Anyone attempting to argue the Special Theory of Relativity needs to understand the basics of how light travels, and how we perceive it.


Einstein wrote that the speed of light does not depend on the speed of the object emitting the light. To prove this, Einstein referred to De Sitter’s observation of the binary stars, which are two stars that are orbiting each other. De Sitter concluded that if the speed of light were dependant on the speed of the star, then the light emitted from the star as it is traveling towards us would eventually catch up to the light that was emitted from the same star when it was traveling away from us.

That logic is incorrect since relative to the binary stars, they are not moving and we are orbiting the binary stars. By viewing the stars as motionless, it becomes clear that while we orbit the binary stars, we are running into the light of one star as we are running away from the light from the other star. Relative to the binary stars, their light is not approaching us at different speeds; we are approaching the light at different speeds. This proves that the speed of light can be based off the speed of the star without disturbing our perceptual view of the orbits.

Maxwell stated that all types of light would have a frequency that is inversely proportionate to its wavelength. Einstein believed that an increase in frequency caused by traveling towards the light source would cause an inversely proportionate change in the wavelength. What Maxwell meant was that since all types of light travel from the source at the same speed, than while at rest relative to the source, any light with a high frequency will have a short wavelength, and any light with a low frequency will have a long wavelength since multiplying them together must equal the speed of light. He did not mean that a perceptual change in frequency caused by the observer’s speed would change the wavelength.

The wavelength of light is not a relative measurement; it is the distance that the light has to travel away from the source in order to complete one wave. That distance is not determined by the observer’s speed, it is the same for all observers traveling at any speed or direction. The frequency of light is a relative measurement; it is the number of wavelengths the observer passes in one second. This number is determined by the speed of the observation and will be different between observers traveling at different speeds relative to the source. The wavelength of light is unaffected by the observers speed, any measured change in wavelength is an error that is caused by not including the distance the observer has traveled relative to the source. When calculating the wavelength, the distance that the light travels from the source in one second must be added to the distance the observer has traveled relative to the source in one second, and then divided by the measured frequency. If the distance the observer has traveled is not included, then the relative speed will never change since the total distance traveled would only include the distance the light has traveled.

In order to accurately measure the relative speed between two objects, the distance traveled by both objects in the same amount of time must be included. Interferometers and oscilloscopes only account for the distance that the light has traveled, both need to be adjusted to include the distance traveled by the observer relative to the source. An observer using an interferometer moves a mirror a specific amount of distance while counting the number of changes in the pattern of interference fringes. When used to measure wavelengths while in motion relative to the light source, the scale used to measure the distance that the mirror has moved must be adjusted to include the distance the observer has traveled relative to the source. If the observer is traveling towards the source, the same amount of movement of the mirror will represent a larger distance since it now includes the distance the observer has traveled. If the observer’s distance is not included, any increase in frequency caused by the observer’s speed will appear to decrease the wavelength causing the speed to remain unchanged.

Traveling towards the source will increase the number of waves displayed on the screen of an oscilloscope. Displaying more waves in the same amount of space means the length of each wave displayed on the screen will be reduced. This does not mean that traveling towards the source will reduce the actual length of the waves. The oscilloscope shows the waves closer together because the total distance that the screen represents has been increased to include the distance the observer has traveled relative to the source. Traveling towards the source causes the oscilloscope to use a smaller amount of the screen to represent the same amount of distance. If the distance is not included, any increase in frequency caused by the observer’s speed will appear to decrease the wavelength causing the speed to remain unchanged. While at rest relative to the source, a one second screen of an oscilloscope will represent 186,000 miles. If the oscilloscope is traveling 1,000 miles per second towards the source, then the screen of the oscilloscope must represent 187,000 miles.

Traveling towards the light does not change the distance that the light has to travel to complete one wave, just as traveling towards an oncoming train does not reduce the length of the boxcars. Traveling towards the train will increase the number of boxcars that are passed and it will increase the relative speed between the observer and the train, but it will not change the length of the boxcars. If the observer plotted the number of boxcars that passed in one minute on a four-inch line, and then did the same thing after increasing speed towards the train, the second experiment would have more marks on the four-inch line and they would be closer together. This does not mean the length of the boxcars have gotten shorter, it means that the four-inch line represents a greater distance while traveling towards the source than it does when not moving relative to the source.

The increase in measured frequency caused by the observer’s speed is equal to the distance the observer has traveled (in one-second) towards the source, divided by the known wavelength. When calculating the wavelength using the measured frequency, it must be divided into the sum of “the distance light has traveled away from the source in one second” plus “the distance the observer has traveled towards the source in one second”. When measuring the wavelength, the scale of the tool used to measure the length must account for the distance the observer has traveled relative to the source. While in motion relative to the source, the wavelength or frequency will always be divided into a number that is greater than or less than 186,000 miles, but never equal to 186,000 miles. The frequency multiplied by the wavelength must equal the sum of “the distance that the observer has traveled relative to the source in one second” plus “the distance the light has traveled relative to the source in one second”.

The speed of light is not constant to all observers, and it is not the universal speed limit. Traveling at relativistic speeds will not alter time, lengths, or mass. The Doppler effect is not a stretching or compressing of the wavelengths; it is an increase or decrease in frequency and relative speed. The only way the speed of light can be measured constant between observers traveling at different speeds is to measure a change in the length of the wave. The only way to measure a change in wavelength caused by the observer’s speed is by not including the distance the observer has traveled relative to the source. If the distance the observer has traveled is not included when measuring the speed of the train, then the speed of the train will never change. If the distance the observer has traveled is not included when measuring the speed of the light, then the speed of the light will never change. The Special Theory of Relativity is interesting, but incorrect.

In my opinion, Einstein created the Special Theory of Relativity because he misunderstood the following facts. Frequency and wavelength are only inversely proportionate when measured at rest relative to the source. When measuring the relative speed of light, the distance the observer has traveled relative to the source must be included with the distance that the light has traveled away from the source in the same amount of time. Light travels at about 186,000 miles per second relative to the source. Relative to the orbiting binary stars, we are circling them and are running into the light at different speeds (actually different distances), which explains why we don’t see multiple images of the same star. The wavelength, or the distance light travels away from the source in order to complete one cycle, is not a relative measurement and it cannot be altered by changing speed or direction. Traveling past a wavelength at a faster rate does not mean the light has traveled a shorter distance from the source to complete one cycle. Changing speed relative to the source can only change the number of wavelengths passed and the relative speed of light, not the distance the light has traveled relative to the source. It is not the speed of light that remains constant it’s the wavelength.

Thank you, Grounded. I have read through your post only once so far, but your
explaination seems clear, concise and LOGICAL to me. You have my support, although
that means nothing as I am not a physicist. Do any of the real physicists here find
any errors in Grounded's presentation, other than lacking mathematical examples? I
wonder how it would fare against Special Relativity using Occam's Razor if SR were
not so intertwined in today's physics and SR's mathematics were not so loved for
their 'exquisite' nature?

In my opinion, Einstein created the Special Theory of Relativity because he misunderstood the following facts. Frequency and wavelength are only inversely proportionate when measured at rest relative to the source.

The relevant equation is:

c = fL,

where f is the frequency of the light, L is the wavelength and c is the speed.

The theory of relativity is based on two postulates:

1. The laws of physics are form-invariant in all inertial reference frames.
2. The speed of light is constant for all observers, regardless of their state of motion.

From postulate 2, c is constant in the equation c=fL. From postulate 1, if we look at the equation in a different inertial reference frame, it becomes c=f'L'.

Thus, we conclude that f' is inversely proportional to L' in all inertial reference frames. The observer need not be stationary relative to the source.

The quoted part of your post is therefore incorrect, unless you wish to dispute one or both of the postulates of relativity. So, which is it that you think is wrong - postulate 1, or 2, or both?

I can't speak for Grounded, but I think he already answered your question in the last
sentence of his post, James R.

You're right, 2inquisitive. It seems he wants to throw away the constancy of the speed of light. Unfortunately for him, there is considerable evidence that the speed of light is indeed constant.

But did you read his ENTIRE post? Grounded explains how that evidence can have
an alternate explaination and exactly HOW it can.

grounded:

Einstein wrote that the speed of light does not depend on the speed of the object emitting the light. To prove this, Einstein referred to De Sitter’s observation of the binary stars, which are two stars that are orbiting each other.

Actually, in his original paper on special relativity, Einstein did not refer to any observations. Rather, he postulated the constancy of the speed of light. He showed that solved the problem of the lack of invariance of Maxwell's equations for the propagation of light under the Galilean tranformations, since these tranformations must rightly be replaced by the Lorentz transformations, given the postulates of relativity.

