Is Relativity Reality?

[mistermack]

Same old same old, childinazoo. Not even worth this comment.

[colubridae]

Same old same old, childinazoo. Not even worth this comment.

Same old same old, mistermack. Not even worth this comment.

[mistermack]

I said earlier that I'd seen a flaw in my own argument, that probably invalidated my conclusion. Since nobody else spotted it, here it is:

I wrote 'Now introduce one more particle, and it's travelling towards the first one at 100,000 kps so it's velocity is along the X axis. Now you have a problem. If you choose a frame for the original particle that is moving along the X axis towards the second particle and it's velocity is more than 200,000 kps, then the second particle is travelling in that frame at more than 300,000 kps, or more than the speed of light.'

That's where the flaw crept in. The second particle travels towards the first one at 100,000 kps. BUT ONLY IN ONE FRAME! For any other reference frame, time dilation will alter the 100,000 quantity.
So if you want to stick to the 100,000 figure, then for any other frame, you are actually dealing with DIFFERENT PARTICLES. Either way, the conclusion doesn't stand.

On the claim I made, that there IS one real reference frame, that everything moves relative to, then this clearly isn't proved.
But I've yet to see it disproved. When you read about SR, you are always told that every inertial reference frame works equally well, and is equally valid, and that there is no 'real' or 'favoured' frame.
I concede the 'works-equally-well' bit, but not the other. If there was one 'real' reference frame, nothing would change. You can convert from any chosen frame to that one, just as you can to any other. So the convertability of frames does not in itself rule out a single 'real' frame.
I haven't seen any proof, or any mention of a proof, that there is no favoured frame. I've seen it claimed many times, but never seen any reason as to why.
The fact that the speed of light is independent of the motion of the source, and always the same figure, surely points to it being a charcteristic of an enabling medium of some sort, even if it doesn't conform to what we think of as a material medium.

Does anyone have a reference for a proof that there is no 'real' frame? ( The Lorenz transformations simply prove that you can 'consider' particles as moving in different frames, and get correct answers, they don't actually disprove a 'real' frame.)

I would be interested to read it, or even a well made argument to that end.
,

[Twiglet]

I said earlier that I'd seen a flaw in my own argument, that probably invalidated my conclusion. Since nobody else spotted it, here it is:

I wrote 'Now introduce one more particle, and it's travelling towards the first one at 100,000 kps so it's velocity is along the X axis. Now you have a problem. If you choose a frame for the original particle that is moving along the X axis towards the second particle and it's velocity is more than 200,000 kps, then the second particle is travelling in that frame at more than 300,000 kps, or more than the speed of light.'

That's where the flaw crept in. The second particle travels towards the first one at 100,000 kps. BUT ONLY IN ONE FRAME! For any other reference frame, time dilation will alter the 100,000 quantity.
So if you want to stick to the 100,000 figure, then for any other frame, you are actually dealing with DIFFERENT PARTICLES. Either way, the conclusion doesn't stand.

On the claim I made, that there IS one real reference frame, that everything moves relative to, then this clearly isn't proved.
But I've yet to see it disproved. When you read about SR, you are always told that every inertial reference frame works equally well, and is equally valid, and that there is no 'real' or 'favoured' frame.
I concede the 'works-equally-well' bit, but not the other. If there was one 'real' reference frame, nothing would change. You can convert from any chosen frame to that one, just as you can to any other. So the convertability of frames does not in itself rule out a single 'real' frame.
I haven't seen any proof, or any mention of a proof, that there is no favoured frame. I've seen it claimed many times, but never seen any reason as to why.
The fact that the speed of light is independent of the motion of the source, and always the same figure, surely points to it being a charcteristic of an enabling medium of some sort, even if it doesn't conform to what we think of as a material medium.

Does anyone have a reference for a proof that there is no 'real' frame? ( The Lorenz transformations simply prove that you can 'consider' particles as moving in different frames, and get correct answers, they don't actually disprove a 'real' frame.)

