Can you determine absolute motion?

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  • #51
Physicist1231 said:
Now it may not have been the exact time that the observer thought they were syncronized but at some point in an absolute sense this was reached.
But it is not absolute; it is dependent upon the observer.

Absolute doesn't simply means synchronous from one observer's point of view; it means 'all possible observers agree'.

Two observers watching your setup will disagree on the timing of events. Neither is absolute. Both are relative (there's that word again).
 
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  • #52
Physicist1231 said:
So are you (jesseM) saying that you can never have anything syncronized in an absolute sense? Ever under ANY circum stances according to relativity?
Yes! That's what the word "relativity" means!
The simplest definition that we will use for simultanious is two actions occurring at the same time. As needed we can set that "according to X this is simultanious. But really I am looking in the absolute form.
It just plain doesn't exist.
 
  • #53
Physicist1231 said:
So are you (jesseM) saying that you can never have anything syncronized in an absolute sense? Ever under ANY circum stances according to relativity?
Well, if one frame's definition of coordinate simultaneity happens to match absolute simultaneity (assuming such a thing as absolute simultaneity exists, I don't believe in it myself but that's a philosophical issue), then synchronizing clocks in that frame would also synchronize them in an absolute sense. But relativity says that even if an absolute frame exists, no experiment would tell us which frame is the one whose definition matches the absolute one--if we had many sets of clocks synchronized in many different frames, God might be able to point at some set of clocks and say "those are the ones that are absolutely synchronized", but we mere humans would have no way of knowing experimentally which set (if any) was the one that was absolutely synchronized.
 
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  • #54
DaveC426913 said:
Absolute doesn't simply means synchronous from one observer's point of view; it means 'all possible observers agree'.

That is not true at all. Othewise there would be no absolute anything at all. (I am assuming this is your point though). As brought out in the previous setup it may not have been the same time PERCIEVED by the observer but rather that point of time where the clocks were truly and absolutely flashing at the same time. You know that according to the observer that he perceived Light A flash THEN Light B, Then they synced, then they were opposite. It happened somewhere in there... Questions is how to define it.

Logicly (as did Prof E.) he put a person (M) in the exact middle of two lightning pads (A and B). Provided the entire setup was at absolute rest the light would travel from each pad to the observer (equidistant from both) cover the same amount of distance (absolute distance) at the same velocity (absolute velocity of C) thus at the same time.

The only thing different about this limited point of view is that he is Equidistant from both events so he can accurately determinie simulnaity (spelling:() provided the entire body is at rest. Yet he would KNOW the entire setup was in motion if he knew he was equi distant and the light hit him at different times.
 
  • #55
jtbell said:
Two events (e.g. "clock A reads 10:48:00 PM" and "clock B reads 10:48:00 PM") can be simultaneous in at most one inertial reference frame.

Not quite. You can have one plane of people (imageine a two dimensional plane of receptors) and have a light on either side that intersects with a striaght line and prependicular to the pane. You now have everyone equidistant to each light. Every one has their own distance from the lights but if they measure the distance between them and both lights they will find it is equal.

With this setup if both lights flash at the same time everyone on that plane will percieve it Simultaniously (at different points in time) but percieve that both flashed at the same time.
 
  • #56
Physicist1231 said:
That is not true at all. Othewise there would be no absolute anything at all. (I am assuming this is your point though).
Without letting it get too general, yes.

Physicist1231 said:
As brought out in the previous setup it may not have been the same time PERCIEVED by the observer but rather that point of time where the clocks were truly and absolutely flashing at the same time. You know that according to the observer that he perceived Light A flash THEN Light B, Then they synced, then they were opposite.

Physicist1231 said:
It happened somewhere in there... Questions is how to define it.
Yes. It is defined as relative to the observer.

Each observer sees a point where the flashing lights flash simultaneously but they disagree on when that is. Thus it is not absolute, it is relative to the observer.


Simply put, if two events are separated in space then their time is relative to the observer. Full stop.

You are still confused about the meaning of absolute. Just because one observer sees two events to happen simultaneously does not mean that is an absolute phenomenon. For something to be absolute requires that all possible observers will come to the same conclusion.
 