Maxwell stated that all types of light would have a frequency that is inversely proportionate to its wavelength. Einstein believed that an increase in frequency caused by traveling towards the light source would cause an inversely proportionate change in the wavelength. What Maxwell meant was that since all types of light travel from the source at the same speed, than while at rest relative to the source, any light with a high frequency will have a short wavelength, and any light with a low frequency will have a long wavelength since multiplying them together must equal the speed of light. He did not mean that a perceptual change in frequency caused by the observer’s speed would change the wavelength.

You are correct. Maxwell was not aware of the Lorentz transformations.

The wavelength of light is not a relative measurement; it is the distance that the light has to travel away from the source in order to complete one wave.

Einstein showed that this distance is related the observer's speed.

That distance is not determined by the observer’s speed, it is the same for all observers traveling at any speed or direction.

That is the Newtonian or Galilean theory. If you use that theory, you find that Maxwell's equations are not form-invariant when you change to a different frame of reference. In fact, the equations become inconsistent. There are only two ways around this problem:

1. Postulate an absolute standard of rest, which is the only frame in which Maxwell's equations apply; or
2. Throw out the Galilean transformations and replace them with a set of transformations (the Lorentz transformations) which leaves Maxwell's equations invariant in all inertial reference frames.

Since the evidence is against the existence of an absolute standard of rest, option (2) is the preferable option.

2inquisitive: Thanks for reading and protecting it...


James R: Could I pick your brain on the following?

Is it that you don’t believe the number of cycle on the screen of an oscilloscope will increase as you increase speed towards the source?

Or is it that you don’t believe the distance the observer has traveled has to be included when making relative measurements?

Hi Grounded,
You've obviously put a lot of thought into your position. That's great! I love an independent thinker.
I am concerned, however, that you are a little too attached to your position (it happens a lot, I'm afraid). I'd like you to look again at the predicitons of Maxwell's equations, and perhaps at the writings of other scientists at the time, including but not limited to Einstein. I'd avoid popular accounts of Einstein's work - there are too many works that are biased one way or the other, and give a distorted picture of the theory surrounding SR.

Are you confusing Doppler shift with relativity?

Is it that you don’t believe the number of cycle on the screen of an oscilloscope will increase as you increase speed towards the source?
The observed frequency of a signal will increase when the source and observer are approaching each other, and will decrease when the source and observer are departing from each other.
This is the Doppler effect.

Note that SR says that length contracts for both motion towards and motion away.

Or is it that you don’t believe the distance the observer has traveled has to be included when making relative measurements?
Of course it does. Length contraction is what is observed after taking all such effects into account.

Grounded:

Is it that you don’t believe the number of cycle on the screen of an oscilloscope will increase as you increase speed towards the source?

As Pete says, that's the Doppler effect. Interestingly, though, the relativistic Doppler effect formula differs from the Newtonian one, because the relativistic one is adjusted for time dilation effects. The tests have been done to see which one is correct, and guess what - relativity wins again.

Or is it that you don’t believe the distance the observer has traveled has to be included when making relative measurements?

Measurements of what? Sometimes you need to take distance into account; sometimes you don't. It depends.

Pete, James R, can I ask a question? When an observer on board a spaceship is travelling toward a light source, he will see an increase in the frequency of the
light from that source, correct? Doppler shift, of course. According to Special Relativity, will he also see a decrease in the light's wavelength from his moving
frame of reference? If not, how is the frequency separated from the wavelength
in an oscilloscope, interferometer and so on?

Pete, James R, can I ask a question? When an observer on board a spaceship is travelling toward a light source, he will see an increase in the frequency of the light from that source, correct? Doppler shift, of course. According to Special Relativity, will he also see a decrease in the light's wavelength from his moving frame of reference?

Yes. Frequency * Wavelength = c

2inquisitive,

You are correct that there are two contributions to the Doppler effect in relativity - relative movement of the source and observer (same as Newtonian physics), plus length contraction (or time dilation, depending on how you want to look at the problem).

You do realise that frequency and wavelength are two different things, don't you? The frequency of a wave is the number of wave fronts passing a point every second. The wavelength is the distance between wave crests.

The interesting thing about Maxwell's equations is that they present a specific speed of light in a vaccuum independent of the source - a changing electric field generates a changing magnetic field, which generates a changing electric field, and so on.

I think that the only meaningful interpretations of this specific speed is either:
1) The speed of light is constant relative to some medium that permeates the vaccuum itself (aether), or
2) The speed of light is constant relative to the observer. Any observer.

Yes, James R, I am very much aware that frequency and wavelength are two different
things. That is the crux of my questioning. OK, I don't want to put words in anyone's mouth, but if I understand you correctly, an observer moving toward a light source
will see an increase in the frequency of the light from that source and a decrease
in the wavelength. If the velocity of light is always measured the same by the
observer, why does he measure a decrease in the wavelength? Wouldn't that imply
the observer is moving relative to the light, that the wavelength remains unchanged
from the source of propagation, thus its constant velocity of 'c' from that source,
but if the moving observer sees the wavelength reduce, he is obvously moving toward
the light and the light's velocity is not a constant. For speed of light to be a constant regardless
of the observer's speed, the observer would have to measure the wavelength to be
the same whether he is moving or not, correct?

Pete,

think that the only meaningful interpretations of this specific speed is either:
1) The speed of light is constant relative to some medium that permeates the vaccuum itself (aether), or

I personally believe that the medium you are referring to may be gravitational fields. For example, if photons use gravitational fields for propulsion then their speeds would be constant only relative to the gravitational field that they are passing through. Since all of the aether-detection experiments that were done over the years (Michelson-Morley, Miller, etc) have been done on the surface of the Earth, stationairy in the Earth's gravitational field, it should not be surprising that the speed of light measured in those experiments was always constant (if you disregard the small effects of the Sun's gravitational field on the light in those experiments).

Also, if this is true, then the internal speed of light in an object that is travelling through a gravitational field will change as well. Mathematically, the faster the object would be travelling through the field, the smaller the average speed of light would be in that object. Since some of the fundamental forces, like the electromagnetic force, are the result of an exchange of light-speed virtual particles, the decrease of the average speed of those particles in an object that is moving through a gravitational field would cause a decrease in the strength of those fields. The decreased strength of those fields would, in turn, result in reactions occuring at a slower rate in that object than if that same object was stationairy in a gravitational field. This could explain why atomic clocks travelling through gravitational fields tick slower, and why the decay rates of particles travelling through gravitational fields at high speeds, like particles arriving from space or particles in particle accelerators, decrease.

Of course, if I'm correct, then gravity has to be more than just curved space-time, and gravitons don't exist (since there would be nothing to propel them). Also you can deduce that photons would have to have irregular gravitational fields (perhaps dipolar) that would allow external gravitational fields to influence them. However, these assumptions would be easier to accept than the psuedophysical and paranormal phenomena called length contraction and time dilation. :)

Pete, ........................."
However, these assumptions would be easier to accept than the psuedophysical and paranormal phenomena called length contraction and time dilation." :)


HeHeHe. Oh Yea.

Pete, ........................."
However, these assumptions would be easier to accept than the psuedophysical and paranormal phenomena called length contraction and time dilation."


I don't understand why giving the space-time a metric structure like in SR is more unphysical than giving it a fiber-bundle structure like in Galilean relativity, with time as the main manifold, the space as bundles and the trajectories as cross sections.
Only when you don't understand the meaning of relativity, you don't understand the meaning of length contraction and time dilation.


HeHeHe. Oh Yea.
Plz explain me what is so funny in not understanding SR

Einstein wrote that the speed of light does not depend on the speed of the object emitting the light. To prove this, Einstein referred to De Sitter’s observation of the binary stars, which are two stars that are orbiting each other. De Sitter concluded that if the speed of light were dependant on the speed of the star, then the light emitted from the star as it is traveling towards us would eventually catch up to the light that was emitted from the same star when it was traveling away from us.

That logic is incorrect since relative to the binary stars, they are not moving and we are orbiting the binary stars. By viewing the stars as motionless, it becomes clear that while we orbit the binary stars, we are running into the light of one star as we are running away from the light from the other star. Relative to the binary stars, their light is not approaching us at different speeds; we are approaching the light at different speeds. This proves that the speed of light can be based off the speed of the star without disturbing our perceptual view of the orbits.


This logic is indeed correct, since, if we have two binary stars (I mean two pairs), that have each one a different velocity relative to us, you cannot say that both are motionless.At least one of the binary star will be in motion relative to the other and then, if the speed of light depends on the sources velocity, at least, for one of them (the one that is not motionless), the effect described by DeSitter will hapen

I am concerned, however, that you are a little too attached to your position.

