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

by Bjarne
Tags: frames, laws, nature, reference
P: 344
 Quote by DaleSpam Again, how exactly do you plan on making the comparison?
I don't understand the question..
Time, and hence 1 second is not comparable the same in different space time, - do you not agree to that?
Mentor
P: 17,527
 Quote by Bjarne I don't understand the question.
I am asking for a detailed description of what experiment you are planning on doing in order to compare a 1 s on the ISS to 1 s on the earth, and how are you going to interpret different possible results of that experiment in terms of comparing the seconds?
P: 344
 Quote by DaleSpam I am asking for a detailed description of what experiment you are planning on doing in order to compare a 1 s on the ISS to 1 s on the earth, and how are you going to interpret different possible results of that experiment in terms of comparing the seconds?
I cannot see the problem.
Clocks ticks different in different space time.
Let us say you were living in a relative very strong gravitionel field, compared to me.
Let’s say it will take 2 second on my atomic clock, - to observer one second ticking on yours atomic clock.

Opposite it will take you ½ second to observe 1 second ticking on my atomic clock.

The definition of 1 second is for both of us 9,192,631,770 cesium frequency cycles per second.

But it will take a comparable long second (relative double period “of time”) for your clock to reach this number, and only a relative comparable short (½) period, and hence a short second for me to count the same numbers of frequencies.

So the comparable second is not the same. I cannot understand how you seem not to agree to that.
Mentor
P: 17,527
 Quote by Bjarne Clocks ticks different in different space time.
You are going in circles. I ask you how you are making the comparison and you simply assert that they are "different". Since "different" is a comparison where you find that they are not equal that still leaves the question of exactly how you are making the comparison.

Please answer the question. How are you comparing clock rates at different points in spacetime?

 Quote by Bjarne Let us say you were living in a relative very strong gravitionel field, compared to me. Let’s say it will take 2 second on my atomic clock, - to observer one second ticking on yours atomic clock.
What is the experiment you are proposing here? How do you "observer" the time ticking on your clock and mine?
P: 344
 Quote by DaleSpam You are going in circles. I ask you how you are making the comparison and you simply assert that they are "different". Since "different" is a comparison where you find that they are not equal that still leaves the question of exactly how you are making the comparison. Please answer the question. How are you comparing clock rates at different points in spacetime?
Satellites proves this every day

 What is the experiment you are proposing here? How do you "observer" the time ticking on your clock and mine?
I cannot see any other option, - can you ?
 PF Gold P: 4,087 Bjarne, your answers are getting more and more feeble. I think you misunderstand what is meant by "the laws of physics are the same in all inertial frames" so I'll spell it out. If an experiment is done in lab A to test the law f=ma using billiard ball type experiments and of course measuring with local clocks and rulers, then the result will be the same as in any other lab frame, where of course, they use their local clocks and rulers. It matters not a jot if the local clocks and rulers are 'different', both frames will verify that f=ma is true, up to a small experimental error. Going on about seconds or centimeters being different in different frames is irrelevant.
Mentor
P: 17,527
 Quote by Bjarne I cannot see any other option, - can you ?
Sure, I can see at least 4 ways to compare two distant clocks:

A) Broadcast a reference signal, measure the frequency of the signal locally at each clock
B) Take a reference clock, physically transport it from one clock to the other and measure the rate of the reference locally at each clock
C) Agree on a standard physics experiment as a reference, perform it locally at each clock and measure the time for the experiment
D) Agree on an astronomical reference, and measure the time for the astronomical reference locally

Your suggested measurement of one year with two clocks is an example of D. Your mention of satellites probably refers to A. Mentz114's recent post refers to C, which encapsulates the principle of relativity. I came up with B on my own.

With D and A you will get that the Earth clock and the ISS clock run at different rates. With B and C you will get that the Earth clock and the ISS clock run at the same rates.

