# Shooting a bullet while traveling the speed of light **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [April 4, 2007, 3:16am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671 "2007-04-04T03:16:36Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Larry\_Borgia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/larry_borgia/32/156_2.png) [@Larry\_Borgia](https://boards.straightdope.com/u/Larry_Borgia)\ **Post date:** [April 6, 2007, 1:28pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/21 "2007-04-06T13:28:07Z")
[QUOTE=Chronos] The simple reality is that asking a question involving an object with rest mass (like, say, a gun) just plain doesn’t make sense. Such a question no more has an answer than does the question “uioegvh fcyu lawelgy?”. [/QUOTE] Could you explain this, **Chronos**? Pardon my ignorance, but I thought it was theoretically possible for any (rest) massive object to be accelerated to any speed below c, however impossible it would be in practice. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [April 6, 2007, 2:30pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/22 "2007-04-06T14:30:25Z")
[QUOTE=Larry Borgia] Could you explain this, **Chronos**? Pardon my ignorance, but I thought it was theoretically possible for any (rest) massive object to be accelerated to any speed below c, however impossible it would be in practice. [/QUOTE] It can, but the question is “while travelling the speed of light” suggesting that, impossibly, _c_ has been acheived, not merely some 99.9999…% of it. The OP’s observations about the energy composition of gun powder, though, escape me. And I dunno what David’s on about at all. ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [April 6, 2007, 2:54pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/23 "2007-04-06T14:54:13Z")
[QUOTE=David Barclay] This being the case, you have convinced yourself that light is in linear motion. The same exact perception you have of a bus or train in motion. Therefore you conclude or Cecil concludes that the speed of light cannot be exceeded. [/QUOTE] I suspect somebody here has read some, but not enough, on the subject. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 6, 2007, 4:45pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/24 "2007-04-06T16:45:00Z")
[QUOTE=Larry Borgia] However, I can’t resist pointing out that arbitrary doesn’t mean the same thing as abstract. [/QUOTE] Quite so. Nor is a definition the same as a measurement. > [@David Barclay](#): > > In order for light to travel one meter in exactly 1/299,792,458ths of a second requires that all 299,792,458 portions of a second be of the same absolute duration. And of course they are, because the length of a second is a defined quantity, not a measured one. David, you, deep in your heart of hearts, believe that 0.9999~ is not the same thing as 1.0. Don’t you? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 6, 2007, 5:14pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/25 "2007-04-06T17:14:40Z")
I suppose this is outside the 5-minute edit window, right? What I meant to say was > [@](#): > > The simple reality is that asking a question involving an object with rest mass (like, say, a gun) travelling at the speed of light just plain doesn’t make sense. Such a question no more has an answer than does the question “uioegvh fcyu lawelgy?”. It does, of course, make sense to talk about things with rest mass travelling at less than the speed of light. And I’d like to thank **David Barclay** for providing more examples of text which doesn’t make sense, and which doesn’t contain things that accidentally resemble crude insults. ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [April 6, 2007, 5:35pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/26 "2007-04-06T17:35:41Z")
[QUOTE=David Barclay] In order for light to travel one meter in exactly 1/299,792,458ths of a second requires that all 299,792,458 portions of a second be of the same absolute duration. If they are not of the same absolute duration you can hardly say that the measurement is exact. It’s an approximation and nothing more, in relation to a linear concept of time, space and motion. [/quote] So how then do you define “absolute duration”? [Quote=David Barclay] I think that simultaneous might be a bit faster than light speed. [/QUOTE] “Simultaneous” isn’t a speed, so your statement is meaningless irrespective of relativity. In any case, according to relativity simultaneity is meaningless when two events are separated in space; in one frame of reference two events can be simultaneous while in another frame of reference they are not. (Apologies to those that are more familiar with the terminology than I am if I used the wrong terminology - I have a feeling that “frame of reference” might not be the correct term, but I don’t cites handy to check my terminology) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 6, 2007, 7:38pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/27 "2007-04-06T19:38:35Z")
