No 'ether'? Then how...

[swansont]

The distant stars are a convenient reference. But they are not a necessary reference.

[rrw4rusty]

REPLY: I do not truly understand the question. But, unless everything component of this scenario is at absolute zero degrees Kelvin. and nothing is moving, which is not the case in this scenario, some amount of kinetic energy is being generated however small that amount may be. Therefore some amount of electromagnetic waves are being generated from the spinning rod or the spinning barrel. This would seem to me to provide some frame of reference though I don`t see how this answers your question any more than I can see how the existence of an aether answers it. But if the existence of an aether answers your question the existence of these electromagnetic waves would serve the same purpose or so it would seem to me. ...Dr.Syntax

 

You've been really going after this with me and I so apprciate it! What tells the EM waves that 'this' is straight, that this is rotation and this is not?

 

See:

http://en.wikipedia.org/wiki/Mach%27s_principle

It hits the nail on the head (or did you send me this??!!??).

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The distant stars are a convenient reference. But they are not a necessary reference.

 

It's 3 AM here in San Diego... where do all of you people live, LOL!!!! Lots of interesting ideas have come in!

 

It was you that sent me:

http://en.wikipedia.org/wiki/Mach%27s_principle

 

Bravo! In looking at all your posts Mr. Bond, you've pointed out fallacies in other posts (ideas) while you've not attempted to offer a solution yourself ..BUT.. you did send me a link to the can of worms I was opening. Excellent work as a moderator!

 

My wife's already not talking to me lol and I don't need a frame of reference to see that! I'm going to bed.

 

Cheers,

Rusty

[Spyman]

so then, in a universe with no external references what defines this 'straight line'?

A person within the barrel would still be able to observe if the rod going through the barrow is straight or curved, and he could point out a straight line and realize that he would cross paths with the wall of the barrow if he tried to move straight in that direction.

 

Inside, the person holding on to the handle otherwise floats around watching the rod above him (...) turn. <snip> what's the difference between this and a situation where the person is pulled to the side of the barrow and watching the rod above him turning.

In a Universe with only a rod, barrow and the person inside, how would you get the rod or the barrow turning relative each others ?

 

Right from the start, the forces applied between them determines their relative speeds and while both would rotate, (in this case), the difference in Inertia between the objects is essential to their differences in angular momentum.

[dr.syntax]

Hello Rusty, I,Dr.Syntax, did NOT refer you to the: Mach`s Principle article. I am the one who explained that electromagnetic waves create their own medium so to speak for waves to travel through as they moved through space. I linked to that article that explained all that. You have to use the link in post #2 because the same web address to BOOKRAGS.com wll not come up with the same article if you try linking to the same web address at a later time.Their computer must have some time and date mechanism to produce different articles using the exact same web address. The only way I know of to get to that article is to scroll back to my first posting which is #2 in your thread. Enough of that. The important thing to keep in mind is that electromagnetic waves create their own medium for waves to travel through as they move through empty space. Also, as I said, I don`t truly understand your question to begin with. But if the existence of an aether explained it to you, then these electromagnetic waves would provide the for whatever it is this non existing aether was required to provide.They have no mass but do provide the means for their waves to move through empty space.It is explained in that article. Something to do with the electro field and the magnetic field moving together at a right angle to each other as the electromagnetic waves travel through space. These two fields moving through space perpendicular to each other ARE THE MEDIUM the waves move through.That is all I know about it. I don`t really understand your question to begin with. But if the existence of an aether answers your question, then I believe the nature of electromagnetic waves provides the answer as far as I can can figure it out. ...Dr.Syntax

[D H]

A person within the barrel would still be able to observe if the rod going through the barrow is straight or curved, and he could point out a straight line and realize that he would cross paths with the wall of the barrow if he tried to move straight in that direction.

You do not know that to be true because nobody does. You are assuming that the laws of physics in our huge and massive universe will hold in this toy universe. We do not know

• Why inertia arises,
  
• Why the equivalence principle holds, and
  
• Why inertial forces and torques vanish in a particular kind of frame of reference.

These are all axiomatic in physics.

[Spyman]

A person within the barrel would still be able to observe if the rod going through the barrow is straight or curved, and he could point out a straight line and realize that he would cross paths with the wall of the barrow if he tried to move straight in that direction.

You do not know that to be true because nobody does. You are assuming that the laws of physics in our huge and massive universe will hold in this toy universe. We do not know

• Why inertia arises,
  
• Why the equivalence principle holds, and
  
• Why inertial forces and torques vanish in a particular kind of frame of reference.

These are all axiomatic in physics.

Yes, I agree.

 

- But without assuming the same laws of physics, how are we supposed to discuss the comparison in the OP ?

[swansont]

Bravo! In looking at all your posts Mr. Bond, you've pointed out fallacies in other posts (ideas) while you've not attempted to offer a solution yourself ..BUT.. you did send me a link to the can of worms I was opening. Excellent work as a moderator!

