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

In summary: Earth the photon would have traveled 600,000 km!In summary, both A and B would agree that the stone falls 10 meter in one Earth second, but B would only see that the stone falls 5 meter when time is measured on Mercury. Both observers use the same laws of gravity, but because time and distance are not the same for A and B, the laws of gravity must be adjusted all the time.
  • #1
Bjarne
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Let’ say; “A” can see and measure a stone falls to the Earth let’s say 10 meter per 1 Earth-second.
“B” lives at Mercury and can see the same thing.
But “B” would do not see the exactly the same, because seen from “B’s” viewpoint time / distance is not the same as for “A”.
Let us say time at Mercury would tick half so fast compared to a clock at the Earth.

B would not agree it took the stone 1 second to move 10 meter – but have seen that the stone only was moving ½ -mercury second.
B will therefore also not see the stone falling 10 meter (as A saw it was falling in one Earth-second), but only that the stones was falling 5 Mercury-meter.

It must matter whether the stone was falling 10 meter (from A’s viewpoint) in a certain period, - or only 5 meter (B’s viewpoint), - So the problem is now, how can all laws of nature be the same for all observers.

If distances not are changing proportional the same rate as time, - A and B would not agree of the speed of light. Hence distance always must change proportional with time, right?.

Both A and B would therefore observe the “same” speed of the stone, - even though a process on Mercury would take relative double so long time measured with a Earth-clock.

It is simple math to understand that the speed of the stones anyway “seems” to be the “same” for both of A+B, - but in fact it is not, simply because time is different, and distance too.

For example if we on Earth (A) see a photon traveling from the Moon to the Earth, and it take 1 second, - the same event (according to the example) would seen from Mercury only take ½ second.
But because distance seen from the Mercury viewpoint (between the Moon and the Earth) is only the half compared to the Earth viewpoint, - a photon would hence after one Mercury-second have traveled the double distance meassured 1 second, - with a Earth-clock.
Which mean that after 1 Mercury second the photon must have traveled 600,000 Earth-km measured in 2 second with a Earth clock. (Since 2 Mercury-second = 1 Earth-seconds)

Let’s return to the real world to make that more clear.
After 1 orbit of the Milkyway, a clock at Mercury (B) would REALLY have “lost” 6 years compared to a clock at the Earth (A).

The point is that when time/distance not is the same for A and B, how can the laws expressed by Newtonian and Keplerian equations be the same everywhere.

At least the gravity constant “G” seems to must be adjusted all the time, since distance is changing all the time.
Otherwise the result of gravity will not be right by our feeds compared to ours noses.
How can a person that not share ours time-distances share (our) gravity constant (G) ?

For example;
A person living at mercury and another at the Earth could never agree about the distance - our Sun - travels the MilkyWay, - simple because time is not the same these two places.
Evidence is atomic clock wouldn’t lie on these two planets.

When 2 such observers cannot agree about distances /radius/ diameter of the Milkyway, - how is it possible for both to use the excact same gravity equations ?

If we exaggerate and say that a clock on Mercury ticks half so fast as on Earth, - this would mean that after 1 orbit of the Milkyway we on Earth have travels 377,000 Light years, but a person living at Mercury would say the orbit only is the half.

Therefore 2 such observers must also get two different result of how strong gravity of the Milky way really is ?

How can we then say that the laws of Newtonian/Keperian gravity are the same for both observers?
 
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  • #2
When we say the same laws apply, we're talking about formulas but the numbers we plug into those formulas and the results can be
different on each planet, except everone will measure the same value for the speed of light.
 
  • #3
The Point is that the gravity constant "G" cannot be the same, at different planets (etc), even not the same by your feed as by your nose, since time and distance not are the same.

I you would live on Mercury you would also measure the "same" speed of every motion included light, but when you would compared such speeds, with how an observer on Earth would see the same event these are not the same speed because distances of Mercury are shorter.

For example according to the example mentioned above, - after 1 Mercury-second the photon must have traveled 300,000 Mercury-km - but at the same time (period) it have travel 600,000 Earth-km
This is because 2 second measurement with a Earth clock is 1 Mercury-second measurement with a Mercury clock .

The observer on Mercury would hence say 600,000 Earth km is only 300,000 Mercury-km, and therefore in fact the photon must REALLY be moving double so far measured with a Earth-Meter stick compared to a Mercury meter-stick. ( but still the "same" speed/ distance seen from the perspective of both observers (without comparing).

