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man from kibish
2008-Sep-28, 07:05 PM
My question is related to the speed of light c.
How can the scientific community be certain that light is not accelerating/decelerating by a very very small miniscule factor that is not noticeable at 'close' range [thus we think 'c' has a finite speed] and becoming noticeable only as one drifts further and further away from Earth? Inflating universe prompt me to ask this question.

The nature of electromagnetic propagation [changing electric field bringing about a changing magnetic field etc etc] seems to imply a 'kicking' effect and kick after kick after kick brings about a higher and higher speed.

Has any research been done about this - accelerating electromagnetic radiation - ?
Where can I find it?

Thanking you [plural] beforehand for your replies.

yours truly,
Stephen your Man from Kibish

cjameshuff
2008-Sep-28, 09:27 PM
My question is related to the speed of light c.
How can the scientific community be certain that light is not accelerating/decelerating by a very very small miniscule factor that is not noticeable at 'close' range [thus we think 'c' has a finite speed] and becoming noticeable only as one drifts further and further away from Earth? Inflating universe prompt me to ask this question.

What reason is there to think it might accelerate?

There's been many, many measurements of the speed of light, and in vacuum, it is always measured to be the same thing. The measured speed is consistent even dealing with probes moving out of the solar system and watching reflections of stellar outbursts against clouds of dust and gas. The equations describing electromagnetic forces have been used to construct incredibly precise systems that depend extremely strongly on the speed of light, and those equations predict a constant speed.



The nature of electromagnetic propagation [changing electric field bringing about a changing magnetic field etc etc] seems to imply a 'kicking' effect and kick after kick after kick brings about a higher and higher speed.

The energy balances out, and neither increases or decreases over time without an outside cause. You're trying to apply a familiar analogy to a situation where it really doesn't apply.

greatgreekcollector
2008-Sep-29, 02:12 AM
Hi Stephen,

The truth is that most simple replies are based on simple Earth measurements, and closed thought processes.

And yes the speed of light is NOT CONSTANT, and its speed is dependent on distance traveled, which we know will change with time which will also change when it traverses the "know universe" and will be stopped when it goes into black holes (& other objects), and start up again everytime there is a new Big bang from that particular black hole's time to go Big Bang. And a new cycle begins before we are any the wiser, while the rest of the universe is still going through its own "bang to black hole" cycles.

Time and distance are variable and specifically are generally relevant to that part of the "cycle" that is presumed to be stable. And we know that the "cycle" has expansion and contraction and a start and a finish, so there can specifically be answered that light speed is a variable factor in its own life cycle.

Lepton
2008-Sep-29, 02:18 AM
SNIP
Can you please keep this ATM stuff in the ATM forum so this can remain an educational resource.

spratleyj
2008-Sep-29, 02:29 AM
Yep, that really doesn't belong here... And to answer the question all experiments have shown c to be a constant, plus it works nicely into relativity, and there is not "theoretical" reason to think otherwise, so that's why c is viewed as a natural constant.

Drunk Vegan
2008-Sep-29, 02:37 AM
I liked Vernor Vinge's work where there were "slow zones" in the galaxy and Earth happened to be in one of them.

In other areas it was possible to go much faster than the speed of light.

Sheer fantasy, but fun.

cjameshuff
2008-Sep-29, 03:44 AM
I liked Vernor Vinge's work where there were "slow zones" in the galaxy and Earth happened to be in one of them.

In other areas it was possible to go much faster than the speed of light.

I got the impression that the speed of light still held, but there was something more subtle along the lines of quantum effects being more predictable outside of the slow zone, allowing higher technology (like artificial gravity and FTL drives) to function.

And yeah, sheer fantasy...but a fun concept and interesting books. The Tines were a particularly interesting group of people...

astromark
2008-Sep-29, 06:13 AM
The only room for speculative accelerating velocities of light might simply be a miss-understanding of the expansion of the universe and the effect that would have on the path and velocity of light. Yes light only travels at C. always. But if the space it is traveling through can be proved to be expanding then it might be possible to contradict this light speed velocity rule.

man from kibish
2008-Sep-29, 07:12 AM
What reason is there to think it might accelerate?


Hi cjameshaff,
The fact that unlike a projectile leaving a cannon, electromagnetic radiation is self propeling.

Has any research been done about this speed/acceleration? Where can I read about it?

Please responders keep this purely educational.

regards, Stephen

man from kibish
2008-Sep-29, 07:18 AM
Yep, that really doesn't belong here... And to answer the question all experiments have shown c to be a constant, plus it works nicely into relativity, and there is not "theoretical" reason to think otherwise, so that's why c is viewed as a natural constant.