  • #57
DaveC426913 said:
You are still confused about the meaning of absolute. Just because one observer sees two events to happen simultaneously does not mean that is an absolute phenomenon. For something to be absolute requires that all possible observers will come to the same conclusion.

Absolute does not mean that ALL observers agree. Rather it is the difference between Actuallity and Perception. Observers can percieve something but that may not have been what ACTUALLY happened. Absoluteness in this sense is defining what is actually happening in space and time no matter how it is perceived by a limited reference point.
 
  • #58
DaveC426913 said:
No. Geometrically your setup does not work.

We can make it more simple.

Light A is at -10ls,0,0
Light B is at 10ls,0,0
Observer is at 0,0,0

Light A and B emit light at the same time

Provided that the entire setup is motionless the observer will see the lights flash at the same time

Move the observer to 0,5ls,0 and he will observe the same thing just takes a fraction of a second longer to see them.

Move to 0,5ls,5000ls and he will still observe that both happened at the same time. just takes a lot longer to see it.
 
  • #59
Physicist1231 said:
We can make it more simple.

Light A is at -10ls,0,0
Light B is at 10ls,0,0
Observer is at 0,0,0

Light A and B emit light at the same time

Provided that the entire setup is motionless the observer will see the lights flash at the same time

Move the observer to 0,5ls,0 and he will observe the same thing just takes a fraction of a second longer to see them.

Move to 0,5ls,5000ls and he will still observe that both happened at the same time. just takes a lot longer to see it.

Yes. you have shown that, relative to two observers of your choice, they agree that two events have occurred simultaneously.

So what?

That is not absolute. As witnessed by a third observer, who comes in with an equally valid observation and says the events occurred separate in time. And he'd be right.

You still don't get 'absolute'. It does not mean that two observers of your choice agree. Or a hundred. Or a thousand.

It means that their conclusions are independent of their position. i.e. your observers could move their position all they want (an infinity of choices) and still arrive at the same conclusion. That would make it absolute, instead of relative to their position.
 
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  • #60
jtbell said:
Two events (e.g. "clock A reads 10:48:00 PM" and "clock B reads 10:48:00 PM") can be simultaneous in at most one inertial reference frame. Even this "single-frame simultaneity" is possible only if no signal traveling at a speed less than or equal to c can "connect" the two events. If such a signal can connect the two events, then they cannot be simultaneous in any inertial reference frame, because the signal would travel instantaneously in such a frame.

Dave,

that setup was mainly for this quote here. not really defining absolute anything. He mentioned that things can only be perceived as simultanious ant at max one point at a time. I was simply showing otherwise.
 
  • #61
DaveC426913 said:
Yes. you have shown that, relative to two observers of your choice, they agree that two events have occurred simultaneously.

So what?

That is not absolute. As witnessed by a third observer, who comes in with an equally valid observation and says the events occurred separate in time. And he'd be right.

You still don't get 'absolute'. It does not mean that two observers of your choice agree. Or a hundred. Or a thousand.

You are correct so take out the "limited point of view" since they cannot be trusted. Toss something else into the mix. The Omnipotent Point of view. This view is not limited by space or time.

With this said this OPOV will be able to stop everything as if taking a 3d picture and can then traverse the environment (without time passing for any object).

To determine if Both light A and B flashed at the same time the OPOV analyses each frame of time taken.

This comes back to the difference between Actuality (absolute measurements) and Perception (how it is perceived by others).

In each time frame the OPOV goes to the exact location of Light A.

If light is present in that point in time then move to Light B.

If light exists at Point B then both lights are on at the same time.

He can then go back one unit of time (what ever that would be, second, microsecond, nanosecond ect) and where one moment of time both are off and the next moment in time they are perceived on (according to the OPOV as defined above) then this could be considered the the absolute sense that the lights flashed at the same point in time regardless of how they are perceived by a limited pov.
 
  • #62
Physicist1231 said:
that setup was mainly for this quote here. not really defining absolute anything. He mentioned that things can only be perceived as simultanious ant at max one point at a time. I was simply showing otherwise.

You're battling trivialities while missing the bigger picture.
 
  • #63
Physicist1231 said:
You are correct so take out the "limited point of view" since they cannot be trusted. Toss something else into the mix. The Omnipotent Point of view.
No!