I only stand by it because it is logical and it works.

An observer traveling towards a source of light will measure an increase in frequency. We call this Doppler shift, which is caused by passing the wavelengths at a faster rate. We also measure a decrease in wavelength, which is said to be an effect of the relativity.

What I see is that the only reason we measure a decrease in the wavelength is because we are not including the distance the observer has traveled.

If the distance the observer has traveled relative to the source is included, then the wavelength will not change and the speed of light will not be constant. The only reason we measure the speed of light to be constant is because we measure a change in the wavelength.

Run some real or theoretical experiments with the formulas below, you will find they work.

Change in frequency:
The amount of change in the measured frequency caused by the observer’s speed relative to the source is equal to the distance the observer has traveled relative to the source in one second (“positive when traveling towards the source” “negative when traveling away from the source”), divided by the known wavelength.

Observer’s speed:
The speed of the observer (relative to the source) equals the measured frequency multiplied by the known wavelength, minus the speed of light.

Measured frequency:
The measured frequency equals the speed of light added to the speed of the observer relative to the source (“positive when traveling towards the source” “negative when traveling away from the source”), divided by the known wavelength.

True wavelength:
The wavelength (relative to everyone) equals the speed of the observer relative to the source (“positive when traveling towards the source” “negative when traveling away from the source”) added to the speed of light, divided by the measured frequency.

Plz explain me what is so funny in not understanding SR

Don't be so sensative. I was ammused by his choice of adjectives. :D

2inquisitive:

OK, I don't want to put words in anyone's mouth, but if I understand you correctly, an observer moving toward a light source will see an increase in the frequency of the light from that source and a decrease in the wavelength. If the velocity of light is always measured the same by the observer, why does he measure a decrease in the wavelength?

That is a purely relativistic effect. The observed decrease in wavelength is due to the relative speed between the observer and the wave - i.e. relativistic length contraction. The effect is insignificant in cases where the speed of the observer relative to the wave is much less than the speed of light.

Does an Earth-based observer see this length contraction if the approaching wavelength is from an object (galaxy or whatever) that moving toward Earth at
a large relative velocity? If so, why is the same relativistic effect (contraction) not
seen by the Earth-based observer when looking at a relativistically moving spacecraft?
Ahh, but we DO see contraction of the spacecraft itself, just not the distance between us, so says SR. Next question, if we the wavelength of light decrease as we
approach its source, thus the light's increase in energy, how does this happen and
where does the energy increase come from? The light isn't increasing in velocity, so
why does its energy increase just because we move toward it?

You do see what I am getting at, don't you? If we had a spaceship capable of near-
light speeds, SR would predict visible light would increase to gamma-ray energies
if our velocity were great enough as we approached a star and the gamma-rays would
kill us. Grounded's explanation for light would have only the frequency increase with
no increase in energies, just a Doppler shift into the blue spectrum. Know anyone
that has a spaceship capable of such speed so we could check it out?

why does its energy increase just because we move toward it?

Energy is also relative. Consider a brick wall, moving slowly. Now move toward it, as fast as you can...

But Pete, when we run toward the brick wall, we are increasing the relative velocity
between us and the wall. In SR, the relative velocity remains the same, 186,000 miles
per second. We do not approach the light any faster, the velocity of light remains constant in SR. So what is the energy relative to?

Now, using James and, I assume, SR's explanation for the reduction in wavelength,
the increased energy would come from length contraction of the wavelength due
to velocity. So, even though we can't use velocity addition to increase lights' speed,
we can use it to increase light's energy, correct?

But Pete, when we run toward the brick wall, we are increasing the relative velocity
between us and the wall. In SR, the relative velocity remains the same, 186,000 miles
per second. We do not approach the light any faster, the velocity of light remains constant in SR. So what is the energy relative to?

Photon energy is dependent on frequency, not velocity.

E = h.f

If you don't accept that, consider this analogy:

Imagine a long trough carrying petroleum toward you. You collect the petroleum, and extract energy from it.
Now, move along the trough, against the flow of the petroleum.
How much energy can you extract now? Don't be distracted by the change in relative velocity here - the energy content of the fuel is independent of its velocity.

I only stand by it because it is logical and it works.

An observer traveling towards a source of light will measure an increase in frequency. We call this Doppler shift, which is caused by passing the wavelengths at a faster rate. We also measure a decrease in wavelength, which is said to be an effect of the relativity.

Grounded, I agree that the decrease in wavelength is primarily an effect of the Doppler shift, not of relativity.
I think that wavelength changes are only slightly altered by relativistic considerations.

That is a purely relativistic effect. The observed decrease in wavelength is due to the relative speed between the observer and the wave - i.e. relativistic length contraction. The effect is insignificant in cases where the speed of the observer relative to the wave is much less than the speed of light.

What?
Surely the change in wavelength is significant whenever the change in frequency is significant?

wavelength x frequency = c, right?

by Pete:

"Photon energy is dependent on frequency, not velocity."
===============================================

I was under the impression light's energy was dependent upon its wavelength, not
its frequency. I thought the energy of a photon was related to its RADIATION frequency, not the kind of frequency increase we see by increasing our relative
velocity toward light in the wave form.

by Pete:

"Photon energy is dependent on frequency, not velocity."
===============================================

I was under the impression light's energy was dependent upon its wavelength, not
its frequency. I thought the energy of a photon was related to its RADIATION frequency, not the kind of frequency increase we see by increasing our relative
velocity toward light in the wave form.
No, according to QM, the energy is related to the frequency, while the momentum is related to the wavelength.

In light viewed as a wave, energy is related to its wavelength. Frequency is only
counting the number of wavepoints that pass each second. In light viewed as a
photon, frequency is its radiation intensity, the higher its frequency the higher its
energy. How do we increase this frequency by relative velocity when, according to SR, there is no increase in relative velocity?

2inquisitive:

In light viewed as a wave, energy is related to its wavelength.

In the photon picture of light, a single photon has energy hf=hc/L, so the photon energy is associated with either frequency or wavelength. The total energy of a bunch of photons depends both on the energy of each individual photon and the number of photons passing a point each second.

In the classical wave picture of light, the energy of the wave is related to the wave amplitude.

Frequency is only counting the number of wavepoints that pass each second. In light viewed as a photon, frequency is its radiation intensity, the higher its frequency the higher its energy.

In the photon picture, intensity has nothing to do with frequency. Intensity depends on the number of photons passing a point each second.

James, you seem to want to speak of only the brightness, or intensity (same thing)
of light. Wavelength describes what TYPE of light it is, from a radio wave to a gamma
ray. Do you not agree that a gamma ray is a more energetic form of light than a radio
wave? The amplitude of a lightwave is the wave height, either above or below a zero
point in the middle of the wave. It is a measure of brightness or intensity of the wave.
That wouldn't change due to relative velocity. In the photon picture, a single photon
of one color differs from a photon of another color only by its energy. A gamma ray
photon is much more energetic than a radio wave photon. I misused 'intensity' when I
spoke of 'radiation intensity' in relation to energy. I meant a higher frequency radiation
when I said radiation intensity, which was wrong termonology. But, back to the point.
Does moving toward, or away, from a light source at relativistic speeds affect the
physical properties of light according to Special Relativity? Does relative velocity cause
the light to be preceived as more or less energetic, according to whether the separation between the source and the observer is increasing or decreasing? And,
remember, blue light is more 'energetic' than red light.