It belongs here because the question is seeking researched work on the subject.

To answer your answer I have looked up the internet to learn how the speed of light has been measured throughout the years and none of the experiments seems to have been designed to measure acceleration so the outcome was merely a search for an exact value of the speed c.

yt, Stephen

sirius0
2008-Sep-29, 12:02 PM
It belongs here because the question is seeking researched work on the subject.



I got the impression that spratleyj was reffering to the greatgreekcollector's comments, not your question. Hmm can't change the bold.

Personally don't like your kick kick, but if I was to use it I would say that the oscillation is neither under damped or over damped due to a relationship between the permeability and permittivity of space coming out as a constant. Therefore a photon is a soliton (http://en.wikipedia.org/wiki/Soliton) in this sense, but is really pushing the analogy. The fact is that light approaching us from any distance cosmollogically is not getting faster on route. (just can't get this bold off, I am not yelling honest :))

cjameshuff
2008-Sep-29, 01:11 PM
The fact that unlike a projectile leaving a cannon, electromagnetic radiation is self propeling.

Self propagating. Electric and magnetic fields, each continually transferring its energy into the other, but at a certain displacement in space. You could use a similar argument to say that sound should accelerate...there's always a high pressure area in a sound wave pushing forward, after all.



Has any research been done about this speed/acceleration? Where can I read about it?

There have been many experiments to measure the speed, and other experiments that depend on knowing it to extremely high accuracy. The inconsistent results from accelerating light would have been noticed. Things to look for...speed of light measurement, radar, interferometry, GPS, lasers and other EM resonant devices...

And what about the nature of "accelerated" light? It would have gained energy from nowhere, and its wavelength would be out of step with its energy, and it would violate causality. You could send signals back in time by occluding and exposing distant galaxies. And why is light always created at a fixed initial velocity? Why couldn't you constrain the wavelength somehow, squeeze in a bit more energy, and get light that acts as if it had been accelerating for millions of light years?

loglo
2008-Sep-29, 01:16 PM
It belongs here because the question is seeking researched work on the subject.

To answer your answer I have looked up the internet to learn how the speed of light has been measured throughout the years and none of the experiments seems to have been designed to measure acceleration so the outcome was merely a search for an exact value of the speed c.

yt, Stephen

When you repeatedly measure the speed of light to be the same speed then that is a null result on testing for positive acceleration.

a1call
2008-Sep-29, 01:29 PM
... plus it works nicely into relativity...

That deserves more than a passive mention.

Constancy of speed of light in vacuum is an aspect of relativity and time dilation. It is reported that experiments have confirmed time dilation within expected values (no acceleration). These experiments by their nature are extended in time which should point out any deviation in the speed if any.

Constancy of speed of light in vacuum is one of the fundamental aspects of nature and there is no escaping it, same way there is no escaping the law of preservation of matter and energy. They are all interrelated and some very bright minds have put forward theories which attempt to describe them.

man from kibish
2008-Sep-29, 03:27 PM
[QUOTE=a1call;1333364]That deserves more than a passive mention.

Constancy of speed of light in vacuum is an aspect of relativity and time dilation. It is reported that experiments have confirmed time dilation within expected values (no acceleration). These experiments by their nature are extended in time which should point out any deviation in the speed if any.

I left it out completely since postulate 2 of relativity is that
"Light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body". So for relativity c cannot be otherwise.

man from kibish
2008-Sep-29, 03:50 PM
There have been many experiments to measure the speed, and other experiments that depend on knowing it to extremely high accuracy. The inconsistent results from accelerating light would have been noticed. Things to look for...speed of light measurement, radar, interferometry, GPS, lasers and other EM resonant devices...


Cjameshuff,
The experiments to measure the speed of light I have come across are all 'local', measured at relatively small distances. Can one measure the speed of light coming from the deep universe? How?

quote:
[And what about the nature of "accelerated" light? It would have gained energy from nowhere, and its wavelength would be out of step with its energy, and it would violate causality]. unquote

Kindly explain some more about this out of step wavelength [what it implies] and what may be observed to show it.

thanks, Stephen your Man from Kibish

man from kibish
2008-Sep-29, 04:05 PM
When you repeatedly measure the speed of light to be the same speed then that is a null result on testing for positive acceleration.

Can you name one experiment that nulls the notion of positive acceleration? That would clear up the issue once and for all.

yt, Stephen

Lepton
2008-Sep-29, 04:07 PM
Can you name one experiment that nulls the notion of positive acceleration? That would clear up the issue once and for all.

yt, Stephen

Are you promoting a theory or are you asking a mainstream question?

cjameshuff
2008-Sep-29, 05:02 PM
The experiments to measure the speed of light I have come across are all 'local', measured at relatively small distances. Can one measure the speed of light coming from the deep universe? How?

