Einstein's clock

[Aqueous Id]

The rotational acceleration makes no difference

(1.) Orbital acceleration of the earth is causes dilation, so yes, it makes a difference.

because it only applies when the frames are again at the same place.

(2.) Dilation due to SR accretes continuously throughout the earth's orbit.

It's too small to explain anything.

(3.) It's just the right size to account for dilation.

So, we have a y direction location light sphere location which is exactly the same for both frames

(4.) No, they would not agree, by a small dilation, on where the wavefront is.

and a different clocks measurement.

(5.) Yes, a small difference.

Therefore, we do not have a constant speed of light

(6.) No, that's wrong, probably due to your error in (4).

if you are correct.

(7.) You mean if spacetime is correct.

 

[Aqueous Id]

In short, this problem proves one cannot have a constant speed of light c and time dilation.

Both cannot be true.

No, it just proves you made an error.

 

[chinglu]

For what?
If you could explain "the experiment" clearly, and show how all the experiments that have been done to verify relativity are a contradiction, you might be on to something.Your thought experiment isn't very well thought?

1) There is an observer stationary with the sun on the orbital path of earth.
2) There is an observer on the earth.
3) When the earth observer and the other observer are common, a light pulse is emitted from their common location.
4) After 1 year (or so) the two are again at the same place.
5) The earth observer's clock is time dilated.
6) The two observer's measure the distance from their common location on any axis perpendicular (say y axis) the earth's motion to the light sphere. This eliminates length contraction.
7) Since they must measure different times since the light pulse was emitted, then either they measure a different speed of light or they measure a different position of the light sphere from their common location.

Either way, relativity does not hold true.

 

[chinglu]

(1.) Orbital acceleration of the earth is causes dilation, so yes, it makes a difference.


(2.) Dilation due to SR accretes continuously throughout the earth's orbit.


(3.) It's just the right size to account for dilation.


(4.) No, they would not agree, by a small dilation, on where the wavefront is.


(5.) Yes, a small difference.


(6.) No, that's wrong, probably due to your error in (4).


(7.) You mean if spacetime is correct.

If you can demonstrate a calculation in GPS for the acceleration of a satellite relative to the earth's center, then your argument makes sense.

But, because GPS only uses a gravity differential, Sagnac and time dilation, then your argument is invalid.

Since the two observers are at the same place when the measurement takes place, that eliminates a gravity differential and also sagnac. All that is left is the traditional SR time dilation.

Now, since they are measuring from the same place on a line perpendicular to the earth's travel eliminating length contraction, then the y units are the same for both observers.

Also, since the earthbound clock is time dilated, then either the speed of light is not a constant or one light sphere must be located in the y direction at two different places, both of which force a contradiction in relativity.

 

[arfa brane]

1) There is an observer stationary with the sun on the orbital path of earth.
2) There is an observer on the earth.
3) When the earth observer and the other observer are common, a light pulse is emitted from their common location.

Let's look at 3) more closely. The only way both observers can be "common" is if they are in the same stationary frame (are not moving relative to each other).

4) After 1 year (or so) the two are again at the same place.
5) The earth observer's clock is time dilated.

5) is always true because of the relative motion, however.

6) The two observer's measure the distance from their common location on any axis perpendicular (say y axis) the earth's motion to the light sphere. This eliminates length contraction.

Please prove that length contraction is "eliminated", instead of simply claiming it.

7) Since they must measure different times since the light pulse was emitted, then either they measure a different speed of light or they measure a different position of the light sphere from their common location.[

Either way, relativity does not hold true.

They measure different times because they have clocks running at at different rates. The different positions are because of Lorentz contraction. So relativity isn't violated. So your conclusion doesn't follow, and your thought experiment still isn't very well defined.
Why isn't the observer who is stationary in the sun frame, affected by the earth's gravity? How do both observers synchronise clocks properly? Maybe leave out the earth and just have one observer stationary to, the other orbiting, the sun? That is, assume the gravitational interaction between the observers can be ignored?

 

[AlexG]

4) After 1 year (or so) the two are again at the same place.

But the moving observer is still moving, and the stationary observer is still stationary.

6) The two observer's measure the distance from their common location on any axis perpendicular (say y axis) the earth's motion to the light sphere. This eliminates length contraction.

First of all, how do you propose to measure the distance. Second, why do you assume they will measure the same distance? Remember, observer 1 is moving, relative to observer 2. The fact that they occupy the same coordinate at a given moment of time doesn't mean they occupy the same frame of reference.