 

As D H points out, the "why" of these are unsolved issues. So it shouldn't be surprising that I have not offered a solution.

[rrw4rusty]

You do not know that to be true because nobody does. You are assuming that the laws of physics in our huge and massive universe will hold in this toy universe. We do not know

• Why inertia arises,
  
• Why the equivalence principle holds, and
  
• Why inertial forces and torques vanish in a particular kind of frame of reference.

These are all axiomatic in physics.

 

The hypothetical universe in the OP 'is' our universe just modified as stated.

[Severian]

It is a fair enough question I think, and well enough posed. There is no need to involve electromagnetism in the discussion.

 

The 'true' answer (to the original question "Something knows if the rod is turning or, the barrow is turning. What is this something?"), in my opinion, is "the observer". Only the observer 'knows' which is turning, because it is only his subjective opinion.

 

What do I mean by that? I mean that without an observer, there is no difference. The turning of the rod and the turning of the barrel are indistinguishable. And to some extent they are even indistinguishable with an observer, so it is just his point of view that matters.

 

If we only allow Special Relativity for a moment, then we instantly see the distinction. One frame is inertial and one frame is non-inertial. The observer can tell if he is in a rotating frame or not because of the presence or otherwise of the centrifugal force, and this defines whether or not the barrel is rotating.

 

However, more correctly we should invoke GR, and admit that any apparent centrifugal force is possibly not a centrifugal force at all, but maybe the effect of curvature of space-time. So even if he feels the force, he may not be rotating.

 

In other words, the answer to the question is that there is no absolute sense of whether the rod or the barrel is rotating. It is simply a matter of reference frame.

[Moontanman]

Spinning a coin would allow you to know your were not in a gravity field. A spinning coin acts as a gyroscope and would not spin properly inside a rotating cylinder. It would fall over immediately.

[rrw4rusty]

It is a fair enough question I think, and well enough posed. There is no need to involve electromagnetism in the discussion.

 

The 'true' answer (to the original question "Something knows if the rod is turning or, the barrow is turning. What is this something?"), in my opinion, is "the observer". Only the observer 'knows' which is turning, because it is only his subjective opinion.

 

What do I mean by that? I mean that without an observer, there is no difference. The turning of the rod and the turning of the barrel are indistinguishable. And to some extent they are even indistinguishable with an observer, so it is just his point of view that matters.

 

If we only allow Special Relativity for a moment, then we instantly see the distinction. One frame is inertial and one frame is non-inertial. The observer can tell if he is in a rotating frame or not because of the presence or otherwise of the centrifugal force, and this defines whether or not the barrel is rotating.

 

However, more correctly we should invoke GR, and admit that any apparent centrifugal force is possibly not a centrifugal force at all, but maybe the effect of curvature of space-time. So even if he feels the force, he may not be rotating.

 

In other words, the answer to the question is that there is no absolute sense of whether the rod or the barrel is rotating. It is simply a matter of reference frame.

 

 

We paint the barrow white. So now lets say that unknown to the observer everything we have put together for this test is itself centered and aligned within a larger black barrow which has been hiding the rest of the universe. This larger black barrow, along with everything in it, is rotating in the opposite direction of the white barrow. Would you still get the centrifical force? No because in reality the spinning white barrow is acually standing still with respect to the universer at large. Something connected to the universe at large is reaching through and affecting our white barrow.

 

What is it?

 

Rusty

[J.C.MacSwell]

"Something must know" is an example of the pathetic fallacy.

 

Yes it is. So...? (what does that have to do with what I posted?)

 

Did you get from my post some implication that space somehow "understood" what it is doing? I can't see why that should be necessary.

 

Space has properties. I don't know the mechanism (or whatever it is) involved but it has properties that it orchestrates extremely consistently.

 

To me that is not nothing. It's something.

 

More of it, for instance, and it takes longer to traverse than less of it. If it was truly nothing it wouldn't make any difference.

[rrw4rusty]

"Something must know" is an example of the pathetic fallacy.

 

Knowing the definition of 'pathetic fallacy', Swanson's post only got a shake of the head from me. The phase means something like 'to treat an object as if it were a person with human feelings' and therefore technically speaking a case can be made for swansont being correct. However people commit pathetic fallacies all the time and, this phase has to be the most unfavorable sounding phase I've every heard. If a person did not know the definition it sounds like 'not only are flawed, you are pathetically flawed'. For myself, I would have to think twice about tossing it out in a post, LOL. The thing about posts is that what you post tends to reflect back on you more strongly than the person its directed at.

[Spyman]

Something connected to the universe at large is reaching through and affecting our white barrow.

 

What is it?

The geometry of spacetime permeates the Universe and can't be shielded.