Occlusion of distant bodies has been used to test for varying speeds of light. The silhouette of a planet would appear at different places depending on how fast the various components of the background light are moving, blurring them and leading to things like the image of a distant galaxy being superimposed over the image of a planet or moon. This is not observed.



Kindly explain some more about this out of step wavelength [what it implies] and what may be observed to show it.

The acceleration would produce photons with energy in excess of what would be expected from their wavelength. If this were possible, I'd also expect a spectrum of energies from locally produced monochromatic (single wavelength) light, and differences in the output of sources that produce light in different ways.

man from kibish
2008-Sep-30, 04:49 PM
Are you promoting a theory or are you asking a mainstream question?

I am doing the latter and at the same time challenging replies for scientific evidence. I am simply curious to learn how science came to the conclusion that c is not an acceleration, hence my original question at the very top.

Cjameshuff has now given me some interesting leads to check. Thank you.

Stephen

John Mendenhall
2008-Sep-30, 07:18 PM
I am doing the latter and at the same time challenging replies for scientific evidence.

If you want to challenge the mainstream, it's ATM. You've gotten answers from some very good and very patient people - more patient and more knowledgeable than me. If you want to promote an ATM idea, you should move to ATM.

man from kibish
2008-Sep-30, 07:35 PM
If you want to challenge the mainstream, it's ATM. You've gotten answers from some very good and very patient people - more patient and more knowledgeable than me. If you want to promote an ATM idea, you should move to ATM.

I am not challenging mainstream John, my challenge was for those 'answers' that did not answer my original question [see top of the thread - Has any research been done about this - accelerating electromagnetic radiation - ? Where can I find it?].

It is my want for the 'how' of what they know is the truth.

I find cjameshuff's replies helpful and therefore thank you cjameshuff.

end
Stephen

a1call
2008-Sep-30, 11:23 PM
An accelerating light's speed would imply that star-light would:

*- Be faster the further away a star is and thus not equal
*- Be faster than the light emanating from a candle across the room

Both of these notions are very obviously false and easily verifiable.

Why would you even consider the possibility?

man from kibish
2008-Oct-01, 07:18 PM
An accelerating light's speed would imply that star-light would:

*- Be faster the further away a star is and thus not equal
*- Be faster than the light emanating from a candle across the room

Both of these notions are very obviously false and easily verifiable.

Why would you even consider the possibility?

I considered the possibility mainly because I think that :
1] a self propagating mechanism has a very very low probability [statistically speaking] of having a fixed speed. Almost inconcievable...

When I searched for experiments that measure the speed of light I noted that it not possible to measure the speed of light of the light coming from the stars. Only local measurements are possible [local here implies that 'start and end of measurement are not far apart cosmologically speaking].

Hence if there was a very very small acceleration it would not be noted 'locally'.

Easily verifiable only if the acceleration is significant - see my original post.

regards, Stephen your friendly man from Kibish
[actually an EU citizen with a special interest in the antiquity of Man]

man from kibish
2008-Oct-01, 07:33 PM
An accelerating light's speed would imply that star-light would:

*- Be faster the further away a star is and thus not equal

Why would you even consider the possibility?

A1Call,
Another reason I asked is that when I considered the implications I thought that a galaxy at the edge of the universe might look brighter to us than it actually is in practice... and suddenly Quasars came to mind.

Ok, you can smile now!

sahhiet, Stephen

nauthiz
2008-Oct-01, 07:58 PM
When I searched for experiments that measure the speed of light I noted that it not possible to measure the speed of light of the light coming from the stars.
I think it is:

Set up an experiment with two stations: one to block light coming from a star, one to detect it. By blocking and unblocking the light's path, you're effectively turning the star on and off, and can therefore measure the amount of time it takes for light to propagate from the screen's location to the detector.

(The basic idea I'm thinking of is to adapt the Fizeau experiment to use a celestial object as the light source.)