They can be trusted! They are perfectly correct!

There is no omnipotent point of view!

Argh!
 
  • #64
Physicist1231 said:
You are correct so take out the "limited point of view" since they cannot be trusted. Toss something else into the mix. The Omnipotent Point of view. This view is not limited by space or time.
No such thing as omnipotent PoV

With this said this OPOV will be able to stop everything as if taking a 3d picture and can then traverse the environment (without time passing for any object).
No such thing as an absolute snapshot.

To determine if Both light A and B flashed at the same time the OPOV analyses each frame of time taken.

This comes back to the difference between Actuality (absolute measurements) and Perception (how it is perceived by others).
No such thing as an actual measurement.

In each time frame the OPOV goes to the exact location of Light A.
No such thing.

If light is present in that point in time then move to Light B.

If light exists at Point B then both lights are on at the same time.

He can then go back one unit of time (what ever that would be, second, microsecond, nanosecond ect) and where one moment of time both are off and the next moment in time they are perceived on (according to the OPOV as defined above) then this could be considered the the absolute sense that the lights flashed at the same point in time regardless of how they are perceived by a limited pov.

Physicist1231, this is a complete lack of understanding of Einsteinian spacetime. You are using a classical Newtonian model, where space and time are absolute and unchanging backdrops against which all things can be measured.

The classical Newtonian model has been replaced with the Einsteinian model, which has been shown to be correct in what is arguably the most well-tested theory in the history of science.

The very fundamental principle of Einsteinian relativity is exactly this: simultaneity of events is relative to the observer's frame of reference. All other phenom fall out of this one.

Your arguiments are all based on an out-of-date model that has been shown to be false in literally uncountable experiments.
 
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  • #65
Honestly, I may catch some slack for this because relativity does not explicitly make this claim, but it is actually much easier to understand if you take it a step further in that not only can absolute motion not be measured, but it doesn't exist.
 
  • #66
Physicist1231 said:
He mentioned that things can only be perceived as simultanious ant at max one point at a time. I was simply showing otherwise.

In relativity, different "reference frames" refer to observers that are moving relative to each other. Two observers at different locations, and at rest with respect to each other, both observe the same two events to be simultaneous (or not), after correcting for signal-travel time from the events. Two observers that are moving with respect to each other, differ in their observation of the time interval between two events.

When we talk about a "reference frame" we are talking about the whole collection of possible observers that are stationary with respect to each other, and who are at rest in that reference frame.
 
  • #67
1MileCrash said:
Honestly, I may catch some slack for this because relativity does not explicitly make this claim, but it is actually much easier to understand if you take it a step further in that not only can absolute motion not be measured, but it doesn't exist.

Good point.

(But if one were going to catch anything, it would be not slack, it would be flak. They're kind of opposites. :wink:)

http://en.wikipedia.org/wiki/Flak_(disambiguation)"
 
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  • #68
Too early, they rhyme, close enough. :)
 
  • #69
Don't know if troll... or just very stubborn...
 
  • #70
jeppetrost said:
Don't know if troll... or just very stubborn...

No call for that.
 
  • #71
AFAIK Newton proposed absolute space (such as with his rotating bucket experiment) and it got hammered away a bit by Mach, but then Einstein came forth and basically said "space isn't absolute -- spacetime is." So in other words, the spacetime continuum is an "absolute" concept where you're trading off motion in time for motion in space. Acceleration and gravity, according to Einstein, are the same thing. Space and time fall out of sync in different inertial frames.
 
  • #72
DaveC426913 said:
Physicist1231, this is a complete lack of understanding of Einsteinian spacetime. You are using a classical Newtonian model, where space and time are absolute and unchanging backdrops against which all things can be measured.

The classical Newtonian model has been replaced with the Einsteinian model, which has been shown to be correct in what is arguably the most well-tested theory in the history of science.

The very fundamental principle of Einsteinian relativity is exactly this: simultaneity of events is relative to the observer's frame of reference. All other phenom fall out of this one.

Your arguiments are all based on an out-of-date model that has been shown to be false in literally uncountable experiments.