I would be interested to read it, or even a well made argument to that end.
,

Historically, people did believe in an absolute frame of reference. The idea is considered obselete because no evidence supports it, and it isn't needed to explain anything relativity doesn't. Go have a look for yourself.

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

[mistermack]

Historically, people did believe in an absolute frame of reference. The idea is considered obselete because no evidence supports it, and it isn't needed to explain anything relativity doesn't. Go have a look for yourself.

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

An absolute frame of reference is obviously just as hard to disprove as to prove. Otherwise it would clearly have been done by now, considering all the mental work that has gone into it, by the top physicists of the day.
However, as you say, it's not needed. It's the coincidence of the speed of light being the speed of our information that makes every frame 'valid' in my view.
( that's what I was pushing in argument 2 of that piece ).

The Einstein quote calling empty space equipped with gravitational and electromagnetic fields the "aether", is really along the lines that I was thinking.
The early ideas of aethers were all based on a kind of fluid that you passed through, rather than an entity in which you were some kind of disturbance.

I still feel that absolute is the fact, and relativity is just a lucky bonus that makes all the calculations easier.
.

[Farsight]

Historically, people did believe in an absolute frame of reference. The idea is considered obsolete because no evidence supports it..

This simply isn't true. See the CMBR dipole anisotropy. The Cosmic Microwave Background Radiation provides a very real mechanism for determining motion through the universe, and the buck stops with the universe. This is a de-facto absolute frame of reference. Also see Einstein's Leyden Address where he says: "according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether".

Mistermack: don't listen to Twiglet, he's promoting ignorance and myth out of some old textbook that's way out of date.

[ChildInAZoo]

The CMB doesn't provide an absolute frame of reference because, as we know from numerous observations, the fundamental physics of any system doesn't care in the slightest about its orientation relative to the CMB. We even use this feature of physical systems to make detailed observations about the background radiation because we can identify that not all the photons of the CMB were released from the same rest frame.

And, please, "see Einstein's Leyden Address." In it he dismisses the very idea of thinking of an aether as anything like an absolute reference frame.

[MrFungus420]

I earlier said that I realised that no-one commenting on this thread understands SR, and I include you and me in that.

If you don't understand it, how can you have found a problem with it?

Keep basking in that ignorance.

[MrFungus420]

Colubridae, my motto is '' don't mock what you don't understand ''. You seem to do the opposite. Mock everything and understand very little. Perhaps you can clearly explain what's ludicrous? I doubt that you have the nerve to try. Perhaps you could get a teacher to do it for you.
.

Hmmmm...from the first page of this thread:

Colubridae, as usual, your argument contains no flaws.

[mistermack]

We even use this feature of physical systems to make detailed observations about the background radiation because we can identify that not all the photons of the CMB were released from the same rest frame.

I don't get exactly what that means. I thought SR mean't that the photons are considered to be released from EVERY POSSIBLE rest frame simultaneously, and no frame is special, so how is it possible to identify that they were released from this one or that?
.

[Farsight]

Rest frames don't actually "exist", they're an artefact of measurement. The CMBR photons weren't emitted from a rest frame, they were emitted by interactions, and their wavelengths vary like this distribution:



They were scattering around in an "opaque" universe which "cleared" about 400,000 years after the big bang. They call this the "surface of last scattering", but it's not a literal surface. See http://en.wikipedia.org/wiki/Cosmic_mic ... _radiation and especially this paragraph:

The color temperature of the photons has continued to diminish ever since; now down to 2.725 K, their temperature will continue to drop as the universe expands. According to the Big Bang model, the radiation from the sky we measure today comes from a spherical surface called the surface of last scattering. This represents the collection of spots in space at which the decoupling event is believed to have occurred, less than 400,000 years after the Big Bang, and at a point in time such that the photons from that distance have just reached observers.