Grey
2008-Oct-01, 08:28 PM
When I searched for experiments that measure the speed of light I noted that it not possible to measure the speed of light of the light coming from the stars. Only local measurements are possible [local here implies that 'start and end of measurement are not far apart cosmologically speaking].Except that this isn't true. One of the earliest methods of measuring the speed of light was from the aberration of starlight (http://en.wikipedia.org/wiki/Aberration_of_light). This effect depends on the ratio of the transverse speed of the Earth as it revolves and the velocity of the incoming light. It makes objects appear in a slightly different position in the sky, and since the Earth conveniently shifts its direction every six months, the apparent position changes as well. James Bradley used this effect in 1728 to calculate the speed of light. This effect is observed to be completely unaffected by the distance to the object we're viewing. If light accelerated as it travelled (and so light from objects at different distances had different speeds), the position difference would not be the same. In that case, we'd see distant things like galaxies moving relative to the (much, much closer) foreground stars in an annual pattern. No effect like that has been observed, hence, light coming from all objects in the sky must have the same speed, regardless of how far it has travelled.

stutefish
2008-Oct-01, 09:01 PM
I considered the possibility mainly because I think that :
1] a self propagating mechanism has a very very low probability [statistically speaking] of having a fixed speed. Almost inconcievable...

When I searched for experiments that measure the speed of light I noted that it not possible to measure the speed of light of the light coming from the stars. Only local measurements are possible [local here implies that 'start and end of measurement are not far apart cosmologically speaking].

Hence if there was a very very small acceleration it would not be noted 'locally'.

Easily verifiable only if the acceleration is significant - see my original post.

regards, Stephen your friendly man from Kibish
[actually an EU citizen with a special interest in the antiquity of Man]
Even if it were a very small acceleration it would still accelerate a lot over the several billion light-years necessary to reach our "local" space. We'd still notice that as it arrived at Earth, it was travelling a lot faster than light that had only started traveling a millisecond ago, when we turned on a lightbulb on the other side of the room.

A car that starts accelerating very slowly, from three miles away, will still be going faster than a car that starts accelerating very slowly, from three feet away, even if we measure both of them when they are only three feet away.

cjameshuff
2008-Oct-01, 09:02 PM
I considered the possibility mainly because I think that :
1] a self propagating mechanism has a very very low probability [statistically speaking] of having a fixed speed. Almost inconcievable...

It is almost inconceivable for it to be anything else. Nothing else is observed to speed up without end and without external energy input. Sound waves propagate at a constant speed, waves in water do so, a compression pulse in a long spring does so...it's just a flaw in your conception. The numbers balance out exactly, and additional complexity would be required to describe accelerating light with just one possible initial velocity, which does not vary depending on wavelength. I doubt whether such a thing could be made logically consistent, and it would conflict with observations of occlusions of distant objects.



When I searched for experiments that measure the speed of light I noted that it not possible to measure the speed of light of the light coming from the stars. Only local measurements are possible [local here implies that 'start and end of measurement are not far apart cosmologically speaking].

As mentioned, such experiments are possible and have been done. In early theories of light, it was uncertain whether the speed of light depended on the speed and distance of the emitting object, and so a great deal of effort was spent on measuring the speed of light using stars and galaxies.

If light accelerated, we would see a distant galaxy become hidden before we saw the image of a planet cover that portion of the sky. We would then see the galaxy appear superimposed on the other side of the planet, its light having raced ahead of that reflected off the planet while traveling the several dozen (or more) light minutes to Earth, before the planet moved away. The silhouette would in general be "fuzzy", stars and galaxies in the background disappearing and reappearing at different times depending on their distance. A sufficiently distant object would blink out and reappear before the image of the planet even reached it, the images then overlapping as they pass each other.

Occultations are observed to measure the speed of light, to look for gravity lensing, to measure asymmetries in the lensing to measure the speed of gravity, and to get spectroscopic readings of atmospheres, among other things. This would certainly have been observed, if light accelerated with distance.

cjameshuff
2008-Oct-02, 01:45 PM
It is almost inconceivable for it to be anything else. Nothing else is observed to speed up without end and without external energy input. Sound waves propagate at a constant speed, waves in water do so, a compression pulse in a long spring does so...it's just a flaw in your conception.

Rather than two things alternating in giving each other pushes, think of a sphere rolling on a flat plane. A given atom on the surface, starting out at the bottom, must accelerate forward and upward until it is moving forward and upward at the speed of the whole. It then starts decelerating in the upward direction while continuing to accelerate forward until its upward motion halts and it reaches the top of the sphere, moving forward twice as fast as the sphere as a whole. It then starts decelerating in the forward direction and accelerating downward until it reaches the front, and then decelerating downward and backward until it is at rest relative to the plane. All parts of the sphere are continually accelerating, yet the ball never changes speed without some outside influence.

A rolling sphere is an extremely weak analogy for a photon, but it shows why this sort of thing does not result in an increase or decrease of speed.

papageno
2008-Oct-02, 05:03 PM
What reason is there to think it might accelerate?

Hi cjameshaff,
The fact that unlike a projectile leaving a cannon, electromagnetic radiation is self propeling.

Then why aren't we observing accelerating sound waves or water waves?