 

[chinglu]

Let's look at 3) more closely. The only way both observers can be "common" is if they are in the same stationary frame (are not moving relative to each other).
5) is always true because of the relative motion, however.Please prove that length contraction is "eliminated", instead of simply claiming it.They measure different times because they have clocks running at at different rates. The different positions are because of Lorentz contraction. So relativity isn't violated. So your conclusion doesn't follow, and your thought experiment still isn't very well defined.
Why isn't the observer who is stationary in the sun frame, affected by the earth's gravity? How do both observers synchronise clocks properly? Maybe leave out the earth and just have one observer stationary to, the other orbiting, the sun? That is, assume the gravitational interaction between the observers can be ignored?

1) Both observers common means they are at the same place. Here is Einstein with 2 different frames.

At the time t = t' = 0, when the origin of the co-ordinates is common to the two systems, let a spherical wave be emitted therefrom,
http://www.fourmilab.ch/etexts/einstein/specrel/www/

2) When both observers are at the same place a 2nd time, they must conclude the same gravity at that location or one location give two different gravity readings.

3) Einstein claimed in the above that at the time the origins are common, the clocks can be synched at that location. Take that up with him.

 

[chinglu]

But the moving observer is still moving, and the stationary observer is still stationary.



First of all, how do you propose to measure the distance. Second, why do you assume they will measure the same distance? Remember, observer 1 is moving, relative to observer 2. The fact that they occupy the same coordinate at a given moment of time doesn't mean they occupy the same frame of reference.

1) It does not matter who is moving.

2) Any measurement in the perpendicular direction of motion has the same units for both frames. That is relativity. You need to research that.

 

[brucep]

1) There is an observer stationary with the sun on the orbital path of earth.
2) There is an observer on the earth.
3) When the earth observer and the other observer are common, a light pulse is emitted from their common location.
4) After 1 year (or so) the two are again at the same place.
5) The earth observer's clock is time dilated.
6) The two observer's measure the distance from their common location on any axis perpendicular (say y axis) the earth's motion to the light sphere. This eliminates length contraction.
7) Since they must measure different times since the light pulse was emitted, then either they measure a different speed of light or they measure a different position of the light sphere from their common location.

Either way, relativity does not hold true.

Get a clue.

The difference between the total tick rates between wristwatch times of the two observers is difficult to measure since IT"S SO SMALL. But I'll calculate it for you.

In geometric units

Set
dt_1 = observer 1 at rest on r_shell = 1 tick

r_shell = mean radius of Earths natural path [orbit] around the Sun = 1.495978E11 meter.

M_sun = 1477 meter

dTau_2 = observer 2 stationed on the Earth as it follows its natural path.

v_earth orbit = (M_sun/r_shell)^1/2 = 9.936360826E-5

The ratio

dTau_2/dt_1 = (1-v^2)^1/2 = .999999995

When they meet up and compare clocks they measure a total dt = .155768s with the traveling clock of observer 2 ticking 5E-9 slower per second.

That's not remotely the 'worst thing' for your experiment. The thing about the observers getting different final measurements for a pulse of light, they were both present for, when it was emitted [a year ago?] won't fly. At each and every ~flat segment over each observers path they will measure the local coordinate speed of light to be invariant. So that means over the course of the experiment both observers always measured the local coordinate speed of light to be invariant. That includes before they split up, their entire path over the duration of the experiment, and when they meet up again. Wow that's exactly what relativity says.

 

[chinglu]

Get a clue.

The difference between the total tick rates between wristwatch times of the two observers is difficult to measure since IT"S SO SMALL. But I'll calculate it for you.

In geometric units

Set
dt_1 = observer 1 at rest on r_shell = 1 tick

r_shell = mean radius of Earths natural path [orbit] around the Sun = 1.495978E11 meter.

M_sun = 1477 meter

dTau_2 = observer 2 stationed on the Earth as it follows its natural path.

v_earth orbit = (M_sun/r_shell)^1/2 = 9.936360826E-5

The ratio

dTau_2/dt_1 = (1-v^2)^1/2 = .999999995

When they meet up and compare clocks they measure a total dt = .155768s with the traveling clock of observer 2 ticking 5E-9 slower per second.

That's not remotely the 'worst thing' for your experiment. The thing about the observers getting different final measurements for a pulse of light, they were both present for, when it was emitted [a year ago?] won't fly. At each and every ~flat segment over each observers path they will measure the local coordinate speed of light to be invariant. So that means over the course of the experiment both observers always measured the local coordinate speed of light to be invariant. That includes before they split up, their entire path over the duration of the experiment, and when they meet up again. Wow that's exactly what relativity says.

OK, so you agree the moving clock is time dilated.

However, this history of the measurements along the travel is irrelevant. It only matters the instantaneous measurement when the frames are again common.

Now, are you claiming they cannot measure a y-axis with identity units perpendicular to the line of travel?

Remember, relativity must survive instantaneous measurements. Are you claiming this is false?

