why this obvious phenomenon would contradict the ether hypothesis.
  6. Oct 8, 2016 #5
    I don't require proof to convince me ether is unnecessary. What I need is a picture of how ether would affect our observations of stellar abberation.
  7. Oct 8, 2016 #6
    There were several different ether models which had different expected results. Wikipedia has some animations showing these effects and outlines the problems found with each model: https://en.wikipedia.org/wiki/Aberration_of_light#Aether_drag_models
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