Constancy of SOL from all objects

[michel123456]

 

 

 

You might notice that nothing you quoted says that the photon stops. That's you.

As observed by the earth?

Or do you mean as if there was an absolute state of motion? (sarcastic again)

 

-----------------

BTW you may notice that a new notion has been introduced following which the photons have another speed depending on the state of the observer.

Edited July 27, 2016 by michel123456

[Mordred]

Well thats a silly notion. You already have length contraction and time dilation with c being invarient to all observers.

Now you wish to introduce another dimension of change?

If you think about it. Your last statement essentially reads.

 

"We must observe light during its entire passage in order to have a definable velocity."

 

if the speed of light is dictated by observers. How would light travel without any observers.????

 

You seem to have a misunderstanding of GR. Time dilation and contraction does occur without any observers.

 

Google muon decay with regards to Earths atmosphere for example. Those muons will still strike the Earths surface regardless of observers. They can only do so with time dilation.

Edited July 27, 2016 by Mordred

[michel123456]

Well thats a silly notion. You already have length contraction and time dilation with c being invarient to all observers.

Now you wish to introduce another dimension of change?

If you think about it. Your last statement essentially reads.

 

"We must observe light during its entire passage in order to have a definable velocity."

 

if the speed of light is dictated by observers. How would light travel without any observers.????

 

You seem to have a misunderstanding of GR. Time dilation and contraction does occur without any observers.

 

Google muon decay with regards to Earths atmosphere for example. Those muons will still strike the Earths surface regardless of observers. They can only do so with time dilation.

You are speaking of 2 different things.

1. the speed of light: we call light whatever travels at c. This definition is exactly what GR is telling us: SOL does not depend on the source, SOL depends on the observer. I like to compare it to a kind of horizon. It is our observational limit.

2. the phenomenon of light: of course lots of phenomena are occuring without any need to be observed. I guess even phenomena that remain unknown.

Edited July 28, 2016 by michel123456

[swansont]

You are speaking of 2 different things.

1. the speed of light: we call light whatever travels at c. This definition is exactly what GR is telling us: SOL does not depend on the source, SOL depends on the observer. I like to compare it to a kind of horizon. It is our observational limit.

 

How do you know which one is moving?

As observed by the earth?

Or do you mean as if there was an absolute state of motion? (sarcastic again)

Find me the part where that article says "the photon stops"

 

BTW you may notice that a new notion has been introduced following which the photons have another speed depending on the state of the observer.

It's not a new notion that non-inertial frames will observe light to move at a speed different than c

[Strange]

1. the speed of light: we call light whatever travels at c. This definition is exactly what GR is telling us

 

This is what SR tells us, not GR.

 

 

This definition is exactly what GR is telling us: SOL does not depend on the source, SOL depends on the observer. I like to compare it to a kind of horizon.

 

What GR tells us is that the (coordinate, or apparent) speed of light depends on the relationship between the source and the observer. (That is why it is the theory of "relativity".)

 

The proper speed of light is, of course, always c.

[michel123456]

 

This is what SR tells us, not GR.

 

 

What GR tells us is that the (coordinate, or apparent) speed of light depends on the relationship between the source and the observer. (That is why it is the theory of "relativity".)

 

The proper speed of light is, of course, always c.

It is wrong. You admitted before that Relativity is a theory of observation. The world does not expands or shrink because of the observer. What happens is that the observer gets a deformed image of the world. There is no "relationship". The Speed of light depends on nothing. It is invariant. Because it is invariant we see the things we see, not the reverse.

[Strange]

It is wrong. You admitted before that Relativity is a theory of observation. The world does not expands or shrink because of the observer. What happens is that the observer gets a deformed image of the world. There is no "relationship". The Speed of light depends on nothing. It is invariant. Because it is invariant we see the things we see, not the reverse.

 

Of course it is about the relationship. If you observe photons from a clock in a higher gravitational potential then they will be red-shifted and the clock will run slower. If you observe photons from a clock in a lower gravitational potential then they will be blue-shifted and the clock will run faster.

 

If it was just about the observer, that wouldn't be the case.

[imatfaal]

It is wrong. You admitted before that Relativity is a theory of observation. The world does not expands or shrink because of the observer. What happens is that the observer gets a deformed image of the world. There is no "relationship". The Speed of light depends on nothing. It is invariant. Because it is invariant we see the things we see, not the reverse.

