Stupid Speed of light question
Discussion
This is probably a stupid question - but...
regarding the speed of light issue...
Why would 'information' (in this case a simple binary bit) not travel faster than the speed of light if it were transmitted via a 10,000,000 mile pole...not on earth...obviously
Or a sequence of interlinking cogs - 10,000,000 miles across....
Would the input information; either a push on the pole, or a turn of the inital cog - not arrive at the destination 'immediatley' i.e. faster than light?
or would compression of the medium cause a wavelength to form within the pole - (what about an uncompressible medium, i.e. a carbon nano-widget pole)?
regarding the speed of light issue...
Why would 'information' (in this case a simple binary bit) not travel faster than the speed of light if it were transmitted via a 10,000,000 mile pole...not on earth...obviously
Or a sequence of interlinking cogs - 10,000,000 miles across....
Would the input information; either a push on the pole, or a turn of the inital cog - not arrive at the destination 'immediatley' i.e. faster than light?
or would compression of the medium cause a wavelength to form within the pole - (what about an uncompressible medium, i.e. a carbon nano-widget pole)?
I think the answer lays in the strong and weak forces which bind together a so called "solid" material.
In simple terms I'd expect that you pushing on the end of the rod, would compress the molecules of the surface closest to your finger. The forces in the material would then then seek to re-establish the standard spacing of molecules, either by resisting your finger or by "moving" away. In the course of moving away it's the next layer of molecules which moves, and this creates a ripple. I guess. This is my guess.
In simple terms I'd expect that you pushing on the end of the rod, would compress the molecules of the surface closest to your finger. The forces in the material would then then seek to re-establish the standard spacing of molecules, either by resisting your finger or by "moving" away. In the course of moving away it's the next layer of molecules which moves, and this creates a ripple. I guess. This is my guess.
oli_quick said:
or would compression of the medium cause a wavelength to form within the pole - (what about an uncompressible medium, i.e. a carbon nano-widget pole)?
There is no such thing as an uncompressible medium so yes the individual atoms that were compressed closer together and then moved further apart would do so at less than the speed of lightoli_quick said:
This is probably a stupid question - but...
regarding the speed of light issue...
Because we would have the situation of the speed of light being slower than the speed of sound.regarding the speed of light issue...
The medium would have to be completely inelastic*/rigid for this to work, which is not possible.
(* Or similar meaning non-squishable.)
Bedazzled said:
TheHeretic said:
Because even compression can only go at the speed of light, (probably less due to friction, heat, and so on).
Compression only travels at the speed of sound... you'd be better off using a light signal!We had a question very similar to this a few weeks ago actually.
Bedazzled said:
Yes, double that if you make it out of diamonds, still rather slow compared to a light beam at 300,000,000 m/s!
Of course, like sound, light can vary the time it takes to get from A to B as well. 
in fact, light can be 'detained' in varying materials slower than the speed of sound. Bedazzled said:
I don't think you can transfer information with entanglement, if you measure one particle it determines the state of the other, but it's random like flipping a coin in both places at once.
Strictly true.Doesn't the Einstein-Podolsky-Rosen effect predict the information is simultaneous in a Schrodinger's dead cat format?
Edited by 1point7bar on Tuesday 3rd July 23:45
problem is you've got you deal with refractive index - speed of light in a medium v = c/n where c is your 3 x 10^8 speed in vacuum and n is refractive index (think it of related to bonding/compressibility etc vacuum has n = 1 'most' real things (we'll skip phase and group velocities for now) we've n>1 so c< 3x 10^8 ms-1
at low frequency say sound waves then your looking at sound wave transmission and then your concerned with elastic constants (compressibility of matter), (right up to THz) at higher frequencies still electromagnetic waves (light) your now concerned with the permittivity and permeability of a medium and for a simple insulator say glass where simple optic phenomena can be observed such as refraction then a 'useful' comparative parameter is the refractive index which is related to the permittivity.
at low frequency say sound waves then your looking at sound wave transmission and then your concerned with elastic constants (compressibility of matter), (right up to THz) at higher frequencies still electromagnetic waves (light) your now concerned with the permittivity and permeability of a medium and for a simple insulator say glass where simple optic phenomena can be observed such as refraction then a 'useful' comparative parameter is the refractive index which is related to the permittivity.
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