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Are laws of nature really the same in all reference frames?

by Bjarne
Tags: frames, laws, nature, reference
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JordanL
#19
Sep27-11, 03:29 AM
P: 42
All this example shows is that the same measurement if we attempt it from different reference frames will yield different results, which is rather the point of them, isn't it? Distances, speeds and times are not absolute, they are relative... which is why it is called relativity. You cannot say the distance is shorter, because that has no meaning. It only appears so from particular reference frames.
Bjarne
#20
Sep27-11, 03:33 AM
P: 344
Quote Quote by JordanL View Post
All this example shows is that the same measurement if we attempt it from different reference frames will yield different results, which is rather the point of them, isn't it? Distances, speeds and times are not absolute, they are relative... which is why it is called relativity. You cannot say the distance is shorter, because that has no meaning. It only appears so from particular reference frames.

You can say that distance (for exsample near the Sun) mathematical and logical must be relative shorter, than for example here.
zonde
#21
Sep27-11, 06:13 AM
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Quote Quote by Bjarne View Post
It is not enough to say this is wrong, I must know why it should be wrong.
  • Is the time rate on Mercury, - the way a clock would count it, - only an illusion ?
  • Is speed seen from a Mercury perspective different?
  • Is Mass seen from a Mercury perspective not the same as on Earth
  • Or WHAT , - if not distance ?
It should be that G is numerically different.
G is global constant. And if it is global constant then locally it should be different at different gravitational potentials due to time dilation.
Or maybe it is more reasonable to find out if it's GM product that's different or not and then talk about G and M separately.

Gravitational time dilation should be real effect as you can observe it in static setup.
I suppose that observations are consistent with distances being the same.

Anyways question seems quite interesting.

EDIT: Ah, but certainly speed is different from Mercury perspective due to time dilation. So the question is if it is enough to make picture consistent.
zonde
#22
Sep27-11, 06:22 AM
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Quote Quote by A.T. View Post
No, this not equivalent. You can go anywhere and perform a local experiment in an inertial frame there, and then you get the same results. That is what "physical laws are the same globally" means.
If you perform Cavendish experiment at different gravitational potentials will it give the same results?
Hmm, only it is performed in non-inertial frame as almost all of the physics experiments. Then maybe discussion about inertial reference frames is not very useful?
ghwellsjr
#23
Sep27-11, 03:33 PM
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Quote Quote by Bjarne View Post
We did not got to the point. I mean we have a missing link here.
Let us forget everything about SR and only consider the consequence of GR and hence time dilation caused by gravity for 2 observers orbiting the MilkyWay.
OK, will do.
Quote Quote by Bjarne View Post
These 2 observers, one on the Earth and one on Mercury measure the orbit of the Sun round the Milkyway, by multiplying time and speed.

Now...
The observer on Earth will claim 1 orbit of the MilkyWay took exactly 1,19E16 Earth-second.
But the observer on Mercury would say that the orbit toke 194,000,000 s (6 earth-year) less according to his clock.

This time difference is only caused by GR...


Time dilation on Mercury relative to the Earth = 0,000000016 s. ( due to GR)
Time per year = 60*60*24*365 = 31,153,000 s.
Orbit of the MW = 314,000 Light Years (at the periphery).
Earth-Time to orbit the MW (250 km/s) = 377,000,000 years. (at the periphery).
Total Earth-second to 1 MW orbit = 377,000,000 * 365*24*60*60 = 1,19E16 seconds.
Lost" of Mercury-time in years = 1,19E16 s. * 0,000000016 s. = 194,000,000 s.

So after 1 MikyWay orbit the clock on Mercury have "lost" 194,000,000 seconds ( = 6 earth-years) relative to a clock on the Earth.

Now here is the simple question.
Is the circumference of the Milkyway the same for these 2 observers, so long we only speak about the mentioned time dilation due to GR ?
No.
Quote Quote by Bjarne View Post
If the answer is yes, - how is this possible when the rate of time not is the same ?

This only can mean a mathematical meltdown, right ?
The answer was no, so these don't need to be answered.
Quote Quote by Bjarne View Post
I mean since speed multiplied with the time one orbit takes must result to = Distances.