[Severian]

We paint the barrow white. So now lets say that unknown to the observer everything we have put together for this test is itself centered and aligned within a larger black barrow which has been hiding the rest of the universe. This larger black barrow, along with everything in it, is rotating in the opposite direction of the white barrow. Would you still get the centrifical force? No because in reality the spinning white barrow is acually standing still with respect to the universer at large.

 

Why 'no'? What do you mean by 'in reality'? Whose reality? You have made no statement about the geometry of the space in which you sit (you have not specified a metric), so you don't know what gravitational forces you have. The space could be curved in such a way that you do feel a force, which you interpret as centrifugal and therefore insist that you are spinning and the black barrel not.

 

Something connected to the universe at large is reaching through and affecting our white barrow.

 

What is it?

 

I think you have implicitly assumed that you are in a flat spacetime, and it is that assumption which is fixing your frame. In a different reference frame (with relative acceleration), your geometry will be different (as given by GR).

[rrw4rusty]

The geometry of spacetime permeates the Universe and can't be shielded.

 

Spyman!

 

Thanks for replying! "The geometry of spacetime" (TGOS) sounds like a hammer hitting the nail on the head. But I'm not going to bob my head and with the wave of my hand, say 'Oh, TGOS... oh, like okay'.

 

Please help me out here, in any way you can.

 

If it determines whether you are turning or all the stars are turning it has to be more than just words, yes? Can you tell me what we know about it (or point to something that explains it) Has TGOS been detected? Do we know what it is? Do we know what carries it as it 'permeates' the universe? Do we know anything that can affect it? Is it gravity or related to it.

 

It is like gravity in that it communicates what is turning and what is not and what is accelerating and what is not much as gravity communicates what is up and what is down and what is escape velocity and what is not.

 

If there is something you can tell me, please try to indicate whether it is fact, theory or personal view point.

 

Thanks!

Rusty

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Why 'no'? What do you mean by 'in reality'? Whose reality? You have made no statement about the geometry of the space in which you sit (you have not specified a metric), so you don't know what gravitational forces you have. The space could be curved in such a way that you do feel a force, which you interpret as centrifugal and therefore insist that you are spinning and the black barrel not.

 

I think you have implicitly assumed that you are in a flat spacetime, and it is that assumption which is fixing your frame. In a different reference frame (with relative acceleration), your geometry will be different (as given by GR).

 

Severian!

Thank you for replying! I mean that -- your have a PhD and your fav area of sci is physics, input from you would be valued. In good faith I started to reply but regretably... you require too much data. I'm not saying that you do not need this data to respond, it is just that others can see what I'm after without wondering about things I did not mention such as gravity (as well as spacetime curvature??) and realities (not only 'which' lol but 'whose').

 

Actually it seems like you've lost patience and have just emptied a full magazine from your fully automatic question-gun into me... probably because you correctly see that I'm stumbling around trying to ask my real question, which today, LOL, seems to be "What propagates the geometry of spacetime?"

 

And, Re "Why no?" you're right, the black barrow is creating centrifugal force.

 

Cheers,

Rusty

[Severian]

I did not mention such as gravity (as well as spacetime curvature??) and realities (not only 'which' lol but 'whose').

 

I think gravity is rather essential if you are going to start discussing non-inertial frames. I don't see any way around that

[Spyman]

Can you tell me what we know about it (or point to something that explains it) ...

--> Albert Einsteins theory of Relativity.

 

"General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics. It unifies special relativity and Newton's law of universal gravitation, and describes gravity as a geometric property of space and time, or spacetime."

 

"General relativity's predictions have been confirmed in all observations and experiments to date."

http://en.wikipedia.org/wiki/General_relativity

 

I'm stumbling around trying to ask my real question, which today, LOL, seems to be "What propagates the geometry of spacetime?"

The geometry is not carried and does not propagate, it is already everywhere, if you have a Volume it has as minimum the properties of geometry for the space it contains.

 

Changes to the geometry of spacetime is thought to be like ripples that propagates with the speed of light.

 

"In physics, a gravitational wave is a fluctuation in the curvature of spacetime which propagates as a wave, traveling outward from the source. Predicted by Einstein's theory of general relativity, the waves transport energy known as gravitational radiation."

 

"Although gravitational radiation has not yet been directly detected, it has been indirectly shown to exist."

http://en.wikipedia.org/wiki/Gravitational_waves

[swaha]

if space is not nothing then what are its properties?

[ponderer]

Hi,

 

I've wanted to ask this question for decades and I'm sure it's the oldest, tiredest relativity question around.

 

Take a universe with nothing in it (or nothing visible) -- no external reference. Then take a barrow and drill a hole in the center of each end and place a rod through the barrow long enough to extend from each end. Now put some air in the barrow and a person. Finally weld a handle on the inside wall of the barrow.

