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Thread: Possibly idiotic question about relativity

  1. #1 Possibly idiotic question about relativity 
    Forum Freshman War Arrow's Avatar
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    I understand why time experienced by someone travelling close to the speed of light runs slow (in relative terms) due to the increase of mass (?) however, I am having trouble finding an answer to the following question.

    Imagine a hypothetical means by which a person can travel (near instantaneously) from point A to point C without crossing point B (the intervening distance) - whether "wormhole" or "space warp", the method of travel does not matter in this instance. Anyway, if points A and C are one light year apart, then the journey is surely analogous to FTL (which is as we know impossible). My question is this: Given that this hypothetical journey involves no object literally travelling at any particular velocity, and thus not accumulating additional mass, would time (as experienced by this traveller) run at the same rate relative to that of a non-traveller (irrespective of what happens to the light) or would some dilation (in theory) occur? Would the journey be truly instantaneous or would the person arrive at point C some great length of time before or after departure from point A (keeping in mind the fictitious nature of this form of travel).

    Apologies for what may be an awkward (and first!) question (as in poorly expressed), or what I realise may not even be a legitimate question. Any advice or pointers would be greatly appreciated. I'm actually a (fiction) writer so this is research for something I'm working on. I think it's important (for the purposes of the question) to ignore the impossibility of FTL travel or indeed my suggested equivalent-without-physical motion alternative to FTL travel. I suppose the core elements of my question are:

    1) Increased mass (leaving aside violation of causality as an"after effect") prevents FTL travel, yes? Where does this mass derive from, or rather which part of the travel (I'm assuming it's the velocity) leads to the increase of mass?

    2) If (hypothetically speaking) one could travel close to the speed of light without an increase in mass, would FTL then be (in theory) possible (once again suspending disbelief where causality is concerned)?

    Ugh. Think I need to sit down...

    PS. If any mod thinks there might be a more appropriate section for this question, please feel free to move it. I'm new here so I'm bound to bump into a few things at first.


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  3. #2  
    Forum Radioactive Isotope MagiMaster's Avatar
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    You only experience dilations based on how fast you pass through space. If you warp space, you can cover more un-warped distance using less space, so less dilation, if that made sense.


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  4. #3  
    Forum Freshman War Arrow's Avatar
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    Thanks, that makes perfect sense and is as I thought.

    For what it's worth (and I can feel this moving to the pseudoscience area along with all the other FTL threads even as I write) this question was inspired by firstly, using a sequential (but otherwise static) jump method of travel as a means of crossing huge distances without time dilation as a literary device in various science-fiction shorts I've been working on.. and reading Stephen Baxter's Exultant (fantastic novel) which features an FTL drive which actually takes the pilot back in time. Alarm bells rang at this instant because it suggested, what with Stephen Baxter being who he is, that I'd screwed up my own literary device in relation to relativity.

    But maybe not, I guess.
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  5. #4  
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    Quote Originally Posted by War Arrow
    Thanks, that makes perfect sense and is as I thought.

    For what it's worth (and I can feel this moving to the pseudoscience area along with all the other FTL threads even as I write) this question was inspired by firstly, using a sequential (but otherwise static) jump method of travel as a means of crossing huge distances without time dilation as a literary device in various science-fiction shorts I've been working on.. and reading Stephen Baxter's Exultant (fantastic novel) which features an FTL drive which actually takes the pilot back in time. Alarm bells rang at this instant because it suggested, what with Stephen Baxter being who he is, that I'd screwed up my own literary device in relation to relativity.

    But maybe not, I guess.
    This time distortion is still only a theory, and I do not buy it at all.

    They did experiments with devices that were not properly shielded against the radiations present, during the experiment. So although they have gotten effects, with electrons, that we could duplicate here on earth standing still.

    These effects that would alter the device, would not alter time here on earth. There is no solid proof or even the slightest proof, that time was effected.

    And all the proof in the world that time is far beyond the simple reactions and interactions of matter.

    Sincerely,


    William McCormick
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  6. #5 Re: Possibly idiotic question about relativity 
    . DrRocket's Avatar
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    Quote Originally Posted by War Arrow
    I understand why time experienced by someone travelling close to the speed of light runs slow (in relative terms) due to the increase of mass (?) however, I am having trouble finding an answer to the following question.

    Imagine a hypothetical means by which a person can travel (near instantaneously) from point A to point C without crossing point B (the intervening distance) - whether "wormhole" or "space warp", the method of travel does not matter in this instance. Anyway, if points A and C are one light year apart, then the journey is surely analogous to FTL (which is as we know impossible). My question is this: Given that this hypothetical journey involves no object literally travelling at any particular velocity, and thus not accumulating additional mass, would time (as experienced by this traveller) run at the same rate relative to that of a non-traveller (irrespective of what happens to the light) or would some dilation (in theory) occur? Would the journey be truly instantaneous or would the person arrive at point C some great length of time before or after departure from point A (keeping in mind the fictitious nature of this form of travel).

    Apologies for what may be an awkward (and first!) question (as in poorly expressed), or what I realise may not even be a legitimate question. Any advice or pointers would be greatly appreciated. I'm actually a (fiction) writer so this is research for something I'm working on. I think it's important (for the purposes of the question) to ignore the impossibility of FTL travel or indeed my suggested equivalent-without-physical motion alternative to FTL travel. I suppose the core elements of my question are:

    1) Increased mass (leaving aside violation of causality as an"after effect") prevents FTL travel, yes? Where does this mass derive from, or rather which part of the travel (I'm assuming it's the velocity) leads to the increase of mass?

    2) If (hypothetically speaking) one could travel close to the speed of light without an increase in mass, would FTL then be (in theory) possible (once again suspending disbelief where causality is concerned)?

    Ugh. Think I need to sit down...

    PS. If any mod thinks there might be a more appropriate section for this question, please feel free to move it. I'm new here so I'm bound to bump into a few things at first.
    The difficult wity your scenario is that it is basically impossible. To hold a wormhole open, if possible at all, has been shown to require two things -- 1) an exotic quantity called negative energy and 2) for a macroscopic wormhole more of it in terms of E=mc^2 than the equivalent of all the mass in the observable universe.
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    Forum Freshman War Arrow's Avatar
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    Thanks, I'm aware of the wormhole problem (pardon the understatement). For the sake of a narrative I'm invoking the (possible) cop out device of "means that are as yet not fully understood" and are thus necessarily described as such, but not "wormholes" - the idea, aside from being impossible as you pointed out, seems overused and likely to date very quickly as a fictional device.

    Anyway, I think my question regarding what role mass may (or may not) play has kind of been answered for the time being.
    "For as long as the world shall endure, the honour and the glory of Mexico-Tenochtitlan must never be forgotten."
    - Chimalpahin Quautlehuanitzin
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