The only possible outcome I can see is that distance not can be the same, - so how can the law of gravity / the equations (and G) be the same?
They're not.
Quote Quote by Bjarne View Post
I don’t understand why it is necessary to complicate that simple question - more as necessary, - .

Distances cannot be the same so far I can understand this simple logic , - this is to me the only logical answer, - and this must mean G have a problem.

It is not enough to say this is wrong, I must know why it should be wrong.
  • Is the time rate on Mercury, - the way a clock would count it, - only an illusion ?
  • No.
    Quote Quote by Bjarne View Post
  • Is speed seen from a Mercury perspective different?
  • Yes.
    Quote Quote by Bjarne View Post
  • Is Mass seen from a Mercury perspective not the same as on Earth
  • It's not the same.
    Quote Quote by Bjarne View Post
  • Or WHAT , - if not distance ?
  • Everything is different.
Bjarne
#24
Sep28-11, 01:18 AM
P: 344
Bjarne
Is speed seen from a Mercury perspective different??
Ghwellsjr
Yes
Bjarne
So when we measure the speed of the Sun to travel 250 km/s, - an observer on Mercury (or on the surface of the Sun) would measure it to be a little more than this? - is this what you saying ? If so Why ?

Now imaging the same 2 observers measure the speed of a photon, we on Earth would measure it to be; “c” - would an observer on Mercury also measure that to be faster?

Can the speed difference, - significant or almost completely solve the "mathematical meltdown" described above, - or is this value almost irrelevant in this context?

Does the speed difference, - have anything to do with the cause of the the "mathematical meltdown" described above ?

Bjarne
Is Mass seen from a Mercury perspective not the same as on Earth
Ghwellsjr
It's not the same.
Bjarne
I mean is let’s say the mass of the Sun is exactly 2E30 Kg.
Are you saying an observer on Mercury not would agree ?
If so, - why?
What about the mass of the Milkyway? - would the 2 observers also disagree ?

Can the mass difference significant contribute to solve the "mathematical meltdown" described above, - or is it almost irrelevant in this context?

Does the mass difference, - have anything to do with the cause of the the "mathematical meltdown" described above ?

Ghwellsjr
Everything is different
What more as (time) speed and mass is different ?
zonde
#25
Sep28-11, 03:57 AM
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Let's try to put it down in less chaotic way.

As two observers observe the same sequence of physical events the only thing they can change is their representation of this sequence i.e. coordinate system.
Relative time dilation between two observers is real as we can establish delay in sequence of signals with static distance. So first of all we have different scale for time dimension for two observers.
Distances should be the same as speed of light locally is changing in a way that is consistent with unchanging distances.
Result of this is that orbital speed around MW for observer on Mercury is faster by the same factor as time is delayed.

Now we calculate GM-product μ using the same formula for both observers.
[tex]v_m^2=\frac{\mu_m}{r}[/tex]
[tex]v_e^2=\frac{\mu_e}{r}[/tex]
As speed is faster for Mercury observer but distances are the same for both observers we have that GM-product is bigger by that speed scaling factor squared. As GM-product have dimensions of time squared in denominator it seems that we have consistent picture so far.

Now if we assume that G is the same for both observers then mass unit for Mercury observer should be smaller by speed scaling factor squared.
This seems plausible as lowering mass in gravitational potential should convert part of the rest mass into kinetic energy.

Does this reasoning seems fine?
Bjarne
#26
Sep28-11, 01:50 PM
P: 344
Quote Quote by zonde View Post
Let's try to put it down in less chaotic way.

As two observers observe the same sequence of physical events the only thing they can change is their representation of this sequence i.e. coordinate system.
Relative time dilation between two observers is real as we can establish delay in sequence of signals with static distance. So first of all we have different scale for time dimension for two observers.
Distances should be the same as speed of light locally is changing in a way that is consistent with unchanging distances.
Result of this is that orbital speed around MW for observer on Mercury is faster by the same factor as time is delayed.

Now we calculate GM-product μ using the same formula for both observers.
[tex]v_m^2=\frac{\mu_m}{r}[/tex]
[tex]v_e^2=\frac{\mu_e}{r}[/tex]
As speed is faster for Mercury observer but distances are the same for both observers we have that GM-product is bigger by that speed scaling factor squared. As GM-product have dimensions of time squared in denominator it seems that we have consistent picture so far.