Some 'speculation' on my part. The 'oldest' known galaxy so far is 13.23 billion years,
according to the accepted method of postulating light always arrives at 'c' regardless
of recessional velocity of the emitting object, that light is always supposed to travel
at 299,792,458 m/s whether measured by us, the observer, or by the emitting galaxy.
That means the galaxy was fully formed and emitted the light we are receiving only
470 million years after the Big Bang. It is also a method of measuring distance, so
the galaxy could be said to have been 13.23 billion light years in distance from us
when the light was emitted. According to accepted physics, 470 million years is not
enough time for a galaxy to form. And how did the galaxy get to be so distant from
us in only 470 million years after the Big Bang? I believe light always travels at
299,792,458 m/s from its emitting source. The galaxy in question had a great recessional velocity relative to us. Subtract this recessional velocity from 299,792,458
m/s and you have the true speed of light RELATIVE TO US, the observer. It took the
light 13.23 billion years to reach us because, relative to us, its velocity was slow.
The galaxy was much older than 470 million years old when the light was emitted and
much closer than 13.23 light years away. The recessional velocity of the galaxy can
be calculated by Doppler shift, as Grounded indicated above. The true age and the
true distance to the galaxy can be calculated. Do you think there will be no galaxies
older or more distant than this one as our technology improves? I believe there will be.
If we are currently overestimating the distance to galaxies by assuming light always
arrives at 'c' in relation to us, it would indicate there are no galaxies receeding from
us at greater than the speed of light. The observable universe would be much smaller
than current estimates and it would not be expanding at an accelerating rate, requiring
Dark Energy. The Big Bang and expansion would still be acceptable, but the rate of
expansion would decrease from current estimates and probably result in a slowing rate
of expansion. General Relativity was accepted before Special Relativity and is not
dependent on SR to survive. I believe light to propagate at 299,792,458 m/s from its
source, but I do not believe it to travel at that same velocity relative to every observer.
The changing physical properties of light relative to its source are actually a measure
of its velocity relative to the observer. I know this is not the 'accepted' way to view
light and physics, but I think it may be closer to reality than Special Relativity. And
yes, I know my viewpoint is flawed because I don't 'understand' relativity and, no, I
don't claim to be 'smarter' than all the physicists, but maybe I do believe this is a
more 'logical' viewpoint, for me at least.

2inquisitive:

Does moving toward, or away, from a light source at relativistic speeds affect the physical properties of light according to Special Relativity? Does relative velocity cause the light to be preceived as more or less energetic, according to whether the separation between the source and the observer is increasing or decreasing? And,
remember, blue light is more 'energetic' than red light.

Yes, it does. If you move towards a light source, its photons become more energetic, as seen by you. And vice versa if you move away from the source.

That's nothing particualr to light, by the way. If you move towards a stationary rock, it gains kinetic energy according to you, so it becomes more energetic too. Energy is a frame-dependent quantity.

2inquisitive:

Yes, it does. If you move towards a light source, its photons become more energetic, as seen by you. And vice versa if you move away from the source.

That's nothing particualr to light, by the way. If you move towards a stationary rock, it gains kinetic energy according to you, so it becomes more energetic too. Energy is a frame-dependent quantity.

Not to side track this topic but to simply add a note.

That is why I have come to view light as a quantum energy function at the Lorentz Contraction point of "zero" dimension. An observers motion relative to the source alters the production or observation of light and explains the "apparent" invariance of its speed.

Experiments should be run in flowing fluids and particle accelerators using Cerenkov Radiation to study the affect and cause of light invariance. It is now possible infact to use a flowing condensate and observer actual light invariance at speeds of a few miles per hour or less.!

That would be most interesting. If you wish to comment on this please start another thread.

Light as a wave. Light has a wavelength, a frequency, and an amplitude (heigth). It also has energy and momentum.
What part of light is invariant to relative velocity other than its heigth?

And, by the way James, when we move toward that rock, how do we increase its
kinetic energy? Don't we have to change the relative velocity between us and the
rock?

Mac, I do not now, and have not in the past, believe the speed of light is invariant
TO THE OBSERVER. It is invariant from its source, only. That is why I do not personally
support any theory that depends on the speed of light relative to the observer as constant.
That is why I support Grounded's explanation and believe it to be true. Mac, you do
realize General Relativity is not dependent on the invariance of the speed of light,
don't you? You just always say 'relativity', but SR and GR are two different beasts.

Mac, I do not now, and have not in the past, believe the speed of light is invariant
TO THE OBSERVER. It is invariant from its source, only. That is why I do not personally
support any theory that depends on the speed of light relative to the observer as constant.
That is why I support Grounded's explanation and believe it to be true. Mac, you do
realize General Relativity is not dependent on the invariance of the speed of light,
don't you? You just always say 'relativity', but SR and GR are two different beasts.
In GR, in all frames, for light we have ds²=0. This means that in GR, in all reference frames, the speed of light is the same.

2inquisitive:

What part of light is invariant to relative velocity other than its height?

Its velocity. Oh, and amplitude has nothing to do with height. The amplitude of a light wave relates to the strengths of the electric and magnetic fields making up the wave.

And, by the way James, when we move toward that rock, how do we increase its kinetic energy? Don't we have to change the relative velocity between us and the
rock?

Yes, and that's exactly what you do when you move towards the rock. Start with the rock stationary relative to you. It's speed is zero. Now, start running towards it at speed v. According to you, the rock is now approaching you at speed v. Before you started running, the rock had zero kinetic energy; now it has energy (1/2)mv², where m is the mass of the rock.

Mac, I do not now, and have not in the past, believe the speed of light is invariant TO THE OBSERVER.

Your belief is worthless, since all the evidence is against it. Do you have a BASIS for your belief, or just a gut feeling, like MacM?

It is invariant from its source, only.

What on Earth does that mean?

That is why I support Grounded's explanation and believe it to be true. Mac, you do realize General Relativity is not dependent on the invariance of the speed of light, don't you? You just always say 'relativity', but SR and GR are two different beasts.

SR is a subset of GR. The constancy of the speed of light is therefore as much a part of GR as it is of SR.

You must have a different definition for the definition of a light wave than I have yet
seen. Just one, from Univ. of CA, Berkley, The Light Universe:

"Here is the definition of wave amplitude that scientists use!

Amplitude is a measurement of the top (or bottom) half of the wave.

What does it mean?
If there were no light wave at all, these graphs would be flat, like a string before it is plucked. Call that the zero position*. When you pluck a string, you pull it away from zero position by a certain distance, called the amplitude, using a certain amount of energy. Afterwards, as the string vibrates, its wave peaks go back to (but not beyond) that original size, until the wave starts to lose energy (die down). That distance from the zero position to the top of every wave peak always tells how much energy is left in the wave. In the same way, the amplitude of a light wave is also a measure of how much energy the wave carries.
Why only half?
Scientists like to call the middle point zero, so that the bottom half of the wave has a negative value, like -0.7 or -1. But energy is something positive, so the measure from zero to the peak, which is always positive, is what we use. The bottom half shows the same amount of energy, and the distance is the same. Since we always use the distance from zero to the peak, we can always compare amplitudes of different waves without getting confused about plus or minus."
http://cse.ssl.berkeley.edu/light/measure3.html
================================================== ===========

Yes, James, I know the 'velocity' is what is supposed to be invariant, I asked what part
of light, i.e. its components, are invariant. Is the wavelength constant for all observers? Is the frequency? Is the energy? Only the amplitude, the wave HEIGTH is
is invariant. Is the group velocity? Is the phase velocity? What physical component
of the lightwave is invariant? And just like the rock, we have to change the relative
velocity between us and the lightwave to change its energy, the relative velocity of
light is not invariant. When I said the speed of light was invariant from its source, only,
that is exactly what it means. Light propogates from its source at 'c', but it does not
travel at 'c' relative to a moving observer. How many times do I have to repeat myself?

You must have a different definition for the definition of a light wave than I have yet
seen. Just one, from Univ. of CA, Berkley, The Light Universe:

"Here is the definition of wave amplitude that scientists use!

Amplitude is a measurement of the top (or bottom) half of the wave.

What does it mean?
If there were no light wave at all, these graphs would be flat, like a string before it is plucked. Call that the zero position*. When you pluck a string, you pull it away from zero position by a certain distance, called the amplitude, using a certain amount of energy. Afterwards, as the string vibrates, its wave peaks go back to (but not beyond) that original size, until the wave starts to lose energy (die down). That distance from the zero position to the top of every wave peak always tells how much energy is left in the wave. In the same way, the amplitude of a light wave is also a measure of how much energy the wave carries.
Why only half?
Scientists like to call the middle point zero, so that the bottom half of the wave has a negative value, like -0.7 or -1. But energy is something positive, so the measure from zero to the peak, which is always positive, is what we use. The bottom half shows the same amount of energy, and the distance is the same. Since we always use the distance from zero to the peak, we can always compare amplitudes of different waves without getting confused about plus or minus."
http://cse.ssl.berkeley.edu/light/measure3.html
================================================== ===========

Note tat in the graphs that are shown, there is no unit on the "y" axis.
The same graph represents a sound wave, a wave on a string or the electric field of a light wave.
In a string, you can compare the amplitude with height since the amplitude is really given as a length unit. In a sound wave, the "y" axis will be measured in pression unit. In the graph, it will be in the y direction, however, the motion of the particles will be in the direction of propagation (this is what is called a longitudinal wave). For the electric field, the y axis will be in electric field units (V/m for example). The electric field is a vector and the direction of this vector (at least in vacuum) will be orthogonal to the direction of propagation. So you see that the amplitude of a wave has nothing to do with height.