> [@](#): > > (Apologies to those that are more familiar with the terminology than I am if I used the wrong terminology - I have a feeling that “frame of reference” might not be the correct term, but I don’t cites handy to check my terminology) Don’t worry, you got it right. I’d be more inclined to say “reference frame” than “frame of reference”, but they mean the same thing. ---
**Author:** ![human\_extinction](https://avatars.discourse-cdn.com/v4/letter/h/839c29/32.png) [@human\_extinction](https://boards.straightdope.com/u/human_extinction)\ **Post date:** [April 8, 2007, 12:55am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/28 "2007-04-08T00:55:08Z")
[QUOTE=Bryan Ekers] The OP’s observations about the energy composition of gun powder, though, escape me [/QUOTE] Well, it seems that the subject has been changed quite a few times from the one I originally intended to set. I didn’t mean to be cryptic or anything Bryan, but say your traveling at the speed of light with the gun and your going to shoot me (while I’m also going ~3x10^8m/s) because I’m not a member of The Straight Dope. So, we are both traveling at the speed of light, along with the gun…But wait, since we are traveling at the speed of light, we have now become light due to the laws of physics. It is debatable at exactly which time our molecules will turn into “light” (if completely at all), but in layman’s terms, when nearing ~3x10^8m/s we will surely not be ourselves. In calculating the energy required to get us moving at the speed of light, you will find the impossibilities of moving at the speed of such a high energy without becoming a high energy. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 8, 2007, 1:43am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/29 "2007-04-08T01:43:31Z")
No, nothing turns into energy. You simply can’t get anything, not even a single particle, to accelerate to the speed of light, no matter what you do, under any circumstances, even theoretical ones. You will be exactly whatever you started with at all times, no matter what speed you finally achieve. Your molecules will never arrive at the speed of light, so they can’t turn into light, which is an impossibility. Your mass (as measured by an outside observer) will increase as your speed increases, but you, within your own reference frame, will notice no alteration of any kind. As **Chronos** said in the first response, it just doesn’t make any sense to talk about mass moving at the speed of light. You can’t even make a theoretical picture of it. Mass moves at less than the speed of light (i.e. Einstein’s constant, C) at all times in our universe.\* You can describe it gaining speed as much as you want. But never achieving light speed. - You don’t get to talk about tachyons unless you have actually found one. 🙂 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 8, 2007, 2:12am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/30 "2007-04-08T02:12:52Z")
> [@](#): > > It is debatable at exactly which time our molecules will turn into “light” (if completely at all), but in layman’s terms, when nearing ~3x10^8m/s we will surely not be ourselves. Nah, you can near it all you want. Remember, velocity is relative, so we could be going at any speed at all, if you measure it in the appropriate frame. For instance, consider the “Oh-my-God particle” (so named after the first thing the researcher said when he saw the data), an extremely high-energy cosmic ray which hit the Earth in 1991. Its speed relative to the Earth was calculated to have been 0.9999999999999999999999951 times the speed of light. Now turn that around: That also means that, relative to the Oh-my-God particle, _we_ were going at 0.9999999999999999999999951 c. Nor is that the limit: The OMG particle is the fastest piece of matter (as opposed to light) which has ever been observed by humans, but you don’t actually need a piece of matter to anchor a reference frame to. One could just as easily construct a reference frame which is travelling relative to us at 0.999999999999999999999999999999999999999999999999999999999999999 c. In such a frame, we’re the ones travelling at that ludicrous speed, but it affects us not at all. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [April 8, 2007, 3:33am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/31 "2007-04-08T03:33:20Z")