Now if we assume that G is the same for both observers then mass unit for Mercury observer should be smaller by speed scaling factor squared.
This seems plausible as lowering mass in gravitational potential should convert part of the rest mass into kinetic energy.

Does this reasoning seems fine?
I have not fine-read the last post (I have not much time yet), but the first that strike me is;
  • How can our Sun move with 2 different speed? - Something must be wrong.
  • The next is that; even if it did, “what would be causing that” ?
  • It would also mean that the 2 observer not could agree about the strength of gravity of the Milkyway.
Remember the point is only; the motion of the Sun , - and how two different space-time observers can agree about that.
ghwellsjr
#27
Sep28-11, 03:31 PM
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Quote Quote by Bjarne View Post
Bjarne
So when we measure the speed of the Sun to travel 250 km/s, - an observer on Mercury (or on the surface of the Sun) would measure it to be a little more than this? - is this what you saying ? If so Why ?
Someone on the surface of another planet with a different mass than Earth could measure it a little or a lot more or less than ours because their rulers are different lengths than we would if they're based on the same standards that ours are based on and this is because of your stipulation:
Quote Quote by Bjarne View Post
Let us forget everything about SR and only consider the consequence of GR and hence time dilation caused by gravity for 2 observers orbiting the MilkyWay.
Quote Quote by Bjarne View Post
Now imaging the same 2 observers measure the speed of a photon, we on Earth would measure it to be; “c” - would an observer on Mercury also measure that to be faster?
No, everyone measures the speed of light to be "c".
Quote Quote by Bjarne View Post
Can the speed difference, - significant or almost completely solve the "mathematical meltdown" described above, - or is this value almost irrelevant in this context?

Does the speed difference, - have anything to do with the cause of the the "mathematical meltdown" described above ?
I thought your issue about a mathematical meltdown would only apply if I answered "yes" to your previous question but since I answered "no", I don't know what you mean by a mathematical meltdown and again, everyone measures the speed of light to be exactly the same value "c" so there's no mathematical meltdown that I can see.
Quote Quote by Bjarne View Post

Bjarne
I mean is let’s say the mass of the Sun is exactly 2E30 Kg.
Are you saying an observer on Mercury not would agree ?
If so, - why?
Yes, he would say the sun had a different mass because all his measuring devices are different due to the difference in gravity between the Earth and Mercury.
Quote Quote by Bjarne View Post
What about the mass of the Milkyway? - would the 2 observers also disagree ?
Yes, they would disagree about everything.
Quote Quote by Bjarne View Post
Can the mass difference significant contribute to solve the "mathematical meltdown" described above, - or is it almost irrelevant in this context?

Does the mass difference, - have anything to do with the cause of the the "mathematical meltdown" described above ?
You're going to have to explain to me what this mathematical meltdown is. I didn't know such a thing could be possible.
Quote Quote by Bjarne View Post
What more as (time) speed and mass is different ?
Everything measureable and observable is different:
Temperatures
Colors
Ages
Sizes
Shapes
Frequencies
Pressures
Forces
Directions
I'm having a hard time trying to think of something that wouldn't be put on the list.
Bjarne
#28
Sep28-11, 04:16 PM
P: 344
Quote Quote by ghwellsjr View Post
You're going to have to explain to me what this mathematical meltdown is. I didn't know such a thing could be possible.
.
Let's simplify the scenario
Ignore that the observers are orbiting different planet with different mass.
And ignore the influence of SR

Let's say the 2 clocks are orbiting the Sun without the planets Mercury and the Earth.
One clock (A) 50 billion km away and the other (B) 150 km away.
So the problem and the calculation shown above are still the same.

Both observers would see the Sun complete 1 orbit of the Milkyway at the same time.
But observer A would have "lost" 194,000,000 s. relative to B

If the orbit speed of the Sun = 250 km/s -for both observers / clocks, - observer A would calculate a shorter orbit of he Sun than B would - That would violate the laws of gravity.

If the speed not was the same for both – (first I must ask WHY should it not ?)
That would also violate the laws of gravity.
And it would rise the question; how can the Sun move with 2 different speed ?

