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Is Anti-Gravity a myth?

  1. Apr 11, 2010 #1
    Hello i was just curious on whether anti-gravity, theoretically speaking is a poissibility. Through Einstein's models of general relativity he explained that gravity wasn't a force, but a direct result of the geometry of space itself. Therefore making the possibility of anti-gravity highly unlikely, except under extreme conditions that are regarded as unlikely or impossible.

    What i would like to know, is anti-gravity possible?, if so what 'extreme' conditions enable it to oppose gravity.
     
  2. jcsd
  3. Apr 11, 2010 #2
    There is no anti-gravity in our universe.
     
  4. Apr 12, 2010 #3

    tot

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    I really find it hard to believe Gravity is unstoppable.
    It seems every force must propagate over some medium.
    We learned that electromagnetism is and now we know how to contort it.
    Can't we contort gravity?
    but perhaps I don't know enough relativity and I am saying something stupid.
     
  5. Apr 12, 2010 #4

    Nabeshin

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    Sure, here's your antigravity: Put another Earth above you. Ta-Da.

    Seriously though, the non-existence of a "negative gravitational charge" (would be something like negative mass) means gravity is impossible to screen or cancel out.
     
  6. Apr 12, 2010 #5

    tot

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    I thought the conclusion was that we don't have a unified theory that unites gravity, Electromagnetic, and the strong and weak forces.
    All of the equations we have have problems.

    Doesn't this leave room for potentially having control of gravity in the future?
     
  7. Apr 12, 2010 #6

    ZapperZ

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    I would like to remind everyone of our PF Rules against unverified speculation. If you are arguing for something, unless it is based on standard textbook knowledge, you must make valid references to support your claim. Otherwise, we will consider it as a speculative post.

    Zz.
     
  8. Apr 12, 2010 #7
    I find it really interesting that so many people equate knowing a physical law to being able to break or "go around" it. This is never true. We have know Newtons laws for a very long time but we are still haven't found a way around them.
     
  9. Apr 12, 2010 #8

    rcgldr

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  10. Apr 12, 2010 #9

    DaveC426913

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    Gravity is only a "force" in Newtonian physics, which has been superceded by GR.
     
  11. Apr 12, 2010 #10
    "By adding a dimension-mapping the universe in four dimensions instead of three-Einstein showed that gravitational force is due to geometry." astronomer Timothy Ferris.
     
  12. Apr 12, 2010 #11
    AFAIK theoretically speaking is a possibility. See http://en.wikipedia.org/wiki/Exotic_matter" [Broken]
     
    Last edited by a moderator: May 4, 2017
  13. Apr 12, 2010 #12

    DaveC426913

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    Not theoretically, hypothetically.

    Big difference.
     
    Last edited by a moderator: May 4, 2017
  14. Apr 13, 2010 #13
    Of course "anti-gravity" is possible! Balloons, airplanes, helicopters etc. do it all the time.

    By this of course what we mean by "anti-gravity" is that the force of gravity is balanced by another equal and opposite force. This is done all the time. It's simple mechanics and does not defy any known rules.

    Now I take it what you mean is could one annul gravity? Or alternatively create an equal and opposite gravity field that cancels the first one. Obviously that answer is "yes" also. As someone already pointed out, you simply place another earth over your head! Two equal and opposite gravity fields that cancel to zero! These places exist between planets.

    Finally we come to science fiction "speculation". Can we have something that "blocks" gravity? or some "drive" that can lift an object without reaction? The famous "anti-gravity paint" perhaps? Unfortunately, If you want to know if such a thing is "possible" first you'd have to understand exactly what gravity is! Simply saying it's a mathematical warp in four-space really doesn't do it. You'd have to have interactions and ways to get them. So far we know that mass warps 4-space but that is already covered in the overhead earth above. So if you wish to build the "Enterprise" you first are going to need a theory that allows you to understand gravity enough and how it works to manipulate it.
     
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