[QUOTE=David Barclay] In order for light to travel one meter in exactly 1/299,792,458ths of a second requires that all 299,792,458 portions of a second be of the same absolute duration. If they are not of the same absolute duration you can hardly say that the measurement is exact. It’s an approximation and nothing more, in relation to a linear concept of time, space and motion. This being the case, you have convinced yourself that light is in linear motion. The same exact perception you have of a bus or train in motion. Therefore you conclude or Cecil concludes that the speed of light cannot be exceeded.. [/QUOTE] Actually, I prefer the [Time Cube](http://timecube.com/): Singularity “education” inflicts a dog brain upon Students - ability to be taught servitude - but an inability to ever think opposite of brainwashing and indoctrination - very unlikely to ever recover to acknowledge Nature’s Harmonic Simultaneous Rotating 4 Corner 24 Hr. Days in 1 Earth Rotation. –Dr. Gene Ray, Cubic and Wise Above God. He really does have a better grasp on how to present pseudoscience in the vernacular of the lunatic fringe. To extend on **Chronos** ’ explanation (if that even needs to be done) imagine it like this; for the stationary observer in an unaccelerated reference frame, the difference between the speed of the spacecraft and that of the bullet speed is less than than the normal speed of the bullet in an inertial reference frame by the reciprical of the the [Lorentz factor](http://en.wikipedia.org/wiki/Lorentz_factor). Note that the shooter on the spacecraft doesn’t observe this; owing to relativistic time dilation (multiplied by the same factor) he sees it travel at normal speed in his frame of reference. But both he and the bullet, from the perspective of our intertial reference frame, are moving in slow motion, so everything works out without having to get anyone’s chronograph out of joint. It’s true that at the end of the journey, when the spacecraft decellerates and is once more at rest with respect to the original frame of reference, that his watch will be short–a result of his having undergone acceleration in a non-inertial frame–but this is nothing to be worried about; he traded time for distance, which is the essential point of Special Relativity; they’re two aspects of the same continuum. I’m failing to make heads or tails of **David Barclay** ’s glurgage without getting a pain in my gulliver, but his essential arguments appears to be that time (seen from any particular perspective) relative to any arbitrary distance is variant, which is absolutely true; however, the speed of light with respect to both time and distance is completely invariant, a fact derived from Maxwell’s Equations which substantially predates the development of Special Relativity. This isn’t some foofy interpretation argued about by a bunch of Germans who have an apparent hatred for felines; it’s a widely tested and verified physical theory which has so far held up to almost 150 years of testing and is used every day in consumer electronics and telecommunications. Oh, and “uioegvh fcyu lawelgy?” This is entirely the wrong forum for that question; that’s clearly a Great Debates topic. Stranger ---
**Author:** ![David\_Barclay](https://avatars.discourse-cdn.com/v4/letter/d/4af34b/32.png) [@David\_Barclay](https://boards.straightdope.com/u/David_Barclay)\ **Post date:** [April 8, 2007, 12:55pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/32 "2007-04-08T12:55:32Z")
The point I am trying to make is that there is a basic flaw in the works, as most assume that all seconds are of an equal duration, which is very handy in many cases, but in attempting to evaluate something as important as the speed of light and its relationship to universe such an assumption creates an illusion which limits our ability to move forward. Of course you can measure the linear speed of light, but you can also measure the linear speed of a bus or the linear speed of a bullet. But is the light in linear motion or is this just part of an illusion we have created? Does the speed of light change over time? Of course it does, which is why it is fixed. No the bullet would not exceed the speed of light, never, but simply asking the question in the first place suggests that the motion of bullets and light can be determined on the basis of the same terms, which I believe to be a fundamental mistake. If light does not have a linear speed and all we are measuring is a time differential, we are setting ourselves up to accept a smoke and mirrors routine as the real deal. Cecil claims the speed of light cannot be exceeded, which could be taken to mean that it would be impossible to get from here to there or for anything to get to there from here faster than light. This is a self limiting assumption based on linear thinking. Instantaneous transformation gets something from here to there faster than traveling from the same here to there at or close to the speed of light. If what Cecil meant was that a physical mass cannot linearly travel faster than light, then I would agree completely. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [April 8, 2007, 1:09pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/33 "2007-04-08T13:09:04Z")
