# What is a reference frame?

Discussion in 'Physics & Math' started by James R, Oct 13, 2004.

1. ### Quantum QuackLife's a tease...Valued Senior Member

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I do accept that we may be wrong in this but whatthis implies is that:

When the rest frame claims a distance recording for the othet ship. of say 10 meters. this is a now recording for our rest frame..yes?

However if we swap frames and claim a distance from our other frame this to must aslo be a NOW recording which means that the other frame [frame B] is 10 meters + 666 years at 0.8c away. [532 Light years + 10 meters away vs 10 meters]

so the location of each objects now in 3 dim space is vastly different depending on the amount of time difference beyween the NOWS.
If I am not mistaken this difference in Rest frame NOW location is never realised in most common SRT assessments. And I wonder why this is the case?
Also if you take it into the extreme and assume that the velocity has been maintained for millions of years this would further exasperate the situation to the point of absurdity if it isn't absurd already.
The question is:
Is this a valid assessment of the relativity of simultaneousness?

3. ### fo3acdcrocksRegistered Senior Member

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I don't think that we can say that the Nows are simoultaneous here. The ship is, in its Now, 532ly+10m away from the observer. For the ship it is reality, the ship is only in Now, its not ahead or after of any other frame.

We can't compare the Nows, since they are in different frames and for any frame, the only Now, that exists is that frames Now.

Oh.. and I don't think you can say 'the other frame is 10 meters away', since the frame has no coordinates, and takes up the entire space, we can only talk about distances between objects. Just thought I'd mention

5. ### Quantum QuackLife's a tease...Valued Senior Member

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then maybe it would be better to say we are comparing world time lines.

I guess what amazes me is that in all the discussions I have had about SRT RF it has never been mentioned that relative simultaneousness means also relative rest frame location.
SO a general statement like the following can clearly be stated:

"When declaring a rest frame the other object not at rest, can NEVER exist in the location determined by that rest frame if it has velocity."
The relativity of simultaneousness demands such a conclusion.

7. ### YuriyRegistered Senior Member

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1,080
QQ,
what you have just said? What the following set of words: "When declaring a rest frame the other object not at rest, can NEVER exist in the location determined by that rest frame if it has velocity." means? Do you check out the semantics (logic) of sentences that you print in your posts?

Last edited: Jan 13, 2005
8. ### Quantum QuackLife's a tease...Valued Senior Member

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Ha, Yuiry, I checked again and yes it still makes sense if you read it properly.
But I'll reword it again,

"When declaring a prefered rest frame the other object which has velocity can NEVER exist in or at the location determined by that prefered rest frame because to do so implies simultaneousness"

Is that better?

9. ### fo3acdcrocksRegistered Senior Member

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552
Then there is simultaneousness, but at the time of the event, the moving object has accumulated different time on its clock.
Lets say on the time of the event, the clock in the rest frame has accumulated x days.
If we want to see, what event happens in the moving objects rest frame, after x days have passed in the moving frame, then yes, the event is not the same event.

10. ### Quantum QuackLife's a tease...Valued Senior Member

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correct but I am talking about location and not just tick rates.

And to say that there is simultaneousness is contra to SRT.
Do you see the hmmmmm ......[ I don't like this word] paradox?

11. ### fo3acdcrocksRegistered Senior Member

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In the time of an event, where in the rest frame, the object seems to be 10m away, the object is 10m away. Just the accumulated time is different.
Anyway, this is just how I see it. It may not be true.

It seems, I don't follow your line of thought, so I don't see any paradox. If you'd try and explain more, then I'd probably catch up on you.

12. ### MacMRegistered Senior Member

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QQ,

When you say the location is not the same, are you trying to say when clocks agree the location will have changed? If so then I would agree.