It is not really a lack of understanding of Einsteinian spacetime rather reviewing history as to why the classical Newtonian model has been replaced with the Einsteinian model.

Doing the research (really getting off topic though) you will find that the notion if time dilation was perceived where an object in motion at a high rate did not seem to tick the same time as it did on earth. This may have been with the satelites in space or perhaps rocket launches. We as the world saw a phenomonon and wanted to find out what was causing this. Galileo tried to do this with the Galilian transformation. This was using the Newtonian modle and the assumption that space and time have rigid values though they can be perceived differently. This proved to be inaccurate (in 3d space where it did work in a one dimensional space, the level of inaccuracy increased as speeds increased). About the same time the failure was noted the Lorentz Transformation came about with a completely new thought process of time and space being flexible. Einstein took this idea and ran with it to develop GR and SR. Thus completely abandoning the Newtonian physics.

This was a very dramatic and rapid change in the scientific thought process. So rapid in fact that no one looked back to see why the Galilean Transformation was incorrect while using Newtonian physics (which ALWAYS worked accuratelty for any previous experiment).

In short things can be explained using Newtonian Physics using a rigid strucutre of spacetime, its just that Galileo failed at that attempt and science ran in a different direction.

One of the largest supporting expiriments that is used to support the theories of SR and GR for time dilation is the Hafele–Keating expiriment. This has since been debunked by even Dr. Keating himself.

http://www.google.com/url?sa=t&source=web&cd=4&ved=0CCoQFjAD&url=http%3A%2F%2Fwww.shaping.ru%2Fcongress%2Fenglish%2Fspenser1%2Fspencer1.asp&ei=yl7JTbnALs3Lswao75CQAw&usg=AFQjCNHWdDddqaNxYeKn-egojeHvd64BRQ

http://www.google.com/url?sa=t&sour...75CQAw&usg=AFQjCNFC78HsYCpF2GNd_dvwtC0_IU0-fg

http://www.google.com/url?sa=t&source=web&cd=9&ved=0CFEQFjAI&url=http%3A%2F%2Fwww.phil-inst.hu%2F~szekely%2FPIRT_BP_2%2Fpapers%2FNAWROT_09_FT.doc&ei=yl7JTbnALs3Lswao75CQAw&usg=AFQjCNGuyJ40-VXlCoDs0uHomjbfDDSZJw

http://www.anti-relativity.com/hafelekeatingdebunk.htm

The raw data was not looked at by majority of the scientific community because of the attitude of "hey they did it and it worked!" rather than looking at the results as to why the original conclusion was that it worked.
 
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  • #73
Wait a second here are you trying to say that time dilation is a farce?
 
  • #74
Physicist1231 said:
We can make it more simple.

Light A is at -10ls,0,0
Light B is at 10ls,0,0
Observer is at 0,0,0

Light A and B emit light at the same time

Provided that the entire setup is motionless the observer will see the lights flash at the same time

Move the observer to 0,5ls,0 and he will observe the same thing just takes a fraction of a second longer to see them.

Move to 0,5ls,5000ls and he will still observe that both happened at the same time. just takes a lot longer to see it.
How does this conflict with jtbell's statement that events are only simultaneous in one frame? If those two observers are at rest in the coordinate system where you are giving the position coordinates, then they are normally said to share the "same frame", it doesn't matter if their positions are different. If the two observers have different velocities and just happen to be at those positions when the light strikes them, then as I already told you before, saying events are simultaneous in your frame is not the same as seeing the light from them simultaneously, in their own frame the activation of light A and B may not have happened at the same distance from their own position, in which case seeing the light from them simultaneously implies they did not occur simultaneously in their own frame.

Nevertheless jtbell's statement is slightly inaccurate if we are talking about a space with more than 1 dimension, in this case it is possible for two frames to judge the same pair of events to be simultaneous, but only if the spatial axis between the events is orthogonal to (at right angles to) the axis of motion between the two frames. For example if two events happen at x=0,y=0,t=0 and x=10,y=0,t=0 in my frame, and you are moving along my y-axis but you have zero velocity along the x-axis, then in your frame the events are still simultaneous.
 