 

Not sure quite what you are getting at but it sounds as if you are claiming that everything is merely in the eye of the beholder. This is not the case - length contraction and time dilation are real phenomena not an artefact of observation. In the LHC we take lead ions and speed them up - the ion streams smash into each other at fantastic speeds. We then compare the results to the models we have drawn up regarding such energetic collisions - to get results that are even close to the hot quark gluon plasma which we observe we must model the ions as discs highly flattened in the direction of travel.

 

There is also the muon decay observation that was mentioned earlier in which the reciprocity of time dilation (from our perspective) and length contraction (from the muons 'perspective') are complementary over the two frames to show how muons with a short life time can travel much further than we would expect

[swansont]

It is wrong. You admitted before that Relativity is a theory of observation. The world does not expands or shrink because of the observer. What happens is that the observer gets a deformed image of the world. There is no "relationship". The Speed of light depends on nothing. It is invariant. Because it is invariant we see the things we see, not the reverse.

Deformed implies that there is some inherent, correct undeformed view, and relativity tells us there isn't. I will view something as being a meter at length because I am at rest with respect to ti. You see it as being 0.8 meters because you are moving with respect to it. It does not shrink or expand, and your view is not deformed. That is simply how long the object is, according to your frame.

 

Of course it is about the relationship. If you observe photons from a clock in a higher gravitational potential then they will be red-shifted and the clock will run slower. If you observe photons from a clock in a lower gravitational potential then they will be blue-shifted and the clock will run faster.

 

If it was just about the observer, that wouldn't be the case.

 

It might be helpful to use larger and smaller when quantifying, because a lower (smaller magnitude) gravitational potential is higher in the well, and that can lead to confusion.

[michel123456]

Deformed implies that there is some inherent, correct undeformed view, and relativity tells us there isn't. I will view something as being a meter at length because I am at rest with respect to ti. You see it as being 0.8 meters because you are moving with respect to it. It does not shrink or expand, and your view is not deformed. That is simply how long the object is, according to your frame.

 

It might be helpful to use larger and smaller when quantifying, because a lower (smaller magnitude) gravitational potential is higher in the well, and that can lead to confusion.

Yes I agree, it does not shrink or expand. It is like it is according to your frame.

 

It is not a theory that says how are things, it is a theory that says how one will observe the world according to his frame. It counts also for the way we are observing muons.

 

Not sure quite what you are getting at but it sounds as if you are claiming that everything is merely in the eye of the beholder. This is not the case - length contraction and time dilation are real phenomena not an artefact of observation. In the LHC we take lead ions and speed them up - the ion streams smash into each other at fantastic speeds. We then compare the results to the models we have drawn up regarding such energetic collisions - to get results that are even close to the hot quark gluon plasma which we observe we must model the ions as discs highly flattened in the direction of travel.

 

There is also the muon decay observation that was mentioned earlier in which the reciprocity of time dilation (from our perspective) and length contraction (from the muons 'perspective') are complementary over the two frames to show how muons with a short life time can travel much further than we would expect

If a theory describes accurately observation, you will be unable to escape. if the theory predicts that you will observe ions as discs flattened in the direction of travel then you must not be surprised to discover that it happens in your laboratory.

But it has been said repeatedly that if a spaceship is observed as length contracted from the Earth, the astronaut will feel no contraction at all. (he will see the Earth contracting). In this sense yes it is in the eye of the beholder.

Edited July 28, 2016 by michel123456

[Mordred]

no your still missing the big picture. Observers do affect how we measure. However time dilation and length contraction doesnt always involve observers. They occur regardless of the observer.

 

Where the observer comes into play is comparing the two inertial reference frames and showing the differences between the two frames.

 

For example an observer on the spacecraft you mentioned wont observe his craft as length contracted or time dilated because he is in the same frame of reference.

 

This doesnt mean that there is no time dilation or length contraction. In fact there is to another reference frame.

 

length contraction and time dilation doesn't depend on reference frames. The observer shows the differences between one reference frame compared to another reference frame.

 

This is an extremely important distinction

 

Relativity can be described as measurement change between reference frames. Or from one reference frame to another.

Edited July 28, 2016 by Mordred

[michel123456]

no your still missing the big picture. Observers do affect how we measure. However time dilation and length contraction doesnt always involve observers. They occur regardless of the observer.

 

Where the observer comes into play is comparing the two inertial reference frames and showing the differences between the two frames.

 

For example an observer on the spacecraft you mentioned wont observe his craft as length contracted or time dilated because he is in the same frame of reference.