13. ### fo3acdcrocksRegistered Senior Member

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Isn't that whats time dilation is all about? When you pick one location for an event, then the clocks can't agree on the time of its taking place. And when both clocks have accumulated the same amount of time, then they can't agree on the locations of things, since they are in different frames then. Assuming that the relative speed between the clocks is near c.

14. ### MacMRegistered Senior Member

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10,104
That appears to be a fair summation. The fact being missed by so many however is:

1 - SRT employs the Gamma function to compute time dilation, etc.

2 - GPS uses the Gamma function to adjust orbiting clocks.

3 - However, GPS is not using SRT.

The confusion seems to be that people forget that in SRT one can claim either clock as being at rest and it is the other clock that runs slow.

In the real world that is not what is happening. We have measured time dilation of a clock. But that is due to the Gamma function, indeed a form of Relativity but it is not the Relativity expoused by SRT because you can never declare the orbiting clock as being at rest and then see the another clock at the pole as in motion running slower.

The real world data is more closely aligned with Lorentz Relativity wherein one clock will indeed have a velocity greater than another clock and it will indeed dilate but you cannot and donot then claim that clock as being at rest and there being an equivelent "Relative" velocity between clocks which is reversable.

The faster clock will always be the clock in motion and will always be the clock that runs slow - Which is what happens in reality.

To try and claim SRT as valid results in physical clocks having to have multiple tick rates during the same test period; which simply does not happen and cannot happen.

In that regard GPS and other observations and data actually invalidate SRT but proves the Gamma function.

In GPS the orbiting clock has a velocity but claiming it as being at rest does not cause the pole to have a velocity since it is an arbitrary point without a dimension to have motion or velocity.

Velocity of the rotation of the earth varies with Latitude, at the pole the velocity is zero. If you were standing on the pole you would rotate and parts of your body would have a velocity of rotation but as you go inside your body to the finite point of the axis, dimension goes to zero and hence so does velocity.

SRT cannot be applied, only Gamma can be applied they are not the same thing .

GPS is compensating the orbiting clock for its orbital velocity and not as some velocity relative to another clock on the earth's surface.

Last edited: Jan 13, 2005
15. ### fo3acdcrocksRegistered Senior Member

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wasn't the slowing down of the orbiting clock supposed to be caused by the fact that it is in a weaker gravitational field?

16. ### MacMRegistered Senior Member

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No, just the opposite. In the weaker gravity it speeds up but collectively they pre-adjust the clock to compensate for increased speed by GR and dilation due to velocity (but only using the Gamma function since it is not an SRT reference frame. That is it cannot be reversed and claim the pole has velocity.

17. ### Quantum QuackLife's a tease...Valued Senior Member

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I am just focussed on the world time lines in specific the NOW regards this statement.
"When declaring a prefered rest frame the other object which has velocity can NEVER exist in or at the location determined by that prefered rest frame because to do so implies simultaneousness"

Because the other object can only be seen in it's past by the rest frame due to the lack of simultaneousness then when you swap frames the new rest frame is in a diferent location to what it was in it's past according to the original rest frame.

If we concentrate only on how the relative Nows work especially with velocity included you will see that the NOW is always the moment the rest frame records it's events. And it simply follows that if one frame has velocity the nows must be separated by the distance covered due to that time separation.[between the NOWs]

18. ### Quantum QuackLife's a tease...Valued Senior Member

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Simultaneousness of the nows is only assumed by the prefered rest frame.
The non-rest frame [NRF] has all the velocity.

The prefered rest frame can only record events in it's NOW and like wise with the NRF.

According to SRT the PRF NOW and the NRF NOW can not be simultaneous.
So therefore PRF is recording the location of the NRF in the NRF's past. As there is velcoity involved the NRF is actualy in it's NOW at a different location from it's Past as recorded by the PRF.

Say for arguments sake we consider the separation in time between NOWs to be one second. and the frames are separating at a rate of 0.8c

PRF will locate the NRF at a location that is one second into the NRF past.