Yes, James, I know the 'velocity' is what is supposed to be invariant, I asked what part
of light, i.e. its components, are invariant. Is the wavelength constant for all observers? Is the frequency? Is the energy? Only the amplitude, the wave HEIGTH is
is invariant. Is the group velocity? Is the phase velocity? What physical component
of the lightwave is invariant? And just like the rock, we have to change the relative
velocity between us and the lightwave to change its energy, the relative velocity of
light is not invariant. When I said the speed of light was invariant from its source, only,
that is exactly what it means. Light propogates from its source at 'c', but it does not
travel at 'c' relative to a moving observer. How many times do I have to repeat myself?
The only thing that is invariant in light is its speed. If you want to know how the amplitude, frequency etc. change as we change from one reference frame into another you must transform the electromagnetic.
In fact the electric field and the magnetic field are different parts of the same field: the elctromagnetic field. The electromagnetic field is a second rank tensor, and the transformation of a second rank tensor is known. Apllying this transformation will give you the way that the electromagnetic field is transformed as we change reference frame.

BTW, you can repeat as many times as you want that earth is flat and is on the back of giants elephants, it does not make it right, since experiment show that there are no elephants that support the earth on their back, you can also repeat many times that the speed of light depends on the source, that does not make it right, since experiment show that the speed of light is constant and does not depend on the source velocity

1100f, amplitude is also a property of a transverse wave, a light wave. A light wave
has two components of course, a magnetic component and an electric component,
and the amplitude can apply to either component separately, if need be. Polarised
light is an example. The magnetic component of the wave has been blocked. Amplitude
refers to the 'pulse' that is orthogonal to the direction of movement, the 'hump' in the
wave. It is a displacement of a medium, yes, even in a transverse wave, the displacement is orthogonal to the direction of movement instead of parallel to the wave. The amplitude is a measure of the displacement and can be expressed as 'height'
above the zero point, or midsection, of the wave. It could be measured from the
'y' axis or the 'z' axis, or both, of a wave propagating in the 'x' direction. Wave heigth
is putting a numerical value to this displacement. A radio wave is 'taller' than an ultraviolent wave and is expressed as the wave heigth. Combined with wave length
and frequency, the energy of the wave is determined. I made a statement that 'It is
invariant to the observer, only' which James R copied out of context and asked 'What on Earth does that mean?' That was why I asked how many times do I have to repeat
myself. That is a tactic that I did not think James R would use, as I haven't taken any
of his statements out of context.

2inquisitive:

1100f, amplitude is also a property of a transverse wave, a light wave. A light wave has two components of course, a magnetic component and an electric component, and the amplitude can apply to either component separately, if need be.

The amplitudes of the electric and magnetic fields in a light wave are related by B=E/c, where B is the magnetic amplitude and E the electric. c is the speed of light, which is constant.

Polarised light is an example. The magnetic component of the wave has been blocked.

That is wrong. All light waves have both electric and magnetic components. If you block either component, you kill the wave.

Amplitude refers to the 'pulse' that is orthogonal to the direction of movement, the 'hump' in the wave. It is a displacement of a medium, yes, even in a transverse wave, the displacement is orthogonal to the direction of movement instead of parallel to the wave. The amplitude is a measure of the displacement and can be expressed as 'height' above the zero point, or midsection, of the wave. It could be measured from the 'y' axis or the 'z' axis, or both, of a wave propagating in the 'x' direction. Wave heigth is putting a numerical value to this displacement.

Right so far...

A radio wave is 'taller' than an ultraviolent wave and is expressed as the wave heigth.

Wrong. The only difference is frequency, which is independent of the amplitude for a classical wave.

Combined with wave length and frequency, the energy of the wave is determined.

The energy is independent of the frequency and wavelength for a classical wave.

I made a statement that 'It is invariant to the observer, only' which James R copied out of context and asked 'What on Earth does that mean?'

I did not take it out of context, and I still don't know what you mean.

an excerpt from Grounded's first post:

"What Maxwell meant was that since all types of light travel from the source at the same speed, than while at rest relative to the source, any light with a high frequency will have a short wavelength, and any light with a low frequency will have a long wavelength since multiplying them together must equal the speed of light. He did not mean that a perceptual change in frequency caused by the observer’s speed would change the wavelength.

The wavelength of light is not a relative measurement; it is the distance that the light has to travel away from the source in order to complete one wave. That distance is not determined by the observer’s speed, it is the same for all observers traveling at any speed or direction. The frequency of light is a relative measurement; it is the number of wavelengths the observer passes in one second. This number is determined by the speed of the observation and will be different between observers traveling at different speeds relative to the source. The wavelength of light is unaffected by the observers speed, any measured change in wavelength is an error that is caused by not including the distance the observer has traveled relative to the source."
================================================== ========

This is Grounded's thread. I happen to agree with him, as I have indicated all along.
It is not in agreement with the currently accepted 'theory' that light is invariant in
velocity to all observers and the speed of the propagating source of the light makes
no difference. Special Relativity postulates that the OBSERVER always sees EM radiation (light) travel at 'c', which is 299,792,458 m/s. SR postulates that even if
light is emitted from a source receeding from the observer at .99c, the light will still
travel at 299,792,458 m/s relative to the observer over the entire distance and time
the light travels, irregardless of the relative velocity between observer and the source
of the light. I, Grounded, and Maxwell state that the light will always travel at 'c'
from the source the light was emitted from, the star or whatever. Light is invariant
from its source, but it is NOT invariant to the observer. Grounded gives a clear and
easy to understand explanation of why past experiments have been in error when
measuring the 'invariance in the speed of light by the observer'. For example, Mickleson
and Morley did NOT have a 'null' result. They measured a difference of 8 m/s in the
speed of light with their interferometer. Use Grounded's explanation of why the wavelength of light should be constant from its source, make the adjustments to the
values recorded by M&M, and the Earth's velocity should be shown by the difference.
Bouncing light off a prism or 'mirror' on the moon does confirm the speed of light to
be 299,792,458 m/s, but we are essentially in the same frame of reference, there is
no relative velocity between the Earth and the moon during the small time interval
the measurements are conducted in. The Earth is the source of the light, which travels
away at 'c' and is reflected back at 'c'. James, when you can find the time to do so,
please reread Grounded's three posts at the beginning of this thread, just his posts.
I am sure you can understand what he says, and I am also sure you will not agree
with him because of Special Relativity. But show his error, if you can. I don't believe
there is one.

I, Grounded, and Maxwell state that the light will always travel at 'c'
from the source the light was emitted from, the star or whatever.
Wrong: You and Grounded state this.
I don't believe you have ever seen Maxwell's equation if you say that they say that the speed of light depends on the source, or you didn't understand them at all

2inquisitive,


"What Maxwell meant was that since all types of light travel from the source at the same speed, than while at rest relative to the source, any light with a high frequency will have a short wavelength, and any light with a low frequency will have a long wavelength since multiplying them together must equal the speed of light. He did not mean that a perceptual change in frequency caused by the observer’s speed would change the wavelength.


The equation is: c = n l. When l change, n must be reciprocally change as well or else c no longer the same according to observers in different inertial reference frames.


The wavelength of light is not a relative measurement; it is the distance that the light has to travel away from the source in order to complete one wave. That distance is not determined by the observer’s speed, it is the same for all observers traveling at any speed or direction. The frequency of light is a relative measurement; it is the number of wavelengths the observer passes in one second. This number is determined by the speed of the observation and will be different between observers traveling at different speeds relative to the source. The wavelength of light is unaffected by the observers speed, any measured change in wavelength is an error that is caused by not including the distance the observer has traveled relative to the source."


Try to think about it like this. You are observing a star moving away from earth at velocity, say, v=0.6c. Assuming that the star emits radio wave at frequency n=2 Hz, hence l=150,000km. On earth, due to Doppler effect, you observe the frequency as 1 Hz. Now, you ask yourself, what l would you find; 150,000km or 300,000km?

If your answer is 150,000km (which I think you should, given your opinion that l is unaffected by relative velocity), then you must also measure c=150,000km/s (half of the normal speed of light).


I am sure you can understand what he says, and I am also sure you will not agree with him because of Special Relativity. But show his error, if you can. I don't believe there is one.

Since you know that Grounded's idea contradicts SR, but you believe there is no error in Graunded's idea, you should also believe that Grounded deserve a Nobel prize.

That logic is incorrect since relative to the binary stars, they are not moving and we are orbiting the binary stars.


I presume, "we" mean earth and the whole solar system. Are we (our solar system) really orbiting a binary stars? I didn't know this. Wow, a wonderful "fact".