This must mean that the observer plays the "primary role", - the Universe plays a secondary role.
Or that; - the Universe is like the eyes (clocks) see it, and not opposite.
 
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  • #4
You are right, the gravity constant, "g", is not the same on different planets, it's not even a constant on Earth but changes slightly from location to location due to differences in the mass density of the Earth at different locations and due to changes in elevation, but the gravitational constant, "G", does not change due to any local considerations. I would suggest you look up the articles in wikipedia on these two "constants" if you want to learn about them. But these issues have nothing to do with different laws at these different locations.

You have expressed concerns about the effects of gravity on measurements which is a very complex subject and requires an understanding of General Relativity. I would suggest that you focus first on understanding Special Relativity because that is so much easier and I think that once you can see how different observers traveling with respect to each other (no gravity involved) can both measure the speed of light to be the same, even though they each measure the other one's clocks and rulers to be different than their own. That, after all, is what this forum is for, understanding relativity. Are you interested in learning and understanding Special Relativity?

In the meantime, I'd like you to think about your comment regarding seeing a photon traveling from the moon to the Earth and I would like to ask you, how can anyone see a photon? This has bearing on your last comment:

This must mean that the observer plays the "primary role", - the Universe plays a secondary role.
Or that; - the Universe is like the eyes (clocks) see it, and not opposite.​
 
  • #5
ghwellsjr said:
You are right, the gravity constant, "g", is not the same on different planets, it's not even a constant on Earth but changes slightly from location to location due to differences in the mass density of the Earth at different locations and due to changes in elevation,
"g" is not part of the question.

but the gravitational constant, "G", does not change due to any local considerations.
I geuss you would write that.

I would suggest you look up the articles in wikipedia on these two "constants" if you want to learn about them.
But these issues have nothing to do with different laws at these different locations.
The laws are the same, but but G can’t be, - it seems to mathematical impossible.

You have expressed concerns about the effects of gravity on measurements which is a very complex subject and requires an understanding of General Relativity.

I can't see why it should be "so complex"
The essence is 2 clocks are ticking differently, -; this is all we so fare need to know.
We have 2 clock and 2 different observers. One observer could be you, - the other a man and a clock on Mercury.
How long distance would the Sun travel seen from the perspective of these two observers (in 377,000 years / orbit the MW) - and which distance is the “right distance” ?.

After 1 orbit of the Milkyway (MW) these 2 observers could impossible agree about what the radius / diameter circumference or the MW is.
If time is different and speed of light must be the "same” for all observers - left is only that distances not can be the same.
It seems to me to be a simple mathematic necessity.
So why make this simple event more difficult as is possible can be?

I would suggest that you focus first on understanding Special Relativity because that is so much easier and I think that once you can see how different observers traveling with respect to each other (no gravity involved) can both measure the speed of light to be the same, even though they each measure the other one's clocks and rulers to be different than their own. That, after all, is what this forum is for, understanding relativity.

I believe I know a lot about it, - but still we only dealing with simple facts; - 2 observers/clocks ticking with different rate cannot agree how the distance is of the MW.

Doesn’t matter whether the reason to the different time rate is GR or SR, - distances cannot be the same, and hence the Keplerian and Newtonian laws of gravity , - yes are the same, - but G cannot be, - since distances is the main factor of gravity.

In the meantime, I'd like you to think about your comment regarding seeing a photon traveling from the moon to the Earth and I would like to ask you, how can anyone see a photon?

Don't take it literary..
The principle is what count.
When time not is the same distances can also not be, - and hence "G" can also not be.
On the one hand speed seems to be the same for both observer, - on the other hand, - so soon you compare how the distance difference (measured by 2 different relativistic observers) is , the observer with the slow clock must measure a shorter comparable distance, - in a certain period common for both.

So on the one hand, any observer will see (measure) light (a photon) travels 300,000 km/h, -but only because of distances not can be the same, - on the other hand that picture is wrong so soon you compare what have happen in a certain period.

I think we shall be carefully not to use relativity as a junkyard for things that not make sence, and allow export to such junkyard so soon something is “so complex” that probably nobody has understood it.

So fare I see this question, there MUST be a simple logical mathematical explanation, doesn’t, matter whether the clock ticks different due to gravity (GR) or fast motion (SR)..

“If you can't explain it simply, you don't understand it well enough”.
Albert Einstein
 
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  • #6
You have stated that you believe you know a lot about SR but yet you have said:
Bjarne said:
Hence distance always must change proportional with time, right?
But while time dilates (gets longer), length contracts (gets shorter) so it's not proportional, it's an inverse relationship. Furthermore, it's only distance in certain directions that is contracted. How do you explain this?
 