  • #75
Physicist1231 said:
It is not really a lack of understanding of Einsteinian spacetime rather reviewing history as to why the classical Newtonian model has been replaced with the Einsteinian model.
Because it has been shown to be false. You made incorrect assertions. We showed them to be wrong. This should have been a very short thread.

Physicist1231 said:
Galileo tried to do this with the Galilian transformation. This was using the Newtonian modle and the assumption that space and time have rigid values though they can be perceived differently. This proved to be inaccurate (in 3d space where it did work in a one dimensional space, the level of inaccuracy increased as speeds increased). About the same time the failure was noted the Lorentz Transformation came about with a completely new thought process of time and space being flexible. Einstein took this idea and ran with it to develop GR and SR. Thus completely abandoning the Newtonian physics.

This was a very dramatic and rapid change in the scientific thought process. So rapid in fact that no one looked back to see why the Galilean Transformation was incorrect while using Newtonian physics (which ALWAYS worked accuratelty for any previous experiment).

In short things can be explained using Newtonian Physics using a rigid strucutre of spacetime, its just that Galileo failed at that attempt and science ran in a different direction.

So, you are championing classical Newtonian model with fixed background of space and time, or are you here to champion the Galilean Transform? If the former, every experiment in the last 80 years has refuted it. If the latter, why are you not using it to make your case here? Why are we still discussing events of simultaneity in classical Newtonian model with no modifications?

We have been taking your statements at face value. And at face value they are incorrect.

Seems kind of disingenuous to claim that you've been playing your cards close to your chest all along, stringing us along with all this talk of Newtonian classical space and time.

Are you conniving aforethought? Or are you backpedaling to save face? Got to be one of the two.

Perhaps it's time to close this thread and open a new one making your case for the resurgence of the Galilean Transform.
 
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  • #76
Physicist1231 said:
One of the largest supporting expiriments that is used to support the theories of SR and GR for time dilation is the Hafele–Keating expiriment. This has since been debunked by even Dr. Keating himself.

http://www.google.com/url?sa=t&source=web&cd=4&ved=0CCoQFjAD&url=http%3A%2F%2Fwww.shaping.ru%2Fcongress%2Fenglish%2Fspenser1%2Fspencer1.asp&ei=yl7JTbnALs3Lswao75CQAw&usg=AFQjCNHWdDddqaNxYeKn-egojeHvd64BRQ

http://www.google.com/url?sa=t&sour...75CQAw&usg=AFQjCNFC78HsYCpF2GNd_dvwtC0_IU0-fg

http://www.google.com/url?sa=t&source=web&cd=9&ved=0CFEQFjAI&url=http%3A%2F%2Fwww.phil-inst.hu%2F~szekely%2FPIRT_BP_2%2Fpapers%2FNAWROT_09_FT.doc&ei=yl7JTbnALs3Lswao75CQAw&usg=AFQjCNGuyJ40-VXlCoDs0uHomjbfDDSZJw

http://www.anti-relativity.com/hafelekeatingdebunk.htm
I don't think any of these papers has been published in a peer-reviewed mainstream source, you can find all sorts of crackpot claims if you look around at random websites, including authors who apparently misunderstand the techniques used to get final values from the raw data, see the note in blue here. In any case the Hafele-Keating experiment has been repeated at later times with more accurate clocks and the results continue to confirm the predictions of relativity, see for example http://www.npl.co.uk/upload/pdf/metromnia_issue18.pdf where they found:
On return to NPL the traveling clock was predicted to have gained 39.8 ns, including
an additional geometric factor. This compared remarkably well with a measured gain of 39.0 ns. We estimated the uncertainty due to clock instabilities and noise to be around ±2 ns.
 
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  • #77
SeventhSigma said:
Wait a second here are you trying to say that time dilation is a farce?

Not completely. People percieve time differently but this does not mean that Time in an absolute sense is flexible. Just able to be perceived differently. Again the difference between Actuallity and Perception.
 
  • #78
Physicist1231 said:
Not completely. People percieve time differently but this does not mean that Time in an absolute sense is flexible. Just able to be perceived differently. Again the difference between Actuallity and Perception.

But relativity is all about coming to conclusions *after all observations have been made*. Besides, perception is all we have to define our reality, so evidence has to be taken very seriously. And the evidence, to date, points to relativity as being more consistent than the Newtonian sense where "absolute space" is concerned.
 