" relative to the binary stars, they are not moving and we are orbiting the binary stars."

This simply means an observer in the binary stars frame of reference. Paul T, you might
want to reread Grounded's 1st and 3rd posts again to get some clarity on what he is
saying.

2inquisitive,


" relative to the binary stars, they are not moving and we are orbiting the binary stars."

This simply means an observer in the binary stars frame of reference. Paul T, you might
want to reread Grounded's 1st and 3rd posts again to get some clarity on what he is
saying.


No, 2inquisitive, that's not what Graunded said. Here, the quote:


Einstein wrote that the speed of light does not depend on the speed of the object emitting the light. To prove this, Einstein referred to De Sitter’s observation of the binary stars, which are two stars that are orbiting each other. De Sitter concluded that if the speed of light were dependant on the speed of the star, then the light emitted from the star as it is traveling towards us would eventually catch up to the light that was emitted from the same star when it was traveling away from us.

That logic is incorrect since relative to the binary stars, they are not moving and we are orbiting the binary stars. By viewing the stars as motionless, it becomes clear that while we orbit the binary stars, we are running into the light of one star as we are running away from the light from the other star. Relative to the binary stars, their light is not approaching us at different speeds; we are approaching the light at different speeds. This proves that the speed of light can be based off the speed of the star without disturbing our perceptual view of the orbits.


Grounded said "they are not moving and we are orbiting the binary stars". In the above quote: "they", I believe, really referred to the two stars in the binary star system and "we" referred to us (earth or our solar system).

In the previous paragraph Grounded told us about de Sitter observation on the binary star systems. I believe de Sitter that he told us is the same de Sitter described <a href="http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Sitter.html">here</a>, who I believe had never travelled to any binary star system and orbited them. Therefore, "we" mentioned by Graunded must mean "our earth" or "our solar system". If you read carefully, probably you would notice that Graunded tried to report some sort of new finding that our solar system is actually orbiting a binary star system.

There is also other peculiar history fact Grounded conveyed to us, that is about Einstein making reference to de Sitter's work to support his theory about the independency of speed of light to its source. Since Einstein published his SR paper in 1905 while de Sitter appear to made public his conclusion for his study on binary star systems in 1913, I found it is odd that Einstein relied upon de Sitter's work to support his SR. There are possibility such as, Grounded referring to Einstein statement's after 1913, which I am not aware of or Graunded again implying that may be Einstein could travel to future to read de Sitter's work and then published his 1905 paper of course without mentioning de Sitter's yet to be published work.

Paul T, relativity teaches us that a moving frame of reference is indistinguisable from
a stationary frame of reference and the same physics apply to both. Grounded's example was to imagine the binary star system as the stationary frame and our
solar system as the moving frame of reference. He did not mean the solar system
was actually orbiting a binary star system. Einstein published Special Relativity in 1905,
but SR was not accepted by the scientific community then, it was just another 'alternative' theory from a patent clerk. SR was not accepted until after
General Relativity was published in 1916 and later accepted. I assume the reference to de Sitter's work was in lectures promoting Special Relativity by Einstein after 1916.

Paul T, relativity teaches us that a moving frame of reference is indistinguisable from
a stationary frame of reference and the same physics apply to both. Grounded's example was to imagine the binary star system as the stationary frame and our
solar system as the moving frame of reference. He did not mean the solar system
was actually orbiting a binary star system. Einstein published Special Relativity in 1905,
but SR was not accepted by the scientific community then, it was just another 'alternative' theory from a patent clerk. SR was not accepted until after
General Relativity was published in 1916 and later accepted. I assume the reference to de Sitter's work was in lectures promoting Special Relativity by Einstein after 1916.
Then you should read again what Grounded claimed: he said that the velocity of light depends on the source velocity, then he said that the velocity of light that gets out of both stars is the same since they are not moving and finally that our system is orbiting around the binary star. This is exactly what he said since this is the only possibility to support his logic against de Sitter.
If it is as you said just a question of reference frame, then de Sitter hypotesis is correct.
BTW if you have one binary star from his example that is stationary, thaen, any other binary star that moves relative to the first one wil not be stationary, and what de Sitter suggested will stil be right, so that you can see that Grounded hypothesis is flawed.

I stated what I interpreted Grounded's example to be. I cannot speak for him and he does not seem interested in participating in his thread. My position stands. I cannot
alter anyone's views and you cannot alter mine. Let this thread die as there is no
solution.

I cannot speak for him and he does not seem interested in participating in his thread.

Sorry, I thought I could keep up with several sites, I was wrong.

E-mail me and I will tell you where I am. I won't post it because I don't want to offend "sciforums", my decision had nothing to do with the quality of this sight.

GroundedElectric@comcast.net

Thanks, Grounded, but an e-mail is not necessary. I came across one of your threads
at another forum last night. I don't normally frequent that site and have not registered
yet, but I may, I haven't decided yet. I did see some mistakes made by the so-called
'experts' in your thread, but I don't know if it would have much value to point them
out, just cause hard feelings. Special Relativity is a house of cards that is doomed
to fall, but it is still now surrounded by many, many knights in shining armor convinced
they are protecting it against the heretics.

Special Relativity is a house of cards that is doomed
to fall, but it is still now surrounded by many, many knights in shining armor convinced
they are protecting it against the heretics.
There are certainly those who see it that way.

There are other who see SR as a bloody obstinate rock.

We've tried crowbars, sledge hammers, jack hammers, bulldozers, dynamite, sapping mines, drills, gentle tickles, begging and pleading... But it just won't budge! It doesn't stop us trying, though. The 'establishment' that is.

Special Relativity is a house of cards that is doomed to fall, but it is still now surrounded by many, many knights in shining armor convinced they are protecting it against the heretics.

If only you had something which supported your assertion...

Special Relativity is a house of cards that is doomed
to fall, but it is still now surrounded by many, many knights in shining armor convinced
they are protecting it against the heretics.
Let me understand: you don't seem to realy understand relativity, you do not understand what Grounded said. In order to blindly support him, you gave the flaws of his assumption by thinking that you found the flaws of SR. In fact what you should have say is that:

The hate of Special Relativity is a house of cards that is doomed
to fall, but it is still now surrounded by many, many knights in shining armor convinced
they are protecting it against the heretics.

Let me understand: you don't seem to realy understand relativity, you do not understand what Grounded said. In order to blindly support him, you gave the flaws of his assumption by thinking that you found the flaws of SR. In fact what you should have say is that:

The hate of Special Relativity is a house of cards that is doomed
to fall, but it is still now surrounded by many, many knights in shining armor convinced
they are protecting it against the heretics.

Put quite a few words in my mouth there, didn't you 1100f? Let me understand, you do not understand what Grounded said, you do not really
know what Special Relativity actually is, but you support it blindly anyway.
You hate any heretic that opposes your religion.

Put quite a few words in my mouth there, didn't you 1100f? Let me understand, you do not understand what Grounded said, you do not really
know what Special Relativity actually is, but you support it blindly anyway.
You hate any heretic that opposes your religion.

Grounded said:

That logic is incorrect since relative to the binary stars, they are not moving and we are orbiting the binary stars.
You said

He did not mean the solar system
was actually orbiting a binary star system.
So I don't know why you support his claim.

Finally, you said:
Special Relativity is a house of cards that is doomed
to fall, but it is still now surrounded by many, many knights in shining armor convinced
they are protecting it against the heretics.
While you never gave anything that support this claim.

Grounded said:

You said

So I don't know why you support his claim.

Finally, you said:

While you never gave anything that support this claim.

Einstein gave a defintion of simultaneity: Events that ae simultaneous in a stationary frame are not simultaneous in a moving frame." He uses the train station and moving train as his example definition. The moving observer O' passes the midpoint of photon sources A and B in the stationary frame just as the photons are emitted from A and B.

|A-----------M------------B|
O'

The B photon is detected first then A is detected.

|-------------M------B----A-|
t0 t1 t2

O' is at each time indicated. As the photons are observed sequentially Einstein says that the passenmgers "must, therefore" conclude the photons are not emitted simultaneously in the moving frame.

Ok but the train is lengthy. Just as the photons from A and B arrive at the midpoint M after being detected at t1 but before detection at t2, the passengers P, sitting adjacent to M when the photons arrive simultaneously, the P observe the photons simultaneously arriving in the moving frame.

A ->|<-B
|--------------M------B--------]
P t1

Do you see a problem with SR now, like a glaring contradiction between defintion and observation??

And does it not seem strange that such weight is placed on this definition, like loss of absolute time, insertion of time dilation and mass shrinking?