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  • #7
Bjarne,

Why not try approaching it with a simpler comparison. Have A and B initially together in the same inertial reference system (on earth, out in space away from everything..., you pick it), and each is furnished with a laboratory on separate identical space ships. They can perform any of the basic experiments historically used to describe our physical laws.

Now, they take off in opposite directions at relativistic speeds (it really doesn't matter whether they go at the same speeds relative to the original rest frame or not). Each one performs a number of different experiments and then return to their original rest frame to compare their results. Their results will be the same.

So, yes--the laws of physics are the same in all inertial reference frames.

Also, if you have them land on distant planets (ignoring the inhabitable environments) and perform experiments, they will come up with the same results such as Newton's law of gravitation; they will find that masses attract with a force inversely proportional to r^2 with the same Newton gravitation constant, G. They will both find F = ma. The ratio of e/m will be the same, etc.

They probably won't have any more luck with experiments aimed at unification of general relativity and quantum mechanics than anyone has had so far.
 
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  • #8
ghwellsjr said:
You have stated that you believe you know a lot about SR but yet you have said:

But while time dilates (gets longer), length contracts (gets shorter) so it's not proportional, it's an inverse relationship. Furthermore, it's only distance in certain directions that is contracted. How do you explain this?

Once again, there are no reasons to limit this question to Special Relativity.
The fact is that a clock on board on Mercury really is ticking slower as one at Earth.
Hence an observer (a clock) on Mercury must have "lost" 6 years due to GENERAL relativity, (compared to a clock at the Earth) after one MW orbit of the solar system.

This give you 2 simple possibilities

1.)
An observer on Mercury must have seen the Sun (orbit the MW) faster as an observer at the Earth have observed the same event (faster as the 250 km/s - the speed we on Earth observe the Solar system (the Sun) is orbiting the MW) - I don't believe you can sell that to anyone because that would in the end violate that “c” always is the same.

2.)
That distance is not the same for both observers. - This is logic math since an observer on Mercury would see the Sun complete 1 orbit of the MW in less time (6 years less) as seen from the Earth.
 
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  • #9
Bjarne said:
Once again, there are no reasons to limit this question to Special Relativity.
The title of your thread is "Are laws of nature really the same in all reference frames?". You are referring to Einstein's first postulate for Special Relativity and it is true only for inertial reference frames. It is not true in accelerating frames which is what you have on the surface of planets and which is handled by General Relativity.

You have stated:
Bjarne said:
Doesn’t matter whether the reason to the different time rate is GR or SR,

...doesn’t, matter whether the clock ticks different due to gravity (GR) or fast motion (SR)..
But it does matter because in SR, time dilation is reciprocal and in GR it is not. It's only the reference frames in SR where the laws of nature are the same. Under the influence of different gravity fields, the laws are different. To put it another way: a scientist inside a box in any inertial frame cannot determine which kind of an inertial frame he is in, they are all the same due to the reciprocal nature of time dilation (among other things). But if you put him in an accelerating box, or in a box on the surface of a planet, he will be able to tell the difference between the boxes because they can have different accelerations and the time dilation is not reciprocal between two boxes on different planets (or on the same planet at different elevations).
 
  • #10
ghwellsjr said:
Under the influence of different gravity fields, the laws are different.
It's not that they are different, but rather that in GR inertial frames don't extend infinitely. So in GR the equivalence of inertial frames only applies to local experiments.
 
  • #11
A.T. said:
It's not that they are different, but rather that in GR inertial frames don't extend infinitely. So in GR the equivalence of inertial frames only applies to local experiments.
Under relativity inertial frames are constructed so that physical laws stay the same.

Now you say that inertial frames are not extendable globally. To me this statement seems equivalent to the statement that physical laws are not the same globally.
 
  • #12
A.T. said:
It's not that they are different, but rather that in GR inertial frames don't extend infinitely. So in GR the equivalence of inertial frames only applies to local experiments.
I thought I made it very clear in my post that I was addressing the non-inertial frames on the surfaces of planets which is what Bjarne is using in his argument against Einstein's first postulate of Special Relativity. How does your post help Bjarne?
 
  • #13
zonde said:
Under relativity inertial frames are constructed so that physical laws stay the same.
You've got it backwards: Under relativity, physical laws are constructed so that they stay the same in different inertial frames, if they are not already that way.
 