So WHY can these 2 observers impossible agree about which measurement of the orbit of the Sun is the correct one?
Passionflower
#29
Sep28-11, 04:49 PM
P: 1,555
Quote Quote by ghwellsjr View Post
their rulers are different lengths than we would if they're based on the same standards that ours are based on and this is because of your stipulation:
...
No, everyone measures the speed of light to be "c".
You seem to be making a lot of definite statements, could you back them up?

Perhaps you would like to explain a bit more by what you mean, for instance our meter is defined by the speed of light, however you claim the speed of light is everywhere the same even in locations with a different gravitational potential. But you at the same time claim that rulers are different lengths.
JordanL
#30
Sep28-11, 05:01 PM
P: 42
Quote Quote by Bjarne View Post
Let's simplify the scenario
Ignore that the observers are orbiting different planet with different mass.
And ignore the influence of SR

Let's say the 2 clocks are orbiting the Sun without the planets Mercury and the Earth.
One clock (A) 50 billion km away and the other (B) 150 km away.
So the problem and the calculation shown above are still the same.

Both observers would see the Sun complete 1 orbit of the Milkyway at the same time.
But observer A would have "lost" 194,000,000 s. relative to B

If the orbit speed of the Sun = 250 km/s -for both observers / clocks, - observer A would calculate a shorter orbit of he Sun than B would - That would violate the laws of gravity.

If the speed not was the same for both – (first I must ask WHY should it not ?)
That would also violate the laws of gravity.
And it would rise the question; how can the Sun move with 2 different speed ?

So WHY can these 2 observers impossible agree about which measurement of the orbit of the Sun is the correct one?
Speed is a measure of distance over time. As both distance AND time are different in the two frames, the speed is different as well. (Also, a minor point, but I believe you mean velocity. Speed is different from velocity in physics.)
ghwellsjr
#31
Sep28-11, 05:35 PM
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Quote Quote by Bjarne View Post
Let's simplify the scenario
Ignore that the observers are orbiting different planet with different mass.
And ignore the influence of SR

Let's say the 2 clocks are orbiting the Sun without the planets Mercury and the Earth.
One clock (A) 50 billion km away and the other (B) 150 km away.
So the problem and the calculation shown above are still the same.
Still the same? From the beginning of this thread, you have been talking about observers on the surface of solar system planets (non-inertial) and so I wondered how you could think orbiting at different distances from the sun (inertial) could be the same. That prompted me to go back and look at your post #18 and now I understand what's going on here.

I'm afraid I have made a big mistake. When I was getting ready to study your post #18, I went to the Thread Tools and used the "Show Printable Version" to print out your thread. The printable version did not print your graphic but instead showed the URL from which it was taken. So I go to www.science27.com and I see that you are promoting your own personal theory in violation of the forum rules.

Bye, bye.
zonde
#32
Sep28-11, 11:08 PM
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P: 1,376
Quote Quote by Bjarne View Post
I have not fine-read the last post (I have not much time yet), but the first that strike me is;

How can our Sun move with 2 different speed? - Something must be wrong.
Of course our Sun can't move at two different orbital speeds. But our measurements of that speed can be different.

First sentence in my explanation was:
"As two observers observe the same sequence of physical events the only thing they can change is their representation of this sequence i.e. coordinate system."
If you would use two clocks that tick at different speeds then with the same measuring rods your speed measurements will be different.

Quote Quote by Bjarne View Post
The next is that; even if it did, “what would be causing that” ?
It would also mean that the 2 observer not could agree about the strength of gravity of the Milkyway.


Remember the point is only; the motion of the Sun , - and how two different space-time observers can agree about that.
Bjarne
#33
Sep29-11, 01:28 AM
P: 344
Quote Quote by ghwellsjr View Post
Still the same? From the beginning of this thread, you have been talking about observers on the surface of solar system planets (non-inertial) and so I wondered how you could think orbiting at different distances from the sun (inertial) could be the same. That prompted me to go back and look at your post #18 and now I understand what's going on here.

I'm afraid I have made a big mistake. When I was getting ready to study your post #18, I went to the Thread Tools and used the "Show Printable Version" to print out your thread. The printable version did not print your graphic but instead showed the URL from which it was taken. So I go to www.science27.com and I see that you are promoting your own personal theory in violation of the forum rules.

Bye, bye.

