Speed of Light Constant

[pgrmdave]

How is the speed of light able to remain constant independant of the motion of the observer?

[Tim_Lou]

its a very complicated general relativity questions.

 

moving objects experience time dilation relatively to other frames...

also length contraction.

 

i suggest you to search some info on google....

 

and a constant C does not come from theory, it comes from observation, its just the way nature is....

 

and GR is based on this constant C.

[gpdone]

How is the speed of light able to remain constant independant of the motion of the observer?

 

If my question below seems not to be related to what you are trying to say please clarify.

 

You seem to be implying that the motion of an observer should have some effect on the constant C. This would mean that you would assume that a machine set to fire one ping pong ball per second at you, and was in fact doing so, that if you run towards it you would believe that the rate of fire has actually increased instead of only feeling like it has increased.

??

 

Lee

[TINNY]

how does length contraction play its role in keeping the C constant?

[pgrmdave]

If my question below seems not to be related to what you are trying to say please clarify.

 

You seem to be implying that the motion of an observer should have some effect on the constant C. This would mean that you would assume that a machine set to fire one ping pong ball per second at you, and was in fact doing so, that if you run towards it you would believe that the rate of fire has actually increased instead of only feeling like it has increased.

??

 

Lee

 

It is exactly like that, actually. The ping pong balls would be moving faster relative to a body moving towards them than away from them. The rate of fire has nothing to do with it, at least, I don't think it does.

[gpdone]

It is exactly like that, actually. The ping pong balls would be moving faster relative to a body moving towards them than away from them. The rate of fire has nothing to do with it, at least, I don't think it does.

 

How about this one then...you are running north on Main St at 25 MPH and you run head on into a car going 5 MPH...Irrespective of the 30 MPH amount of damage to your body, how fast was the car moving? How is it that a car moving only 5 MPH can do 30 MPH damage to a human?

 

Lee

[pgrmdave]

But that example makes logical sense, the car was moving 30 MPH relative to the person hit, what wouldn't make sense would be if it had only done 5 MPH damage. Assume that the car represents light, your example is what makes sense to me, one can change it's speed relative to themselves by motion towards or away, but light does not change it's speed. The car would only have hit me at 5 MPH.

[gpdone]

Well sort of....You would be correct to believe that the rate of the ping pong machine would not have really changed either, though GR would like you to believe it and use their formula to 'prove' that' a mathmatical possibility is also possible in the real world. This is what length contraction and time dilation are..ways of explaining mathmatical soultions to a real world dilema but at its best for real world applications it is only an illusion which serves to satisfy our need to understand while we figure out how the same results arrise actually. Optical effects account for most GR proofs and other possiblities are still open to explain degrading rotation of some Pulsars. Our own Sun could give us a strong clue soon! So NOW YOU KNOW..I R a Crack pot too! One who believes in the tooth fairy and 'only' three spacial dimentions.

 

Lee

[Tim_Lou]

the thing is, experiements show that C is always constant regardless of whatever frame it is,

thats just experiment data, and theories must be made to explain...

 

if C wasnt constant, then considering that the earth is moving relatively to the sun, and relativity to the galaxy.. the C would be all messed up. In one direction, it might be .5C, in other direction, it might be 2C, then there would be great disgreement on scientific experiements...

 

also, if C wasnt constant, then there must be an absolutely frame with zero velocity which measures the right C, it was assumed that this thing (ether) existed, but.... no one had ever found it.

[Tim_Lou]

for TINNY's question... well i dont know much..

 

considering someone measuring the length of an object, he msut mark the both ends of the object at the same time.

 

but time isnt the same to frames that move relatively to each, therefore, the "marks" they make do not aggree with each other, thus measurments in both frames do not agree with each other... but they apply the proper measuring method, so both must be right.....

 

(i dont know if it makes sense or not... i dont fully understand it either, well...)

 

we cant say whatever's roles on keeping C constant,

in fact, these assumptions are based on the constant C.

[geko]

This thread has confused me (i must admit i dont really get the constant C thing either) but

 

Originally Posted by pgrmdave

How is the speed of light able to remain constant independant of the motion of the observer?

 

Originally posted by gpdone

You seem to be implying that the motion of an observer should have some effect on the constant C. This would mean that you would assume that a machine set to fire one ping pong ball per second at you, and was in fact doing so, that if you run towards it you would believe that the rate of fire has actually increased instead of only feeling like it has increased.

??

 

 

I seem to think that you're talking about the wrong object.

 

i.e. motion of observer = effect on constant C; an analogy of this = believing machine firing ball increases rate of fire (i.e. believing the light source is sending light at greater velocity). But this isnt so because it's the rate of the ball (light) that changes, not the machine (source) firing quicker.

