Bo Posted April 21, 2005 Report Share Posted April 21, 2005 Yes, the endpoints will move faster then the speed of light etc,The problem is simply that a complete rigid object violates the principle of relativity. The reason was given more or less by Q: the atoms have to interact with each other to 'propogate' any movement of the rod. This interaction has a finite speed (namely the speed of light) Bo Quote Link to comment Share on other sites More sharing options...
Qfwfq Posted April 21, 2005 Report Share Posted April 21, 2005 No problem Maddog. Cheers Buffy. :) I'm not talking about sending it as a wave, simply moving the object and seeing if the other end moves at the same time or at least ftl.Whether you ask for one or the other, you'll get the first. Perhaps a material rigid enough at a molecular level could be created.Not without a perfect field, an instantaneous one. The crucial point is that: Having a perfectly rigid pole implies the same as: Having fields that propagate instantly If either one of these two can exist, so can the other. It would give me hope for that jackpot, now standing at €67,000,000 :) Quote Link to comment Share on other sites More sharing options...
ldsoftwaresteve Posted October 12, 2005 Report Share Posted October 12, 2005 But what if light is a particle always and not a wave, ever?We're assuming properties of a wave, are we not?I keep coming back to the probably very stupid observation that light travels really, really fast and we just say, well, that's how fast it travels.Why does light travel at the speed it does?And why does it speed up again to its 'normal' speed once it exits say, a prism?A wave implies solid material having its shape modified so something about light is very solid and we don't need to create a light year long rod at all. The light from a distant star must be very much like a solid rod in the sense that it's contiguous all the way back to when the light stopped, uh, pushing? Something is getting the light back up to speed upon exit from a prism.I've also heard it discussed that one reason we might not see radio waves containing intelligent communications from 'ET's is that they would communicate using light and that it would be damn near instantaneous. So we're looking in the wrong place for the wrong thing.So perhaps this isn't an esoteric subject.With respect to the total mass of a beam of light, it would be very small even going back a long way so that wouldn't present a problem as far as inertia goes, right? Quote Link to comment Share on other sites More sharing options...
Qfwfq Posted October 13, 2005 Report Share Posted October 13, 2005 But what if light is a particle always and not a wave, ever?How do you explain interference patterns? Actually, "wave" is just a breif concise term to sum up the effects of quantum formalism, in which probabilities, or densities of, are predicted as the modulus square of some quantity having amplitude and phase. This quantity for a particle's position changes with time in a way that amounts to the propagation of a wave. Why does light travel at the speed it does?Because, in the vacuum, it can't help it!!! :) And why does it speed up again to its 'normal' speed once it exits say, a prism?Because it steps on the gas!!! :) Quote Link to comment Share on other sites More sharing options...
ldsoftwaresteve Posted October 13, 2005 Report Share Posted October 13, 2005 How do you explain interference patterns? Actually, "wave" is just a breif concise term to sum up the effects of quantum formalism, in which probabilities, or densities of, are predicted as the modulus square of some quantity having amplitude and phase. This quantity for a particle's position changes with time in a way that amounts to the propagation of a wave. Because, in the vacuum, it can't help it!!! ;) Because it steps on the gas!!! :)Why do I need to? So you accept light as a particle? Hmmm. and lastly, Hmmm. My point, exhausted gondolier, :) is that the fella who asked about the rod one light year in length doesn't imagine using a beam of light to send messages because standard theory doesn't consider light to be that kind of particle. And the 'stepping on the gass' effect might be just the other light particles 'behind' it which push or decompress at exit - which might make it possible to send a message by jiggling the particles on this end and having it quickly show up on the other. It's not like we'd have to move a lot of mass so the 'wave' propagation properties using metal might not apply here. Light might not be affected the same way.Do we really understand why light slows down when passing through glass? And when it speeds up coming out of it, does it do so instantly? Also, if we have a beam of light and it travels for say, 10000 feet and strikes glass, is there any kind of 'bounce' that happens at the origination? Any kind of hint of 'compression' at the source? I suppose if there was, we wouldn't have the kinds of tools necessary to detect it yet. If we were able to detect such a thing, we could time it to see how fast the compression traveled back (assuming it did). Quote Link to comment Share on other sites More sharing options...
Erasmus00 Posted October 13, 2005 Report Share Posted October 13, 2005 Do we really understand why light slows down when passing through glass? And when it speeds up coming out of it, does it do so instantly? When light travels through something, say, glass, it excites electrons in the glass (which absorb the light) then the electrons fall down in energy, and spit out new photons. Each photon always travels at c, its the scattering from the electrons that slows the light down. Also, if we have a beam of light and it travels for say, 10000 feet and strikes glass, is there any kind of 'bounce' that happens at the origination? Any kind of hint of 'compression' at the source? I suppose if there was, we wouldn't have the kinds of tools necessary to detect it yet. If we were able to detect such a thing, we could time it to see how fast the compression traveled back (assuming it did). When light strikes something, a wave is reflected (just as one is transmitted). This wave has to travel all the way back to the source before the source feels anything. -Will Quote Link to comment Share on other sites More sharing options...
Doron Shadmi Posted October 16, 2005 Report Share Posted October 16, 2005 A non-composed object that its size is a one light year long, is like a stretched photon and in this case it moves exactly like a non-stretched (normal) photon, which is the light speed. Quote Link to comment Share on other sites More sharing options...
ldsoftwaresteve Posted October 17, 2005 Report Share Posted October 17, 2005 ERASMUS00:When light strikes something, a wave is reflected (just as one is transmitted). This wave has to travel all the way back to the source before the source feels anything. It depends on what you mean by wave. I turn on a flashlight. do you consider the photons which hit the wall to be the wave or are they particles hitting the wall. consider the following:Let's say I put a machine into space and orient a laser toward the space between two stars and hold it in that position for a whole year. I'd say that the photons are connected contiguously with the first photons emitted a year before. That constitutes a fixed rod which happens to be made of particles traveling at C. Relative to each other, those photons are not in motion. To us they are.If I impart some action on the light beam, is there any evidence to suggest that the photons at the other end will be affected at all? If so, that effect travels faster than light.Would we actually be able to answer that question with current technology? Quote Link to comment Share on other sites More sharing options...
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