I am NOT promoting my own personal theory in one single word.
I am using my own webhotel to load graphics, and as you self wrote it was accidentally that you at all discovered that I had personally websites / theory.
It sounds to me that you say; that only people that not have a personally theory are allowed to ask (skeptical) questions to science, - at this forum.

I asked the question because I want to understand nature, as well as I want to understand my own theory.
Is that really "forbidden" ?

When "my thought" that something must be obvious wrong, with the way different observers understand the orbits (speed/distance) of the sun , - you had have the change to lead me back to the right track, and you still have. But I am afraid such track even not exist. But I am not sure.
Bjarne
#34
Sep29-11, 01:49 AM
P: 344
Quote Quote by zonde View Post
Of course our Sun can't move at two different orbital speeds. But our measurements of that speed can be different.

First sentence in my explanation was:
"As two observers observe the same sequence of physical events the only thing they can change is their representation of this sequence i.e. coordinate system."
If you would use two clocks that tick at different speeds then with the same measuring rods your speed measurements will be different.
First at all I want to say that we can simplify the scenario even more, to avoid confusion.

Because we could say that the 2 clocks are following the Sun’s orbit around the Milkyway.
(Technical we could say the orbiting clocks have devices (small rockets) on board to counteract the gravity from the Sun.

Seen from our perspective both the Sun and the two clocks (all 3 objects) are therefore orbiting the Milkyway in the excact same radius to the center of the Milkyway) .

The one clock is 50 billion km. behind the Sun, and the other 150 billion km.

This should eliminate he last confusion according to the Special relativity influence, since all relative speed now are the same.

Back to yours suggestion;
As I understand you now I can only understand it like that speed not is comparable “the same” – which then also mean that also comparable distances not can be the same, - right?

I think we have a serious mathematical problem here and wonder how such a simple obviously unsolved mystery possible can have existed the last 100 years without any explanation. ?

I mean the math should be simple.
We know the 2 relative time rates and I believe we also know the speed, - the logical result (so far I can understand it) hence should be that B impossible can travels the same distance, simple because speed multiplied with time = distance.

I mean how difficult can that really be ?
zonde
#35
Sep29-11, 06:43 AM
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P: 1,376
Quote Quote by Bjarne View Post
First at all I want to say that we can simplify the scenario even more, to avoid confusion.

Because we could say that the 2 clocks are following the Sun’s orbit around the Milkyway.
(Technical we could say the orbiting clocks have devices (small rockets) on board to counteract the gravity from the Sun.

Seen from our perspective both the Sun and the two clocks (all 3 objects) are therefore orbiting the Milkyway in the excact same radius to the center of the Milkyway) .

The one clock is 50 billion km. behind the Sun, and the other 150 billion km.

This should eliminate he last confusion according to the Special relativity influence, since all relative speed now are the same.

Back to yours suggestion;
As I understand you now I can only understand it like that speed not is comparable “the same” – which then also mean that also comparable distances not can be the same, - right?

I think we have a serious mathematical problem here and wonder how such a simple obviously unsolved mystery possible can have existed the last 100 years without any explanation. ?

I mean the math should be simple.
We know the 2 relative time rates and I believe we also know the speed
We don't know the speed. We measure speed i.e we make some observations and then come up with some number.
Two observers will come up with different numbers from their respective observations. Just because these numbers are different doesn't mean that they live in different worlds. It just means that they use different units for their measurements. In particular case it is time unit that is different.

Quote Quote by Bjarne View Post
- the logical result (so far I can understand it) hence should be that B impossible can travels the same distance, simple because speed multiplied with time = distance.

I mean how difficult can that really be ?
Bjarne
#36
Sep29-11, 02:51 PM
P: 344
Quote Quote by zonde View Post
We don't know the speed. We measure speed i.e we make some observations and then come up with some number.
Two observers will come up with different numbers from their respective observations. Just because these numbers are different doesn't mean that they live in different worlds. It just means that they use different units for their measurements. In particular case it is time unit that is different.
If speed is different for the 2 observers, - classic laws of gravity would not (as I see it) be the same. - I mean how could these?

Or the gravity of the galaxy would not be the same for the 2 observers. That too would sound absurd.

What should possible cause two different speed, or different influence of gravity?


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