  • #79
Physicist1231 said:
Not completely. People percieve time differently but this does not mean that Time in an absolute sense is flexible. Just able to be perceived differently. Again the difference between Actuallity and Perception.
In relativity you are free to believe in the "actuality" of absolute space and time (though most people who accept relativity probably see no need for such an idea, as 1MileCrash suggested), as long as you accept that there would be no experimental way to determine the truth about things like absolute velocity and absolute simultaneity. If you think there would be, then you must reject some aspect of relativity, but you're going to have a very hard time constructing a theory that rejects some part of relativity but is consistent with so much experimental evidence that seems to support it.
 
  • #80
DaveC426913 said:
Perhaps it's time to close this thread and open a new one making your case for the resurgence of the Galilean Transform.

Tried that and got shot down and the thread was deleted... so I am asking individual questions to gain a better understanding.
 
  • #81
SeventhSigma said:
But relativity is all about coming to conclusions *after all observations have been made*. Besides, perception is all we have to define our reality, so evidence has to be taken very seriously. And the evidence, to date, points to relativity as being more consistent than the Newtonian sense where "absolute space" is concerned.

So if no one perceives an event did it actually happen? If we only base reality on what we as a group or individuals percieve then we will wind up with holes of unexplained things.

Classic example. If a tree falls in the woods and no one hears it, did it make a noise?
 
  • #82
JesseM said:
In relativity you are free to believe in the "actuality" of absolute space and time (though most people who accept relativity probably see no need for such an idea, as 1MileCrash suggested), as long as you accept that there would be no experimental way to determine the truth about things like absolute velocity and absolute simultaneity. If you think there would be, then you must reject some aspect of relativity, but you're going to have a very hard time constructing a theory that rejects some part of relativity but is consistent with so much experimental evidence that seems to support it.

so what you are saying is that i have a chance?
 
  • #83
Physicist1231 said:
Tried that and got shot down and the thread was deleted... so I am asking individual questions to gain a better understanding.
But your premises are all wrong.

You postulate an omniscient viewpoint where none exists.

You have an arbitrary number of observers at arbitrary locations. They observe some events and disagree on when they occurred.

Start from there.


Physicist1231 said:
So if no one perceives an event did it actually happen? If we only base reality on what we as a group or individuals percieve then we will wind up with holes of unexplained things.

Classic example. If a tree falls in the woods and no one hears it, did it make a noise?
Let's not get philosophical.

In this practical case you have observers. They observe. We need to explain what they observe.
 
  • #84
Physicist1231 said:
so what you are saying is that i have a chance?
Only if by "chance" you mean that it's logically possible to have a theory where almost all phenomena behave as relativity predicts but with some rare and so-far unobserved exceptions that might established a preferred frame (something like a Lorentz ether theory where nearly all phenomena length-contract and time-dilate when moving relative to the preferred frame, but there are a few exceptions). But you don't have a chance if you want to disprove relativity just by thought-experiments and theoretical arguments, it is provably self-consistent mathematically, the only way to show it is flawed would be to go out and do some new experiment no one has ever tried and find clear-cut observations of a phenomena that doesn't obey Lorentz-symmetric laws.
 
  • #85
DaveC426913 said:
But your premises are all wrong.

You postulate an omniscient viewpoint where none exists.

You have an arbitrary number of observers at arbitrary locations. They observe some events and disagree on when they occurred.

Start from there.



Let's not get philosophical.

In this practical case you have observers. They observe. We need to explain what they observe.

You say that none exists. Do you say that becase we have never discovered one? Thousands of years ago if I said that atoms existed I might get the same reaction.
 
  • #86
DaveC426913 said:
So, you are championing classical Newtonian model with fixed background of space and time, or are you here to champion the Galilean Transform?

Actually I would support the Newtonian model but not really the Galilean transform. Galileo had the right idea but the formula was incomplete.
 
  • #87
Physicist1231 said:
You say that none exists. Do you say that becase we have never discovered one? Thousands of years ago if I said that atoms existed I might get the same reaction.

Correct. Thousands of years ago we did not have the scientific method. We've advanced a little since then.