At a velocity of 0.8c the NRF NOW location is 2398336 kms away. [0.8 * c]

The quetion is:

According to SRT:

If a clock is dilating does this mean the NOW of that clock is slowing as well there fore as the clock dilates are the relative NOWS becoming separated in time by that amount?

If so an object that has velocity and no available history could have extreme time separations in the Now.

If not then how is the time separation of relative simultaneousness calculated?
Obviously if we wish to know our frames locations we need to know how far in the past we are recording the other frame to be.

19. ### Quantum QuackLife's a tease...Valued Senior Member

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I have watched a whole heap of argument launched at various members of the forum [MacM being one of those memebers] that always finishes with quoting SRT's relativety of simultaneousness as the reason his and others arguments fail.

The pole and barn scenario for examples fails to place the pole and the barn in location. In that due to a lack of simultaneousness the barn and the pole can never be located at the same, location.

As far as I see it it all comes down to how simultaneousness or the lack there-of is handled.

SRT appears to set up a time paradox where the tick rates are not simultaneous [what ever that means!!!] but losing consistancy of application when dealing with the NOW.

An easy example is when we witnessed teh comet fragments hitting Jupiter. Acording to SRT this is a past event for the comet but a NOW event for us.

BUt where it gets dicky is that if that is teh case then Jupiter may not have been hit at all by those fagements as it's orbital position would have been different if we were riding on the comet and the comet would have missed hitting Jupiter all together. And if this is the case then the comet fragments are still out there having missed Jupiter x amount of years ago according to the comet RF.

So I see a paradox of relative NOW locations, and would suggest that if concentrated on we will find that the NOWS have to be simultaneous even if dilation has or is occuring

Which means that the universal time line is absolute where relative tick rates remain relative other wise we have a multi-verse universe in a physical sense and not just in the abstract sense. Which is what MacM has been arguing for ages.....

.

20. ### Quantum QuackLife's a tease...Valued Senior Member

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in summary : for two objects to collide in the usual physical sense their NOWS have to be simultaneous. SRT of course says otherwise, one object can collide with the past of another object. And of course the other object hasn't experienced that collision......

21. ### YuriyRegistered Senior Member

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QQ,
What kind of fantasies you will attribute SRT else?

22. ### MacMRegistered Senior Member

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Just a point of clarification. I have stated that to accept SRT one must accept the multiverse concept. I do not accept the multiverse concept and hence do not accept SRT.

To add substance to my position consider this. An orbiting clock has velocity. It is known to dilate relative to earth clocks (GR excluded) due to its motion. My arguement is that this dilation is due to motion perse' and not motion relative to earth clocks. There are those here that seem to think they can hide behind the guise of knowledge and claim this view is flawed and that indeed it is SRT.

I suggest they suck it in and either show mathematically correct responses to the following or zip it.

CASE IN POINT:

A clock has just been placed in a geosynchronous orbit with earth.

What is its tick rate relative to earth clocks (excluding GR affects); remember it has velocity, just not relative to earth clocks?

Are you going to argue it is not dilated? I suggest if you do you will find you are in error. You will find its tick rate is in Gamma proportion to each clock according to the clocks Latitude (hence different velocity).

That is you will find that ALL earth clocks have a different tick rate based on its velocity due to Latitude and so will the geosynchronous clock show dilation due to its velocity of orbit even though there is no relative velocity between it and the earth clocks.

Now prove me wrong by applying SRT and assume the geosynchronous clock to be at rest and please give me the relative tick rate of any clock on earth based on the relative velocity from that reference frame.

Last edited: Jan 14, 2005
23. ### Quantum QuackLife's a tease...Valued Senior Member

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Yuriy, I don't see why I should dignify your comment with a response.

I would ask the same thing of you: What kind of fantasies you will attribute to reality. else....?
It is obvious I wish to discuss relative simultaneousness in a way that is consistant but alas that dscussion is also a fantasy....