[QUOTE=human\_extinction] we will surely not be ourselves. [/QUOTE] Surely not, since I dont go around shooting people for not being SDMB members. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 8, 2007, 3:15pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/34 "2007-04-08T15:15:02Z")
[QUOTE=David Barclay] Does the speed of light change over time? Of course it does, which is why it is fixed. [/QUOTE] Thank you for one of the greatest statements in all history. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [April 8, 2007, 4:57pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/35 "2007-04-08T16:57:37Z")
[QUOTE=David Barclay] Does the speed of light change over time? Of course it does, which is why it is fixed. [/QUOTE] Great, you just blew the illogic controller on my Electronic Monk. Do you know how hard those things are to get? They’re always on backorder, and besides that every time I send it in for repair the sales guy is always hassling me to upgrade to one of their Monk Plus models. Stranger ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 8, 2007, 9:51pm UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/36 "2007-04-08T21:51:24Z")
Hey, don’t sweat it, man. Go over to eBay/GravityControl and look at the stuff offered for bid there. There’s so much illogic at such great prices that you won’t have to go elsewhere to meet your needs for months! ---
**Author:** ![David\_Barclay](https://avatars.discourse-cdn.com/v4/letter/d/4af34b/32.png) [@David\_Barclay](https://boards.straightdope.com/u/David_Barclay)\ **Post date:** [April 9, 2007, 2:41am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/37 "2007-04-09T02:41:48Z")
So the speed of light is constant in your opinion or have I mistaken the meaning of your comments. The constancy of light speed is or was based on a static condition of universe and to the best of my knowledge there is no static universe. So how would you explain a constant having a static value in terms of a dynamic universe? It does not appear logical or even rational, but maybe you know something I don’t. Light speed maintains a relative relationship, therefore the speed of light is relative to the system of reference, whereby the speed of light is different for all systems. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 9, 2007, 2:53am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/38 "2007-04-09T02:53:30Z")
[QUOTE=David Barclay] It does not appear logical or even rational, but maybe you know something I don’t. [/QUOTE] The problem seems to me to be that you think you know something Einstein didn’t. Poor Albert. The Rodney Dangerfield of physicists. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [April 9, 2007, 2:54am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/39 "2007-04-09T02:54:59Z")
[QUOTE=David Barclay] So the speed of light is constant in your opinion or have I mistaken the meaning of your comments. The constancy of light speed is or was based on a static condition of universe and to the best of my knowledge there is no static universe. So how would you explain a constant having a static value in terms of a dynamic universe? It does not appear logical or even rational, but maybe you know something I don’t. Light speed maintains a relative relationship, therefore the speed of light is relative to the system of reference, whereby the speed of light is different for all systems. [/QUOTE] You are throwing around terms without any formal or explicit definition. What, for instance, is a “static universe” versus a “dynamic universe”? How do you model the mechanics of it mathematically in a way that is consistant with physical observations? How can you demonstrate this supposed “relative relationship” of light to a frame of reference, and how do you satisfy (among other notable confirmations of Special Relativity) the apparent invariance of the Michelson-Morley experiment? What say you about Maxwell’s laws–which allow us to predict and account for the behavior of electromagnetic fields–which establish the invariance of light. Don’t tell us about your theory with a bunch of semantically null English doublespeak; show us with mathematics. Stranger ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 9, 2007, 4:38am UTC](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671/40 "2007-04-09T04:38:52Z")
> [@](#): > > This isn’t some foofy interpretation argued about by a bunch of Germans who have an apparent hatred for felines;… Well, they have a sort of love/hate relationship with felines. [Previous page](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671.md?page=1) [Next page](https://boards.straightdope.com/t/shooting-a-bullet-while-traveling-the-speed-of-light/398671.md?page=3)