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Time Travel

  1. Jul 3, 2009 #1
    No pitchforks please (and lay off the caps with the big 'D' on them too)

    Following staying up until 4am (all good stories start like this), and making small talk with a friend doing a degree in physics, we both decided to harp on about theoretical theories such as string etc, and as hours wound on eventually wound up with time travel.

    I'm looking for all of you to poke holes in everything I'm about to say, and explain whether there is any plausibility to what I'm saying - or if men in white coats are on their way.

    Photons travel at the speed of light, but do not have any mass - however it does have an interial mass which in turn creates a gravitational pull (correct me if I'm wrong). Take for instance if we set up a massive tornado/cone building, and in turn fired concentrated photon's in a downward spiral towards the center, this should in essence create an inertial mass at the peak of this cone.

    Say for instance said photons were accelerated by being shot through a silicon atom/very thin sheet of glass, in theory they should emerge at a faster pace, allowing you to increase the inertial gravity experienced at the center of this field. Now imagine in theory that you had say the size and space of venus to construct this type of center - millions upon millions of concentrated lasers firing photons down this arc to create an intertial gravity strong enough to accelerate a neutral particle down along it - would this particle eventually go beyond the speed of light and allow it to travel back in time?

    To begin with the hole poking in my own theory, my friend's first complaint was that intertial mass does not act like mass, and therefore does not have any gravitational pull - as far as I know, he's incorrect - but I'm assuming someone on here would be smart enough to poke further holes in this theory.

    So er.. I'll leave that with you. Cheers :)
  2. jcsd
  3. Jul 3, 2009 #2


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    Staff Emeritus
    Science Advisor

    Welcome to PF. Note that personal theories aren't permitted here (even in the BTSM forum, which is reserved for professionally research alternatives to the SM), however I don't think you really have a theory, but instead have questions about the mass of photons, for example. I'll give the benefit of the doubt, though if this gets any more speculative, I will have to close the thread.

    Your first port of call should be the Physics FAQ: https://www.physicsforums.com/showthread.php?t=104715. Have a read through the "Do photons have mass?" question, and see if that clarifies things for you.

    I'm moving this to general physics, for the aforementioned reason.
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