Consequently, in this day and age we try not to explain the universe by resorting to the existence of God and his Omniscient viewpoint.

You'll not make a lot of progress here on PF singing that tune.
 
  • #88
DaveC426913 said:
Correct. Thousands of years ago we did not have the scientific method. We've advanced a little since then.

Consequently, in this day and age we try not to explain the universe by resorting to the existence of God and his Omniscient viewpoint.

You'll not make a lot of progress here on PF singing that tune.

LOL I was not trying to bring The Almightly into this. I could... but won't in this case. I was simply using the Omnipotent POV to express it is not limited to Space and time.

But part of theories is to find out the implications of what you are saying.

If we were (and don't shoot me for saying) to use Newtonian Physics in calculating things like time Dilation then we would not be removing Relativity. Merely, redefining it. Is it completely impossible that NONE of GR and SR is wrong?
 
  • #89
Physicist1231 said:
LOL I was not trying to bring The Almightly into this. I could... but won't in this case. I was simply using the Omnipotent POV to express it is not limited to Space and time.
How can you have the latter without the former? That's a rhetorical question. The latter implies the existence of the former. We do not ascribe to the existence of the former.

An omnipotent PoV is beyond science. You cannot invoke it as a valid argument.


Physicist1231 said:
If we were (and don't shoot me for saying) to use Newtonian Physics in calculating things like time Dilation then we would not be removing Relativity. Merely, redefining it. Is it completely impossible that NONE of GR and SR is wrong?
Why don't you start with the results of the experiments? We have ample evidence of time dilation; Einsteinain SR and GR explain it very well. The Newtonian model does not.

Why are you trying to fix what ain't broke? What is the impetous driving your desire to find another answer when we have an answer?
 
  • #90
Physicist1231 said:
Thousands of years ago if I said that atoms existed I might get the same reaction.
Thousands of years ago the ancient Greek philosophers postulated atoms, that is where the word came from. But that is not the point. The point is that there is no experimental evidence in favor of an absolute reference frame. This means that it is not necessary in order to explain experimental results and, if it exists, it does not significantly impact any experimental data obtained to date.

Physicist1231 said:
I was simply using the Omnipotent POV
The word is "omniscient" meaning all-knowing, not "omnipotent" meaning all-powerful.

Physicist1231 said:
If we were (and don't shoot me for saying) to use Newtonian Physics in calculating things like time Dilation
Nonsense. Time dilation is not part of Newtonian physics.

Re your OP. There is no way to detect absolute motion. Your proposed device would not register any inertial motion effects. You should learn the Lorentz transform and do the derivation yourself. It will be very instructive for you.
 
  • #91
Interesting topic!

What about this scenario using gravity or acceleration to prove absolute motion. By the way, I don’t know the math on this but it still seems a good thought experiment so here goes:

Let’s say I am in a space ship, with no thrusters or power on, so all I know is that I could be traveling at some speed. So I can say that I am in an inertial reference frame.

I know that if I change direction but not speed I will still be accelerating. I also know that I will be able to measure the rate I accelerate by using something like a pendulum or some other device that would move when I accelerate.

I know the mass of my ship. So I can calculate that if I was traveling at speed ‘x’how much thrust (power) I would need to turn the ship through 90 degrees in a particular direction. I would also be able to calculate the effects of gravity (acceleration) on my pendulum.

So I execute the manoeuvre and measure the effect on my pendulum. If the pendulum swings the calculated amount I know what speed I was traveling at prior to the manoeuvre.

If the pendulum doesn’t swing the calculated amount I could then work out what speed I was moving at prior to the manoeuvre.

Therefore I can show that I was in motion (or not) without making reference to another frame.
 
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  • #92
rede96 said:
Let’s say I am in a space ship, with no thrusters or power on, so all I know is that I could be traveling at some speed. So I can say that I am in an inertial reference frame.

I know that there if I change direction but not speed I will still be accelerating. I also know that I will be able to measure the rate I accelerate by using something like a pendulum or some other device that would move when I accelerate.

I know the mass of my ship. So I can calculate that if I was traveling at speed ‘x’how much thrust (power) I would need to turn the ship through 90 degrees in a particular direction. I would also be able to calculate the effects of gravity (acceleration) on my pendulum.