 

This doesnt mean that there is no time dilation or length contraction. In fact there is to another reference frame.

 

length contraction and time dilation doesn't depend on reference frames. The observer shows the differences between one reference frame compared to another reference frame.

 

This is an extremely important distinction

 

Relativity can be described as measurement change between reference frames. Or from one reference frame to another.

Dear Mordred with all my respect I think you are confused this time. Or at least you are confusing me. Half of your arguments i agree with but you use them to say the contrary.

[swansont]

Yes I agree, it does not shrink or expand. It is like it is according to your frame.

 

It is not a theory that says how are things, it is a theory that says how one will observe the world according to his frame. It counts also for the way we are observing muons.

 

 

But one thing they agree on is that light travels at c, regardless of the source, because they are in inertial frames.

 

If you do not have an inertial frame, then that isn't true.

[Mordred]

Dear Mordred with all my respect I think you are confused this time. Or at least you are confusing me. Half of your arguments i agree with but you use them to say the contrary.

Its not really that hard to figure out. The problem seems to stem from the fact that GR describes the differences between reference frames.

 

You place a clock in an inertial frame that clock will run at a specific rate regardless of whether or not someone is observing the clock.

If you compare the inertial clock to a clock at rest you find a difference in clock rates. Thats when observer comes into effect. THE Comparison between the two clocks.

 

 

Ok lets try a redshift comparison. Simply because its easier to relate to than time dilation...

 

Our sun emits a specific blackbody temperature. That will give a specific wavelength. Different inertial observers will measure different wavelengths. However those observers Cannot and do not change the temperature of the Sun itself.

 

The redshift is the difference between actual temperature vs observed temperature.

 

Same thing with time dilation. Changing the observer doesnt change the proper time of the object. It just changes the amount of difference between the proper time of the object compared to the proper time of the observer.

 

Consider this You are observer A looking at your wrist watch. You always see your wrist watch running at a constant rate.

 

A different observer in a different reference frame will observe a different rate compared to his wrist watch.

 

No matter what Observer B does (speed up or slow down) The rate that observer A sees his wrist watch moving doesnt change.

 

Both observers will disagree that the wrist watch shows a constant time. Yet both observations are equally accurate. If observer B takes time dilation into effect and calculates the differences due to time dilation. Then both observers agree that the wrist watch is running at a constant rate and the difference between clocks is due to the difference between reference frames (relativity)

Edited July 28, 2016 by Mordred

[michel123456]

Its not really that hard to figure out. The problem seems to stem from the fact that GR describes the differences between reference frames.

 

You place a clock in an inertial frame that clock will run at a specific rate regardless of whether or not someone is observing the clock.

If you compare the inertial clock to a clock at rest you find a difference in clock rates. Thats when observer comes into effect. THE Comparison between the two clocks.

 

 

Ok lets try a redshift comparison. Simply because its easier to relate to than time dilation...

 

Our sun emits a specific blackbody temperature. That will give a specific wavelength. Different inertial observers will measure different wavelengths. However those observers Cannot and do not change the temperature of the Sun itself.

 

The redshift is the difference between actual temperature vs observed temperature.

 

Same thing with time dilation. Changing the observer doesnt change the proper time of the object. It just changes the amount of difference between the proper time of the object compared to the proper time of the observer.

 

Consider this You are observer A looking at your wrist watch. You always see your wrist watch running at a constant rate.

 

A different observer in a different reference frame will observe a different rate compared to his wrist watch.

 

No matter what Observer B does (speed up or slow down) The rate that observer A sees his wrist watch moving doesnt change.

 

Both observers will disagree that the wrist watch shows a constant time. Yet both observations are equally accurate. If observer B takes time dilation into effect and calculates the differences due to time dilation. Then both observers agree that the wrist watch is running at a constant rate and the difference between clocks is due to the difference between reference frames (relativity)

So?

what is your conclusion of all this?

 

That the wrist watch is time dilated because some observer somewhere in the Universe is measuring it from a different frame?

Or that the guy with the wrist watch is really length contracted for the same reason?

Because time dilation & length contraction are supposed to truly happen? This is nonsense. If there are ten observers in 10 different frames, how is the watch time dilated? Or length contracted?

Edited July 28, 2016 by michel123456

[StringJunky]

So?

what is your conclusion of all this?

 

That the wrist watch is time dilated because some observer somewhere in the Universe is measuring it from a different frame?

Or that the guy with the wrist watch is really length contracted for the same reason?