 

eg. machine fires ball at 25k, the 'instant' it fires you achieve 25k parallel to it. This would mean the ball would apear stationary to the observer and the background would be moving? Likewise, a vent is opened to let a ray of light out, the 'instant' the first particle ejects from the vent you achieve 375000kms (<-speed of light?) in the same direction. This would mean the particle of light that you're travelling alongside would appear stationary?

 

My thinking is wrong to known laws i think, but i just dont get that if you were travelling 375000kms light would still travel 375000kms away from you - this would equal a speed of 750000kms for the said particle of light, no? Could someone come back to the thread and hold my hand whilst they guide me through it please?

 

i have read physics books and stuff but have just never accepted (or maybe understood) the constant of C

[pgrmdave]

 

My thinking is wrong to known laws i think, but i just dont get that if you were travelling 375000kms light would still travel 375000kms away from you - this would equal a speed of 750000kms for the said particle of light, no? Could someone come back to the thread and hold my hand whilst they guide me through it please?

 

 

Well, I'm where you are. Obviously experimental data cannot lie, but logic dictates that something is wrong, addition of velocities does not occur like it should. Consider this, assume the maximum speed of the universe ( C ) was within human experiance, say, 60 m.p.h. Within old laws of addition of velocities, if you were on a train moving 50 m.p.h. and you ran towards the front at 20 m.p.h., you would acheive a velocity, relative to an outside observer, of 70 m.p.h., greater than C, but that isn't true, the maximum velocity would still be only 60 m.p.h.

[Tormod]

I don't have any top-of-my-head good answers for you guys, but here is at least a secion of a Wikipedia article on the invariance of the speed of light:

 

http://en.wikipedia.org/wiki/Speed_of_light#Constant_in_all_reference_frames

[ImZ]

Well, I'm where you are. Obviously experimental data cannot lie, but logic dictates that something is wrong, addition of velocities does not occur like it should. Consider this, assume the maximum speed of the universe ( C ) was within human experiance, say, 60 m.p.h. Within old laws of addition of velocities, if you were on a train moving 50 m.p.h. and you ran towards the front at 20 m.p.h., you would acheive a velocity, relative to an outside observer, of 70 m.p.h., greater than C, but that isn't true, the maximum velocity would still be only 60 m.p.h.

 

I try to expalin my theory in English but I don`t know if you guys will understand it.

You said that if the maximum speed of the universe ( C ) was within human experiance, say, 60 m.p.h. and if you were on a train and ran towards the front at 20 m.p.h., you would acheive a velocity, relative to an outside observer, of 70 m.p.h., greater than C. This isn`t possible because if the maximum speed of universe ( C ) was 60 m.p.h then anything can`t move faster than it. It so because the maximum speed of universe is bound up with mass (n+1=infinity) so if the train was moving 50 m.p.h then maximum speed you could achieve would be 60 m.p.h because if anyone would want to increase this velocity than it would exert strength which would be same as the mass (n+1) only then something or someone could

move faster than the speed of universal ( C ). But it isn`t possible because there`s no way you can find this kind of power. Hope you guys will understand what I`m talking about. And

 

I`m really happy that I joined with this great forum. I looked around and I found some really interesting stuff. This really is the best forum I`ve found....respect :)

[Tormod]

I`m really happy that I joined with this great forum. I looked around and I found some really interesting stuff. This really is the best forum I`ve found....respect :)

Thank you. You are very welcome here!

[hefner]

How about this one then...you are running north on Main St at 25 MPH and you run head on into a car going 5 MPH...Irrespective of the 30 MPH amount of damage to your body...

No. According to Einstein (ie. his Relativity premise), your body would sustain only 29.99999999999 MPH worth of damage to it. Lightspeed will be assessed the same by all observers regardless of their supposed motions. Light always behaves, per the reckoning of each observer (man or machine), as if that observer's native 3D coordinate system is THE master medium for electromagnetic wave propagation. And yes, by "native" is meant: that x-y-z frame relative to which the observer is stock still in space. C is assessed uniformly by all observers... so it's time and space and synchronicity that must give way and become ambiguous.

[maddog]

I have found some of this thread humorous. Yet not so accurate.

 

Einstein created the Special Theory of Relativity that deviated from Galelian Relativity in

that for something with mass would experience a time dilation (though not from his point of

view, it would be from another observer in a different reference frame). What was odd was

his notion that light itself would not experience any effect in any frame whatsoever.

 

This has since been corroberated many times. A good example is muon decay. Cosmic Rays

hit the earth at a prolific rate. When one hits say an Oxygen molecule in the upper atmosphere,

this can create a transmutation creating a muon that hit the earth. However, were a muon

not in motion, its half life is only a few microseconds. Because of its very fast motion (speed),

it can actually hit the ground (~ 600 seconds).

 

Now as for the earlier example of how someone in a car at 5 mph hitting a car at 30 mph,

it is simply the brain hitting the skull of the person moving at 5 mph with the transfer of

momentum from the mass of the car moving at 30 mph. Yes, a killing blow.

 

Maddog