  • #14
ghwellsjr said:
The title of your thread is "Are laws of nature really the same in all reference frames?".
You are referring to Einstein's first postulate for Special Relativity and it is true only for inertial reference frames.
It is not true in accelerating frames which is what you have on the surface of planets and which is handled by General Relativity.

Now you confuse me.
My concern is mainly if ALL laws of nature (equations) ALWAYS the same for all observer.
OR is (for example) gravity - and here I mean G (the gravity constant) an exception´.
Above you wrote; "G", does not change due to any local considerations"
I am now not sure what you really mean, - Is "G" ALWAY constant. - Yes or no ?


But it does matter because in SR, time dilation is reciprocal and in GR it is not. It's only the reference frames in SR where the laws of nature are the same. Under the influence of different gravity fields, the laws are different.
So is it true that G is not the same by your feed as by you nose ?
Yes of no ?
If the answer is no, then try to explain how 2 observers located in different space-time (caused by gravity) obviously not would be able to agree how long time one MW orbit take, - and therefore logical also not agree what the radius of the MW really is , - and therefore also not agree what G really is ? - What I mean is; - there are no common answers. G cannot be a constant - OR WHAT ?

To put it another way: a scientist inside a box in any inertial frame cannot determine which kind of an inertial frame he is in, they are all the same due to the reciprocal nature of time dilation (among other things). But if you put him in an accelerating box, or in a box on the surface of a planet, he will be able to tell the difference between the boxes because they can have different accelerations and the time dilation is not reciprocal between two boxes on different planets (or on the same planet at different elevations).
I prefer first to finish the easy part (the GR part) before confusion the discussion with SR.
So fare according to this context I believe a clock (observer) on Mercury don't care why time ticks slower, - exactly as we don’t care why our clock is slower as a clock on Neptune, I mean how much time dilation is due to GR and SR - the point will still be is G ALWAYS constant ?

Yes or no.
 
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  • #15
zonde said:
Now you say that inertial frames are not extendable globally.
Yes, not in curved space time.
zonde said:
To me this statement seems equivalent to the statement that physical laws are not the same globally.
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.
 
  • #16
A.T. said:
Yes, not in curved space time.

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.

In other words, globally there is local consistency, at the cost of locally there being global consistency?

EDIT:

Actually, consistency is the wrong word. What I suppose I meant was that globally there is local continuity of physical laws, instead of locally there being global continuity of physical laws. That's, as far as I understand it, rather the entire point of SR.
 
  • #17
Bjarne said:
Now you confuse me.
It's no wonder you are confused when you don't read my posts. Let me reiterate:
Bjarne said:
My concern is mainly if ALL laws of nature (equations) ALWAYS the same for all observer.
ghwellsjr said:
The title of your thread is "Are laws of nature really the same in all reference frames?". You are referring to Einstein's first postulate for Special Relativity and it is true only for inertial reference frames. It is not true in accelerating frames which is what you have on the surface of planets and which is handled by General Relativity.
Bjarne said:
OR is (for example) gravity - and here I mean G (the gravity constant) an exception´.
ghwellsjr said:
the gravity constant, "g"
...
the gravitational constant, "G"
Bjarne said:
Above you wrote; "G", does not change due to any local considerations"
I am now not sure what you really mean, - Is "G" ALWAY constant. - Yes or no ?
ghwellsjr said:
the gravitational constant, "G", does not change due to any local considerations.
Bjarne said:
So is it true that G is not the same by your feed as by you nose ?
Yes of no ?
ghwellsjr said:
the gravity constant, "g", is not the same on different planets, it's not even a constant on Earth but changes slightly from location to location due to differences in the mass density of the Earth at different locations and due to changes in elevation
Bjarne said:
If the answer is no, then try to explain how 2 observers located in different space-time (caused by gravity) obviously not would be able to agree how long time one MW orbit take, - and therefore logical also not agree what the radius of the MW really is , - and therefore also not agree what G really is ? - What I mean is; - there are no common answers. G cannot be a constant - OR WHAT ?
The effect of different gravity constants "g" on different planets will not cause scientists on those planets to arrive at different values of the gravitational constant "G". We have the same problem here on Earth where g varies but you have to take that into consideration when calculating constants that are independent of your local situation. The value of "G" is not dependent on any particular local circumstance.
Bjarne said:
I prefer first to finish the easy part (the GR part) before confusion the discussion with SR.
So fare according to this context I believe a clock (observer) on Mercury don't care why time ticks slower, - exactly as we don’t care why our clock is slower as a clock on Neptune, I mean how much time dilation is due to GR and SR - the point will still be is G ALWAYS constant ?