 

[AlexG]

Remember, relativity must survive instantaneous measurements. Are you claiming this is false?

Where do you get this idea from?

 

[chinglu]

Where do you get this idea from?

I got it from Einstein. This is an instantaneous measurement.

At the time t' = t = 0, when the origin of the co-ordinates is common to the two systems, let a spherical wave be emitted therefrom
http://www.fourmilab.ch/etexts/einstein/specrel/www/

 

[Aqueous Id]

If you can demonstrate a calculation in GPS for the acceleration of a satellite relative to the earth's center, then your argument makes sense.

The sats are preloaded with a 7.2 μsec/day correction for this.

But, because GPS only uses a gravity differential, Sagnac and time dilation, then your argument is invalid.

What argument? And what time dilation are you referring to?

Since the two observers are at the same place when the measurement takes place, that eliminates a gravity differential and also sagnac. All that is left is the traditional SR time dilation.

No, they are in separate reference frames at all times.

Now, since they are measuring from the same place on a line perpendicular to the earth's travel eliminating length contraction, then the y units are the same for both observers.

No, it's not the same place, because they are in separate reference frames.

Also, since the earthbound clock is time dilated, then either the speed of light is not a constant or one light sphere must be located in the y direction at two different places, both of which force a contradiction in relativity.

No, you are still missing the point that they are separate reference frames. There's no such thing as "a single place" and "a single time". Nothing is violated. You're just wrong about what relativity says, how it works, and the way it's exhibited in nature.

 

[arfa brane]

I got it from Einstein. This is an instantaneous measurement.

At the time t' = t = 0, when the origin of the co-ordinates is common to the two systems, let a spherical wave be emitted therefrom
http://www.fourmilab.ch/etexts/einstein/specrel/www/

That's NOT an "instantaneous" measurement. Einstein says quite clearly: "let a spherical wave be emitted", from the common origin. This is an instantaneous event, measurement is something else, and is observer-dependent, which is what he's trying to show, you dingbat.

 

[arfa brane]

Another detail which Einstein kind of ignores, is that synchronisation is not instantaneous. Clocks are physical so adjusting them isn't an instantaneous process. However, you can assume that a clock can be built that it takes a very small amount of time to adjust.

And if two observers are colocated, as long as they remain stationary wrt each other it doesn't matter how long it takes for them to synchronise. The important part is that they (eventually) have synchronous clocks. But this changes completely when observers are in relative motion, since "instantaneous" is different for both observers.
Which is why relativity deals necessarily with different kinds of time--proper time, coordinate time, etc.

 

[chinglu]

That's NOT an "instantaneous" measurement. Einstein says quite clearly: "let a spherical wave be emitted", from the common origin. This is an instantaneous event, measurement is something else, and is observer-dependent, which is what he's trying to show, you dingbat.

Does your brain now claim all of physics cannot measure instantaneous measurements?

LOL

Prove your assertions.

 

[chinglu]

The sats are preloaded with a 7.2 μsec/day correction for this.

What argument? And what time dilation are you referring to?


No, they are in separate reference frames at all times.


No, it's not the same place, because they are in separate reference frames.


No, you are still missing the point that they are separate reference frames. There's no such thing as "a single place" and "a single time". Nothing is violated. You're just wrong about what relativity says, how it works, and the way it's exhibited in nature.

What is the problem with measuring the y axis location of the light sphere when the observers are again at the same place?

 

[chinglu]

Another detail which Einstein kind of ignores, is that synchronisation is not instantaneous. Clocks are physical so adjusting them isn't an instantaneous process. However, you can assume that a clock can be built that it takes a very small amount of time to adjust.

And if two observers are colocated, as long as they remain stationary wrt each other it doesn't matter how long it takes for them to synchronise. The important part is that they (eventually) have synchronous clocks. But this changes completely when observers are in relative motion, since "instantaneous" is different for both observers.
Which is why relativity deals necessarily with different kinds of time--proper time, coordinate time, etc.

Who cares.

When they return to the same place the moving clock is time dilated.

Yet, the also have a common y axis for the location of the light sphere.

Thus, we have a contradiction.

 

[arfa brane]

Does your brain now claim all of physics cannot measure instantaneous measurements?

Does yours understand that Einstein isn't referring to measurement when he says "At the time t' = τ = 0, when the origin of the co-ordinates is common to the two systems, let a spherical wave be emitted therefrom".

He's talking about an event which is simultaneous to the origin, i.e. when the origin of both systems of coordinates is common. But one system is moving relative to the other, so the two systems will measure different things.

But by all means, clingτo your misinτerpreτaτion, chinglu.

 

[Aqueous Id]

What is the problem with measuring the y axis location of the light sphere when the observers are again at the same place?

The earth never stops accelerating.