If you replace the photons with NASCARs moving at 300km/hr and the 0bserver O' moving at 100 km/hr and the distance between AB is 800 meters, then the B Nascar will intercept O' at 100 meters passed M and the A NASCAR will intercept O' 100 metees from where B intecepted O'. Now here everbody on the rack can see the NASCAR emitting into the moving frame as soon as they leave A and B simultaneously? Will you, or anybody else conclude the two NASCARS were not emitted into the O' frame simultaneously, that is when they entered, that is left the A and B positions, not when they were detected?

So what is the difference here? Photons vs NASCARS? So what is the difference in the conclusions you draw? Saying photons aren't NASCARS begs the question because the beginning of SR starts with the simultaneity definition. Read Relativity by A Einstein, a very readable math free book.

I was looking for someplace to post this question and since this thread is quite developed ill try here...

In special relativity it is my understanding that an observer measuring the velocity of llight will always come stumble upon the same answer because when the observer is approaching the light, time must slow down because C≠ 299,792,458 m/s - V. If the observer were to instead of walking toward the light, back pedal and again try to measure the velocity of the light will time indeed speed up?
because surely C≠ 299,792,458 m/s + V

In special relativity it is my understanding that an observer measuring the velocity of llight will always come stumble upon the same answer because when the observer is approaching the light, time must slow down because C≠ 299,792,458 m/s - V. If the observer were to instead of walking toward the light, back pedal and again try to measure the velocity of the light will time indeed speed up? because surely C≠ 299,792,458 m/s + V

No, because there is a flaw in your reasoning: time does not speed up to keep the speed of light constant. If you look at it properly, you can say that it is actually the other way around. If you were to look at another, moving observer, his time slows down with respect to yours because of the constancy of the speed of light (there is an important difference in cause and effect here). That other observer himself would not see something strange btw, for him it would appear as if time were ticking normally.

This effect (time dilatation) is independent of the direction of motion, and depends only on the speed of the observer. If it puzzles you, do a search for "time dilatation" on this forum and you'll find many, many threads on it (but beware, also many, many misinterpretations of it).

2inquisitive - why don't you read up on special relativity, and learn what it says before you try to prove it wrong?
from your posts it seems that you don't really know SR.

In special relativity it is my understanding that an observer measuring the velocity of llight will always come stumble upon the same answer because when the observer is approaching the light, time must slow down because C≠ 299,792,458 m/s - V. If the observer were to instead of walking toward the light, back pedal and again try to measure the velocity of the light will time indeed speed up?
because surely C≠ 299,792,458 m/s + VIt makes no sense to say that an observer is moving toward or away from light, since light has no unique frame of reference associated with it. With respect to what is the observer moving?

If we choose an arbitrary frame of reference, then we need to replace your vtotal = v1 + v2 formula with the relativistic formula:

vtotal = (v1 + v2)/(1 + v1*v2/c^2)

and we see that if one of the velocities is c, then the total velocity will always be c, regardless of the magnitude or sign of the other velocity.

2inquisitive - why don't you read up on special relativity, and learn what it says before you try to prove it wrong?
from your posts it seems that you don't really know SR.

Shoffsta, me thinks tis yourself that needs to "read up on special relativity".

From Einstein's definition of simultaneity as described in "Relativity": Events simultaneous in a stationary freame are not simultaneous in a moving frame." This a bogus definition and is the very heart and soul of special relativity. If the definition goes, so too special relativity.
In the train gedunken the obsever O' detects the photon from B then the photon from A from behind.

A B
|__________M_______B___A_|
a0 0,2 O' 1,O'<---0b
---------------------3O'

We use numbers for the event times.
0 is the time the photons were emitted by A and B and when O' was at M the midpoint of A and B and recorded by a and b in the moving frame.
1 is the time the B photon was detected by O' and the arrival of the time the B photon was emitted by B and recorded by b in the moving frame.
2 is the time the A and B photon arrived simultaneously at M and recorded by a|b in the moving frame, passengers sitting there when the train passed by M.
3 the time the A photon detected by O'. and the time of arrival of the recorded time the A photon was emitted at A - recorded by a.

From this Einstein tells us that the passengers using the train as an inertial frame "must, therefore come to the conclusion" that the photons emitted simultaneously in the stationary frame were not emitted simultaneously in the moving frame. This conclusion comes from the staggered arrival time of the B, then the A photon as detected by the moving observer O', period.

It is clear enough even before we begin that the the B photon will be detected first as the observer O' is moving toward the oncoming B photon and away from the A photon catching up from behind. Duh.

Taking Einstein at his word, and with a little incisive logic we can infer, as did Einstein, that the mere staggered detection of the B and A photons is the reason the passengers "must" conclude the photons were not emitted simultaneously in the moving frame. Or, in other words, as a corollary, observers observing the simultaneous arrival of the A and B photon in the moving frame will conclude the photons were emitted simultaneously in the moving frame.

1 The first flaw: The train is lengthy and observers at A and B in the moving frame a and b each record the emission time of the simultaneously emitted photons from A and B. The clocks in the moving frame are synchronized within the moving frame. Therefore when the a and b data are scrutinized by O' after the arrival of the final A photon she will see the a and b observers recorded the first simultaneous emission of the A and B emitted photons.

2. The second flaw: Observers on the moving frame a|b at t2, at M when the A and B photons arrive there simultaneously (after the B photon was detected by O') record the simultaneous arrival of the A and B photons at M. Here is the second detection of simultaneous arrival of photons in the moving frame.

3. From symmetry we can determine that t3, the time of detection of the A photon by O' can be expressed as t3 = t1(C + v)/(C - v). As t3 and t1 are measured moving frame values and as v is known, t3 can be checked. t3 is measured and if the photons were emitted simultaneously in the moving frame the calculated right hand side will agree with the measured left hand t3 value.

These are just three contradictions of the Einstein conclusion that the passengers "must" conclude the photons were not emitted simultaneously in the moving frame. Virtually all the passengers are able to determine the photons were emitted simultaneously in the moving frame.

Einstein did not use any postulates of light propagation other than the speed of light is a measured constant value of c = 3 x 10^8 m/sec. For this reason we could have used NASCARS with v = 300km/hr for the photons and a 1979 Ford Fairlane with v = 100 km/hr as the moving frame.

From the loss of simultaneity we discard absolute time, insert time dilation, insert contraction of physical length, and the ever constant measurement of the speed of light in all inertial frames (using time dilaltion and contraction of physical length, of course, in order to arrive at the constant measurement of c). From SR we are told we can "consider" physical impossibilities with abandon. Space ships moving with relative velocities of .0001c and .9999c can each consider themsleves at rest and the other ship moving. Each clock on the respective ships will show time dilation and each will consider the others clocks as slower than his own, and each will be correct as per SR that is. Train stations move and trains stand still, physical impossibilities , but mathematical junk. There is more but the story is much too sad to be told in one setting.
We get the postulates of Special Relativity based on the conclusion that passengers must conclude the photons were not emitted simultaneously in the moving frame. A tremendous burden for such a naively defined characteristic, isn't it?

From Einstein's definition of simultaneity as described in "Relativity": Events simultaneous in a stationary freame are not simultaneous in a moving frame." This a bogus definition and is the very heart and soul of special relativity. If the definition goes, so too special relativity.

This is not a definition of simultaneity, and Einstein did not define the word since its meaning is obvious. He simply stated that simultaneity is frame variant, which is not the heart and soul of special relativity, but rather a consequence of the two postulates.


It is clear enough even before we begin that the the B photon will be detected first as the observer O' is moving toward the oncoming B photon and away from the A photon catching up from behind. Duh.


The problem with this claim is that no frame of reference is specified. The statement that "O' is moving toward the oncoming B photon and away from the A photon" is true in the embankment's frame, but not in O's frame. According to O', O' is stationary and not moving toward or away from either photon.

Two common missteps when analyzing thought experiments like this one are:

1) Subconsciously working from the "stationary" (the ground) frame of reference without specifying it explicitly.

2) Assuming that the frame of the light source is the "correct" frame for the light itself. In other words, assuming that since O' is moving with respect to the light sources, then O's view of the light itself must be invalid.

I think that if you avoid these two problems, then your objections to relativity will disappear.

"Events simultaneous in a stationary freame are not simultaneous in a moving frame. This a bogus definition and is the very heart and soul of special relativity. If the definition goes, so too special relativity."

I still don't see why this should be bogus; just because it does not seem to be that way at slow velocities, it doesn't mean it's not true at high velocities.

"Events simultaneous in a stationary freame are not simultaneous in a moving frame. This a bogus definition and is the very heart and soul of special relativity. If the definition goes, so too special relativity."