 

Got all of that (know where this is going?)?

 

Place all of this in the frame-less universe and spin the rod that runs through the barrow. Inside, the person holding on to the handle otherwise floats around watching the rod above him (there's no 'above' but you know what I mean) turn. Okay. Got that pictured?

 

Why is there no centrifugal force? With no external frame of reference, no ether, no invisible space/time structure what's the difference between this and a situation where the person is pulled to the side of the barrow and watching the rod above him turning.

 

Something knows if the rod is turning or, the barrow is turning. What is this something?

 

Thanks,

Rusty

 

You have to be careful when you use the terms Ether or Aether, since they are associated with a classical notion of a cosmic gaseous medium. So any good anal retentive physicist is going to say, "Ether? Rubbish!"

 

You are discussing a space-time medium, I would presume, and not the classical Ether.

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if space is not nothing then what are its properties?

 

It has dimension. It is a medium for E-M and gravity waves. It has a speed limit. If you bend it, it distorts gravity and time. It forms potential wells. Brane theorists certainly seem to think it is something.

 

Let me ask you a fundamentally simple question. If space is nothing, with no properties, then what stands between things?

 

If there is nothing there, all things must be touching with no gaps between them. Poetically, space is nature's way of keeping us apart. (My wife is out of town)

 

It reminds me of an old saying. Time is nature's way of keeping everything from happening at once.

 

According to my way of thinking, once you accept that space-time is something, nothing else needs to exist, except energy.

 

Space-time is the canvas, and energy is the charcoal. All things are just geometric convolutions of space-time, sketched in energy density variations. Particles don't generate fields, and oscillations, they are the fields and oscillations. We just assign particle names to the various configurations, of fields and oscillations, but the particles themselves are just those fields and oscillations in the otherwise isometric space-time universal medium. It's like one of those pictures that are done by embossing. Think of space-time as the medium, copper, felt paper, brass, whatever, and energy is the raised embossing, but it is not static, it moves. Like the face in the sand storm in the Brendan Fraser version of the the movie The Mummy, or the face in the water, in the sequel. It's energy. It has to move. Quantization, and then chaos math for the dynamic system, generates the rest. <squirm> Get the picture?

 

It's a logical inversion of sorts. Instead of particles separated by empty space, we have just space-time, and particles are geometric blemishes of space-time. That geometry is sculpted in energy density variations, like waves on the ocean, but more prolific in its diversity of manifestations, and their compexity. Waves on the ocean are just a subset of the larger complexity.

Edited February 14, 2010 by ponderer
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[rrw4rusty]

You have to be careful when you use the terms Ether or Aether, since they are associated with a classical notion of a cosmic gaseous medium. So any good anal retentive physicist is going to say, "Ether? Rubbish!"

 

You are discussing a space-time medium, I would presume, and not the classical Ether.

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It has dimension. It is a medium for E-M and gravity waves. It has a speed limit. If you bend it, it distorts gravity and time. It forms potential wells. Brane theorists certainly seem to think it is something.

 

Let me ask you a fundamentally simple question. If space is nothing, with no properties, then what stands between things?

 

If there is nothing there, all things must be touching with no gaps between them. Poetically, space is nature's way of keeping us apart. (My wife is out of town)

 

It reminds me of an old saying. Time is nature's way of keeping everything from happening at once.

 

According to my way of thinking, once you accept that space-time is something, nothing else needs to exist, except energy.

 

Space-time is the canvas, and energy is the charcoal. All things are just geometric convolutions of space-time, sketched in energy density variations. Particles don't generate fields, and oscillations, they are the fields and oscillations. We just assign particle names to the various configurations, of fields and oscillations, but the particles themselves are just those fields and oscillations in the otherwise isometric space-time universal medium. It's like one of those pictures that are done by embossing. Think of space-time as the medium, copper, felt paper, brass, whatever, and energy is the raised embossing, but it is not static, it moves. Like the face in the sand storm in the Brendan Fraser version of the the movie The Mummy, or the face in the water, in the sequel. It's energy. It has to move. Quantization, and then chaos math for the dynamic system, generates the rest. <squirm> Get the picture?

 

It's a logical inversion of sorts. Instead of particles separated by empty space, we have just space-time, and particles are geometric blemishes of space-time. That geometry is sculpted in energy density variations, like waves on the ocean, but more prolific in its diversity of manifestations, and their compexity. Waves on the ocean are just a subset of the larger complexity.

 

I've been reading a lot on quantum physics lately and I'm in absolute agreement with the above. Lets not forget the Higgs field. Concerning the standard model and superstring/m theory, the question is out there: do these exist on 'something' not yet detected or do elementary particles/strings/3branes plus the soup of virtual particles (or the Higgs field) make up the base.

 

IMH view, space bends and you can't bend nothing. As for time... well, see my next thread.

 

Rusty