Because time dilation & length contraction are supposed to truly happen? This is nonsense. If there are ten observers in 10 different frames, how is the watch time dilated? Or length contracted?

All frames are correct because there is no absolute frame. Are you saying that the Hafele-Keating experiment is wrong or the adjustments made in the GPS clocks are wrong? That time dilation doesn't truly happen?

[Mordred]

So?

what is your conclusion of all this?

 

That the wrist watch is time dilated because some observer somewhere in the Universe is measuring it from a different frame?

Or that the guy with the wrist watch is really length contracted for the same reason?

Because time dilation & length contraction are supposed to truly happen? This is nonsense. If there are ten observers in 10 different frames, how is the watch time dilated? Or length contracted?

Time dilation and length contraction are both occuring regardless of observer.

 

You might think this is ridiculous but science has essentailly proven this.

 

We certainly didnt sit beside the clock on Mount Everest watching each second tick by. Yet without any observer. That clock ticked at a different rate than a clock at a different reference frame.

 

 

That time dilation DID NOT REQUIRE an observer to occur

 

That is your misconception of what is meant by the term relativity.

[michel123456]

Time dilation and length contraction are both occuring regardless of observer.

 

You might think this is ridiculous but science has essentailly proven this.

 

We certainly didnt sit beside the clock on Mount Everest watching each second tick by. Yet without any observer. That clock ticked at a different rate than a clock at a different reference frame.

 

 

That time dilation DID NOT REQUIRE an observer to occur

 

That is your misconception of what is meant by the term relativity.

You haven't answer my questions.

All frames are correct because there is no absolute frame. Are you saying that the Hafele-Keating experiment is wrong or the adjustments made in the GPS clocks are wrong? That time dilation doesn't truly happen?

You have been contaminated.

 

How many length contractions do truly happen when there are 10 different observers in 10 different frames?

[Mordred]

10 (Assuming they are measuring the same object. If not then 10^10 length contractions possible roughly.)change the proper length. They change the coordinate length.

 

No observer changes the proper time in a reference frame. Each observer in your scenario has his own proper time.

Edited July 28, 2016 by Mordred

[StringJunky]

You haven't answer my questions.

You have been contaminated.

 

How many length contractions do truly happen when there are 10 different observers in 10 different frames?

They are all correct in their frames. The accuracy of SR is exquisite; no other word for it.

 

10 but none change the proper length. They change the coordinate length

Can you dumb that down for me; the difference?

[Strange]

You have been contaminated.

 

[Mordred]

They are all correct in their frames. The accuracy of SR is exquisite; no other word for it.

 

Can you dumb that down for me; the difference?

Actually I got proper time and coordinate time backwards. Those two always trip me up lol. Coodinate time is the event itself. Ie observer and emitter. each being a seperate event.

 

Proper time is the time along the light path worldline.

 

What Im trying to get through to Michel is each reference frame has in actuality its own rate of time. That doesnt depend on observers.

 

https://en.m.wikipedia.org/wiki/Proper_time

Edited July 28, 2016 by Mordred

[michel123456]

Actually I got proper time and coordinate time backwards. Those two always trip me up lol. Coodinate time is the event itself. Ie observer and emitter. each being a seperate event.

 

Proper time is the time along the light path worldline.

 

What Im trying to get through to Michel is each reference frame has in actuality its own rate of time. That doesnt depend on observers.

 

https://en.m.wikipedia.org/wiki/Proper_time

You did it again. One sentence says white, the other says black.

 

AND

there cannot be 10 "real" different length contractions for a single object. Each observer measures a different length contraction, that's all.

and if you go next to the measured object and join the same frame, you will measure no contraction at all.

[StringJunky]

What Im trying to get through to Michel is each reference frame has in actuality its own rate of time. That doesnt depend on observers.

Yeah, it's not hard to understand; it only takes a few years to sink in. I think he is considering his own frame as the sole reference frame and all the others are an illusion. It's also made more difficult because which part of your body is in the position with the correct time: your head stomach or feet?

[swansont]

 

AND

there cannot be 10 "real" different length contractions for a single object. Each observer measures a different length contraction, that's all.

and if you go next to the measured object and join the same frame, you will measure no contraction at all.

 

 

We just went through this. There is no "real" to be had here. It implies one frame is "truth". There is no underlying reality to be had. if you measure the meter stick to be 0.8 meters, then that's how long it is, as measured in your frame. "How long is it, really?" is a nonsensical question; it has no answer.