I still don't see why this should be bogus; just because it does not seem to be that way at slow velocities, it doesn't mean it's not true at high velocities.
One reason i called it bogus is because of how he used the definition to explain the sequential arrival of photons to show a confirmation of what he had just defined.

No, because there is a flaw in your reasoning: time does not speed up to keep the speed of light constant. If you look at it properly, you can say that it is actually the other way around. If you were to look at another, moving observer, his time slows down with respect to yours because of the constancy of the speed of light (there is an important difference in cause and effect here). That other observer himself would not see something strange btw, for him it would appear as if time were ticking normally.

This effect (time dilatation) is independent of the direction of motion, and depends only on the speed of the observer. If it puzzles you, do a search for "time dilatation" on this forum and you'll find many, many threads on it (but beware, also many, many misinterpretations of it).
The reason light is always measued as C is from the moving observer putting herself at v = 0, therefore c is a guaranteed answer, with time diltion, frame contraction, and all the rest.

As light has not exhibited any anisotropic properties from all angles wrt to the planet earth the orb qualifies as a righteous preferred frame for v=0. Taking measurements wrt to the zero frame for all frames the relative velocity of all frames can be univesally determined.

I prefer the earth as a body of reference, a coordinate frame.

[QUOTE=hyperdog]It makes no sense to say that an observer is moving toward or away from light, since light has no unique frame of reference associated with it. With respect to what is the observer moving?/quote]

So to what is light measured then?

If a train of wavelengths of light is incident on my eye then as the wave lengths pass I have a way to count the number of waves per second and deternning how long it takes one wave to pass I calculate frequency.

And, by the way James, when we move toward that rock, how do we increase its
kinetic energy? Don't we have to change the relative velocity between us and the
rock?
2inquisitive, what if you were really at rest and the rock you thought you were heading for was really moving at you?

In any event take the case of all the light experiments easured from planet earth where the motion of the light has never exhibited any anisotropic properties, meaning one always measures C as the speed for light wrt the earth frame. The direction vector is changing at a rate of some 10^-8 radians per second. The difference in velocity is 4 orders of magnitude proportionally removed. Measure the speed of light wrt planet earth, then take the relative velocity of a frame wrt the earth and subtract these terms. Every thing taken wrt the earth an inertial frame and you get a righteous SR supported relative velocity. And look where we are, right in the middle of it all, just like the olden days, take a look up, well maybe.

It is the SR theorists that gave us Mother Earth as a reference frame, a zero velocity reference frame, and for personal reasons I prefer the earth frame as my body of reference. I wonder what eveilm plots they are scheming to unleash upon us, who only seek peace with our body of reference, our coordinate frame, yes our universal frame and our frame of preference.
SR made the error of the century, relatively speaking when they assumed that because frame earth gave a relative velocity of C that all frames, even those not at rest would be slaved to perform the same way. This is what you get when you go away for the weekend and someone gives a box of chalk to the mathematicians. Didn't those fools know what they were doing?

I am starting to choke in pity for the poor and lonely disinfranchiosed SRists, now idle minded and cast upon the tempest boiling sea, without boat nor oar, but I'm sure somene gave them a compass.

Rhetoric is one thing, geistkiesel. Substance is another.

If only you had something which supported your assertion...
The earth is an effective Velicty zero body of reference. This works for light and material as no experiment has resulted in light exhibting any nonisotropic proerties.

Rhetoric is one thing, geistkiesel. Substance is another.
I quote yopu your own words. tell me the the physics of assuming all inertial frames need necessarily consider measuring the velocityu of light C wrt to any inertial frame?

Rather than repeat myself in two different threads, I will restrict my responses to a single thread, namely, this one:

http://www.sciforums.com/showthread.php?t=38582

2inquisitive:



That is a purely relativistic effect. The observed decrease in wavelength is due to the relative speed between the observer and the wave - i.e. relativistic length contraction. The effect is insignificant in cases where the speed of the observer relative to the wave is much less than the speed of light.

Wrong, relativity has no effect. The apparent wave length shortening is an optical illusion inferred byu erroneous SR theory and assumptions. Of measureing the number of full wavelengths that pass the eye when moving against the velovcity fo the photons means only that the frequency of the count increases. There is not shortening of the wavelength, excep theoretically. The observer is not the body of reference of the photon and therefore the mere counting wavelengths/sec will not shorten the wavelength. Your assumption that speed controls the frame contraction and speed dilates time is not consitent with your statement here, and it is even inconsistent with SR.

This is an embarrassung contradivciton in your statement that the speed of the observer dilates time when measuring the frequency, yet when measuring the speed of light, the frame velocity is then set to zero. Oh yes the convenience of mathematics. I do not know how this goes James R can you help out a bit here?

The relevant equation is:

c = fL,

where f is the frequency of the light, L is the wavelength and c is the speed.

The theory of relativity is based on two postulates:

1. The laws of physics are form-invariant in all inertial reference frames.
2. The speed of light is constant for all observers, regardless of their state of motion.

The speed of light is constant and independent of the motion of the source of that light. But measuring the velocity of light Vl = C wrt to an earth frame assumed to have a velocity Ve = 0, does not mean that for moving frames wih Vf > 0 wrt the earth frame = 0, that the laws of physics dictate that all frames must also find the relative velocity = to the speed of light.

Open the eyes everybody and take a good long look at reality.

If ducks are measured with a velocity Vd in body of reference frame1 and measured relaive to frame2 as Vd2, then the relaive velocity iof the duck is not the same in all inertial frames. You are mistaking laws if physics with result from observation , by your making the concepts equivalent.

Big bad enmbarrassing mistake following in the footsteps of some publicity addicts that have been dead for better part of half a century - like an obedient band of robotic faithfulls.

Mac, I do not now, and have not in the past, believe the speed of light is invariant
TO THE OBSERVER. It is invariant from its source, only. That is why I do not personally
support any theory that depends on the speed of light relative to the observer as constant.
That is why I support Grounded's explanation and believe it to be true. Mac, you do
realize General Relativity is not dependent on the invariance of the speed of light,
don't you? You just always say 'relativity', but SR and GR are two different beasts.

I agree with what you say 2inquisitive, but the invariance discussed in SR theory, at least as expressed by AE, is that the relative velocities are the same for all observers. I believe the speed is the same, but SR theory effectively zeros the frame velocity to insure the finding that the relative velocity is = 0.

A Duck in flight wrt frame1 with Vd - Vf1 > d1 and another frame2 with Vd - Vf2 = d2 and not equal to Vf1, then Vf1 - Vf2 > d1 -d2. The relative velocity of ducks is handled OK by SR but why do they have a different physics for light? Go figure.

The mathematical addition of velocities in SR works exactly the same for light as for anything else. Your claim that light is handled differently is incorrect.

The mathematical addition of velocities in SR works exactly the same for light as for anything else. Your claim that light is handled differently is incorrect.
You mean that light is not measured other than C wrt any inertial frame?

I was looking for someplace to post this question and since this thread is quite developed ill try here...

In special relativity it is my understanding that an observer measuring the velocity of llight will always come stumble upon the same answer because when the observer is approaching the light, time must slow down because C≠ 299,792,458 m/s - V. If the observer were to instead of walking toward the light, back pedal and again try to measure the velocity of the light will time indeed speed up?
because surely C≠ 299,792,458 m/s + V

No, not for special relativitites. Because the frame velocity, your walking speeds are always considered zero whjen you measure the sol, ergo you always get C./. In other words, SR does not use the relative velocity of frame and photon as something to determine..

James R:

Have I got this wrong, or have you deleted my post within this thread regarding MY very relevant *wave analogy* thread?

http://www.sciforums.com/showthread.php?t=33377

If so, I though this was very applicable and closely linked to the discussions in this thread, so can you explain why you've deleted it?

Other peoples links to threads don't get deleted!

You mean that light is not measured other than C wrt any inertial frame?
No, he means that when you are doing addition of velocities, it is the same formula that you use for light or anything else.

dav57:

I've looked at the thread you linked to. I have not deleted any of your posts there. In fact, I can't remember ever deleting any of your posts at all. If I did so, I would certainly have left a message explaining why the post was deleted.

dav57:

I've looked at the thread you linked to. I have not deleted any of your posts there. In fact, I can't remember ever deleting any of your posts at all. If I did so, I would certainly have left a message explaining why the post was deleted.

Oh, ok, maybe I'm going daft! But I could have sworn that I had a post within this thread pointing to the WAVE ANALOGY thread. I know that Pete replied saying that it was very relevant to this topic. Just ignore me then, I'm having a bad day :(