So I execute the manoeuvre and measure the effect on my pendulum. If the pendulum swings the calculated amount I know what speed I was traveling at prior to the manoeuvre.
Why do you think it would depend in any way on your initial speed? Of course in relativity there is no objective truth about your initial speed, but different frames who define your coordinate speed differently can apply the same laws to your ship and pendulum to predict how it will behave, and all will predict the same thing for the angle the pendulum moves (not necessarily the angle in their frame, but if the pendulum string is initially lined up with the 0-degree mark on a circular protractor on board your ship, all frames predict the same thing about what mark it's lined up with at the end of the maneuver).
 
  • #93
I don't think we can ever prove absolute space. Everything sitting still and everything moving at constant velocity V would look the same. We can only define motion in the relative sense.
 
  • #94
Nay sirs,

He who accelerates has the slow clock,

the spacefarer must launch and accelerate to leave, then decelerate, turn around and accelerate to return, then decelerate to land.

The people who stay behind do not experience these effects which are general (not special) relativistic, the difference in clock times are due to general relativity.
 
  • #95
xxxx0xxxx said:
Nay sirs,

He who accelerates has the slow clock,

the spacefarer must launch and accelerate to leave, then decelerate, turn around and accelerate to return, then decelerate to land.

The people who stay behind do not experience these effects which are general (not special) relativistic, the difference in clock times are due to general relativity.
You're correct that if one accelerates and the other doesn't, then the one that accelerated is always the one to have aged less. However, as long as spacetime is flat (no curvature due to mass/energy) there is no need for general relativity, you can calculate the behavior of an accelerating object (including the time that elapses between two points on its worldline) just fine using an SR inertial frame.
 
  • #96
JesseM said:
Why do you think it would depend in any way on your initial speed?

I was thinking that if I was to use lateral thrusters, the amount of thrust I would need to turn the ship 90 degrees would depend on the speed I was travelling. The faster I was going the more thrust I need.

Something like it takes more force to change the direction of moving object then a static one, as a moving object’s mass increases. (E= mc2) the faster it goes. So if it took more force to change direction then I must have gathered more than my rest mass and thus must be ‘moving’
 
  • #97
rede96 said:
I was thinking that if I was to use lateral thrusters, the amount of thrust I would need to turn the ship 90 degrees would depend on the speed I was travelling. The faster I was going the more thrust I need.

Something like it takes more force to change the direction of moving object then a static one, as a moving object’s mass increases. (E= mc2) the faster it goes. So if it took more force to change direction then I must have gathered more than my rest mass and thus must be ‘moving’
No. In your reference frame your mass does not increase. You are - as far as any (local) experiment can detect (including accelerating your craft in any direction) - as good as stationary.
 
  • #98
DaveC426913 said:
No. In your reference frame your mass does not increase. You are - as far as any (local) experiment can detect (including accelerating your craft in any direction) - as good as stationary.

As I understood it the reason I can’t travel at c is that the energy I would need would reach infinity as my mass would keep increasing proportionately.

So I assume that mass does increase but would revert back to its rest mass once I stop accelerating. Is that correct?
 
  • #99
rede96 said:
As I understood it the reason I can’t travel at c is that the energy I would need would reach infinity as my mass would keep increasing proportionately.

This is how it would look to an observer you left behind when you started accelerating. In your frame ( spaceship ?) you would notice nothing untoward, your motors will push you along just as they did when you started. If you keep firing the engines long enough, a horizon will spring up between you and the left-behind observer.

So I assume that mass does increase but would revert back to its rest mass once I stop accelerating. Is that correct?

There's no actual mass increase, but when you stop accelerating the horizon will disappear.

Have a look at this article

http://gregegan.customer.netspace.net.au/SCIENCE/Rindler/RindlerHorizon.html
 
  • #100
Mentz114 said:
In your frame ( spaceship ?) you would notice nothing untoward, your motors will push you along just as they did when you started.

Agreed. This is key.

Under your constant thrust, your pendulum would continue to stay as tilted a year from now as it does today. Again, no local experiment would indicate your velocity. (Though you could look out the window and see the galaxy passing by at .9999c.)
 
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