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Just a Couple of questions

  1. Apr 6, 2005 #1
    Hi to anyone reading this. This is my first thread on this site. I am enthusiastic and very interested in physics. Currently i am trying to understand the universe around me. I have a couple of questions id like to ask and if they could be answered that would be greatly appreciated.
    Personally i believe in and ether thus the questions i have are simple but im lost.

    1.What is the exact reason why/how Einstien's theory of special relativity proves the existance of a true vacuum?

    2. Why is the idea of light slowing down in a solid transparent material such as glass so significant?

    3. Are there any predicted properties of a graviton and where could i read about them?

    and finally this may seem a bit weird but

    4. Has anyone ever conducted the search for an ether using a light beam that travels perpendiuclar to the earth rather that horizontal to it?

    Thanks for reading

    p.s. im still in high school so dont be too harsh on me
  2. jcsd
  3. Apr 15, 2005 #2
    As far as I know it doesn't. Quantum Field Theory shows us that a 'true' vacuum is not possible. Quantum Field Theory is derived with respect to SR.

    It doesn't really slow down. Light always travels at same speed. It's the fact that it's absorbed and reemitted by atoms which seems to slow it down. This is basically what physical optics studies.

    The graviton should be a massless spin-2 particle. Google for graviton. Beware of crack pot sites. If you know QFT, google scholar or http://xxx.lanl.gov is your best bet.

    I won't comment on anything regarding ether theory. It's been dead for many years and to my knowledge hasn't been modified to explain all the phenomena the theory of relativity explains.
    Last edited: Apr 15, 2005
  4. Apr 15, 2005 #3
    thanks for the help.
    and in regards to those crackpot sites they really do throw people like me off!
  5. Apr 15, 2005 #4
    It doesn't prove the existence of a true vacuum, but it does disprove the idea of an 'ether'. This is because a central idea of SR is that motion is always relative, there is no such thing as rest (it is impossible to say who is moving and who isn't, because they are both moving relative to each other). If there were an ether, you could measure motion relative to the absolute either (throwing away the idea that motion is always relative). The way Einstein discovered the relativity of motion involves electromagnetism.
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