The beauty of GR is that it is a single law of physics which explains A, B, C, and D all together.
 P: 344 Double .
P: 344
 Quote by DaleSpam Sure, I can see at least 4 ways to compare two distant clocks: A) Broadcast a reference signal, measure the frequency of the signal locally at each clock B) Take a reference clock, physically transport it from one clock to the other and measure the rate of the reference locally at each clock C) Agree on a standard physics experiment as a reference, perform it locally at each clock and measure the time for the experiment D) Agree on an astronomical reference, and measure the time for the astronomical reference locally Your suggested measurement of one year with two clocks is an example of D. Your mention of satellites probably refers to A. Mentz114's recent post refers to C, which encapsulates the principle of relativity. I came up with B on my own. With D and A you will get that the Earth clock and the ISS clock run at different rates. With B and C you will get that the Earth clock and the ISS clock run at the same rates. The beauty of GR is that it is a single law of physics which explains A, B, C, and D all together.
Off course I cannot disagree to that.
I was confused because I thought you did not agree to that, - when times ticks different, in different space-time, then each second also does, - whereby the comparable length off 1 second must be either stretching or shrinking. – So I expected a different kind of answer to your question, not easy to know what that possible could be.
Mentor
P: 17,527
 Quote by Bjarne whereby the comparable length off 1 second must be either stretching or shrinking.
So I still don't know how you plan on doing the comparison. For the fourth or fifth time, what method are you using to do the comparison? Feel free to simply use one of my four or come up with your own, but be specific.
 PF Gold P: 4,087 Bjarne, I find your post #154 difficult to follow. It is not logically argued and poses more questions than it gives answers. Have you seen this ? http://www-istp.gsfc.nasa.gov/stargaze/Smass.htm It is about experiments carried out on a space station. There is a universe of evidence that the laws of nature are the same everywhere. We know that atoms continue to emit and absorb the same pattern of spectral lines which have been recognised in millions of astronomical bodies. On a large scale, the GR cosmological models explain most of what we can measure about the universe. What you are proposing is 'new' physics. If the laws of nature really are laws of nature, they must apply everywhere. If there is experimental evidence to support it, then they must be modified, like relativity altered Newtonian concepts. Your position is impossible to argue unless you can produce this experimental evidence.
P: 344
 Quote by DaleSpam So I still don't know how you plan on doing the comparison. For the fourth or fifth time, what method are you using to do the comparison? Feel free to simply use one of my four or come up with your own, but be specific.
I cannot see this is neccesery
Either time is ticking different, or it is not.
According to relativity time is ticking different.
Many experiments and experiences confirm this.
So I still cannot see any point with the question.
Mentor
P: 17,527
 Quote by Bjarne I cannot see this is neccesery Either time is ticking different, or it is not. According to relativity time is ticking different. Many experiments and experiences confirm this. So I still cannot see any point with the question.
No, according to relativity, if you use methods B or C to do the comparison then time is the same, and only if you use methods A or D to do the comparison then is it different. There is no "hidden reality" under which you can simply say time is different or it is not. There are only experimental measurements, and relativity correctly predicts those.
P: 344
 B) Take a reference clock, physically transport it from one clock to the other and measure the rate of the reference locally at each clock
What do you mean by "measure the rate of the reference"
 Mentor P: 17,527 I mean to take the reference clock, place it locally next to the test clock (either the Earth clock or the ISS clock), and measure the duration of one "tick" of the reference clock using the local test clock.
P: 344
 Quote by DaleSpam So I still don't know how you plan on doing the comparison. For the fourth or fifth time, what method are you using to do the comparison? Feel free to simply use one of my four or come up with your own, but be specific.
B + C is local measurement
A + D is comparable measurement
I agree to all that, but it has not much with the question to do.
I do off course mean A+D

Do we know (for sure) whether distances are comparable different too, so as time and speed is (see A+D), - in different space-time.
I have read that mass-energy conservation will changes the Bohr radius, which also must apply to relativity?
Mentor
P: 17,527
 Quote by Bjarne I do off course mean A+D
Finally, a straight answer to such a basic question. It is a shame that it took so many posts to get to that.

 Quote by Bjarne Do we know (for sure) whether distances are comparable different too, so as time and speed is (see A+D), - in different space-time.
I see how to compare the time on two distant clocks using methods A or D. How would you propose to compare the different distances?

Please, let's not waste another dozen or more posts chasing this down. Just describe your experimental method of comparing two spatially separated distances as clearly and succinctly as possible.
P: 344
 Quote by DaleSpam Finally, a straight answer to such a basic question. It is a shame that it took so many posts to get to that.
I wrote comparable difference from the start.
It confused me you could misunderstand that so much.

 I see how to compare the time on two distant clocks using methods A or D. How would you propose to compare the different distances? Please, let's not waste another dozen or more posts chasing this down. Just describe your experimental method of comparing two spatially separated distances as clearly and succinctly as possible.
Good question.
I believe it is impossible.
Maybe only mathematical possible.
Already we compare space with a stretching rubber band, - or use the expression "curvature"
What does that mean?
Can we get closer to an understandable nature of that?
What happens with the ruler in such “bended” space? ( what do we know or not know)
At least seen from a mathematical perspective, is space stretching like the rubber band?

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