Yes or no.
I have said G is constant, g is not constant.

Is the reason that you think GR is easier than SR because things like time dilation and length contraction are not reciprocal?
 
  • #18
ghwellsjr said:
I have said G is constant,

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.

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...

[PLAIN]http://www.science27.com/forum/td2.jpg [Broken]
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 ?

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 ?

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?

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 ?
  • 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 ?
 
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  • #19
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.
 
  • #20
JordanL said:
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.
 
  • #21
Bjarne said:
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.
 
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  • #22
A.T. said:
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?
 
  • #23
Bjarne said:
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.
Bjarne said:
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...

[PLAIN]http://www.science27.com/forum/td2.jpg [Broken]
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.
Bjarne said:
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.
Bjarne said:
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.
Bjarne said:
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.
    Bjarne said:
    [*]Is speed seen from a Mercury perspective different?
    Yes.
    Bjarne said:
    [*]Is Mass seen from a Mercury perspective not the same as on Earth
    It's not the same.
    Bjarne said:
    [*]Or WHAT , - if not distance ?
    Everything is different.
 
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  • #24
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 ?
 
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  • #25
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?
 
  • #26
zonde said:
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.
 
  • #27
Bjarne said:
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:
Bjarne said:
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.
Bjarne said:
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".
Bjarne said:
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.
Bjarne said:
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.
Bjarne said:
What about the mass of the Milkyway? - would the 2 observers also disagree ?
Yes, they would disagree about everything.
Bjarne said:
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.
Bjarne said:
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.
 
  • #28
ghwellsjr said:
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?
 
  • #29
ghwellsjr said:
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.
 
  • #30
Bjarne said:
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.)
 
  • #31
Bjarne said:
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.
 
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  • #32
Bjarne said:
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.

Bjarne said:
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.
 
  • #33
ghwellsjr said:
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.
 
Last edited:
  • #34
zonde said:
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 ?
 
Last edited:
  • #35
Bjarne said:
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.

Bjarne said:
- 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 ?
 
<h2>1. What are laws of nature?</h2><p>Laws of nature are fundamental principles that describe the behavior and interactions of the physical world. They are based on observations and experiments and are used to explain and predict natural phenomena.</p><h2>2. How do laws of nature relate to reference frames?</h2><p>Reference frames are used to describe the position and motion of objects in space. Laws of nature are the same in all reference frames, meaning they apply universally regardless of the observer's perspective or frame of reference.</p><h2>3. What is the significance of laws of nature being the same in all reference frames?</h2><p>This means that the laws of nature are consistent and do not change based on the observer's perspective. It allows for the development of scientific theories and models that can accurately describe and predict natural phenomena.</p><h2>4. Are there any exceptions to the laws of nature being the same in all reference frames?</h2><p>There are certain situations, such as near the speed of light or in extreme gravitational fields, where the laws of nature may appear to behave differently. However, these exceptions can be explained by more complex theories, such as Einstein's theory of relativity, which still maintain the overall consistency of the laws of nature.</p><h2>5. How do scientists test the universality of laws of nature in different reference frames?</h2><p>Scientists use experiments and observations to test the laws of nature in different reference frames. They may also use mathematical models and simulations to predict and compare the behavior of natural phenomena in different frames of reference. These methods help to validate the universality of the laws of nature.</p>

1. What are laws of nature?

Laws of nature are fundamental principles that describe the behavior and interactions of the physical world. They are based on observations and experiments and are used to explain and predict natural phenomena.

2. How do laws of nature relate to reference frames?

Reference frames are used to describe the position and motion of objects in space. Laws of nature are the same in all reference frames, meaning they apply universally regardless of the observer's perspective or frame of reference.

3. What is the significance of laws of nature being the same in all reference frames?

This means that the laws of nature are consistent and do not change based on the observer's perspective. It allows for the development of scientific theories and models that can accurately describe and predict natural phenomena.

4. Are there any exceptions to the laws of nature being the same in all reference frames?

There are certain situations, such as near the speed of light or in extreme gravitational fields, where the laws of nature may appear to behave differently. However, these exceptions can be explained by more complex theories, such as Einstein's theory of relativity, which still maintain the overall consistency of the laws of nature.

5. How do scientists test the universality of laws of nature in different reference frames?

Scientists use experiments and observations to test the laws of nature in different reference frames. They may also use mathematical models and simulations to predict and compare the behavior of natural phenomena in different frames of reference. These methods help to validate the universality of the laws of nature.

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