Also see http://en.wikipedia.org/wiki/Cosmic_mic ... anisotropy which describes how we're moving at circa 627 km/s relative to the CMB rest frame:

CMBR dipole anisotropy
From the CMB data it is seen that our local group of galaxies (the galactic cluster that includes the Solar System's Milky Way Galaxy) appears to be moving at 627±22 km/s relative to the reference frame of the CMB (also called the CMB rest frame) in the direction of galactic longitude l = 276±3°, b = 30±3°. This motion results in an anisotropy of the data (CMB appearing slightly warmer in the direction of movement than in the opposite direction). The standard interpretation of this temperature variation is a simple velocity redshift and blueshift due to motion relative to the CMB, but alternative cosmological models can explain some fraction of the observed dipole temperature distribution in the CMB.

[ChildInAZoo]

We even use this feature of physical systems to make detailed observations about the background radiation because we can identify that not all the photons of the CMB were released from the same rest frame.

I don't get exactly what that means. I thought SR mean't that the photons are considered to be released from EVERY POSSIBLE rest frame simultaneously, and no frame is special, so how is it possible to identify that they were released from this one or that?
.

When we look at photons, we can see in them a difference in their frequency relative to a given frequency. If we expect that a photon emitted from a process in its rest frame should have a specific frequency, we can look at the actual frequency of the photon in a measurement rest frame to tell the relative difference between the measurement rest frame and the rest frame of the process that emitted the photon.

[ChildInAZoo]

Rest frames don't actually "exist", they're an artefact of measurement.

This is backwards. Rest frames do not actually exist, they are a pre-requisite of measurement. If we want to make a measurement, we must first identify a system of coordinates in which to make that measurement.

The CMBR photons weren't emitted from a rest frame, they were emitted by interactions, and their wavelengths vary like this distribution:

The processes that emitted these photons can be considered to have occurred in any frame we wish. For each process, there is a natural frame that we can identify as the rest frame for that process. This frame is identified regardless of the rest frame we might identify for another process. Not all the photons of the CMB come from processes that share the same rest frame. Some come from areas that are moving toward us or away from us, primarily because of the action of gravitation.

A really, really good overview of the CMB and its history is in Peebles, P. James E., Lyman A. Page Jr, and R. Bruce Partridge. 2009. Finding the Big
Bang. 1st ed. Cambridge University Press.

They were scattering around in an "opaque" universe which "cleared" about 400,000 years after the big bang. They call this the "surface of last scattering", but it's not a literal surface.

Well, it actually is a literal surface. It is basically a 2D object.

CMBR dipole anisotropy
From the CMB data it is seen that our local group of galaxies (the galactic cluster that includes the Solar System's Milky Way Galaxy) appears to be moving at 627±22 km/s relative to the reference frame of the CMB (also called the CMB rest frame) in the direction of galactic longitude l = 276±3°, b = 30±3°. This motion results in an anisotropy of the data (CMB appearing slightly warmer in the direction of movement than in the opposite direction). The standard interpretation of this temperature variation is a simple velocity redshift and blueshift due to motion relative to the CMB, but alternative cosmological models can explain some fraction of the observed dipole temperature distribution in the CMB.

The science that forms the basis of this inference also forms the basis of the inference that our sun is oblate relative to the CMB. If the CMB picks out the "real" universe, then our sun, and the Earth, is "really" flattened.

[Farsight]

When we look at photons, we can see in them a difference in their frequency relative to a given frequency. If we expect that a photon emitted from a process in its rest frame should have a specific frequency, we can look at the actual frequency of the photon in a measurement rest frame to tell the relative difference between the measurement rest frame and the rest frame of the process that emitted the photon.

No problem.

Rest frames don't actually "exist", they're an artefact of measurement.

This is backwards. Rest frames do not actually exist, they are a pre-requisite of measurement. If we want to make a measurement, we must first identify a system of coordinates in which to make that measurement.

You're nitpicking. The system of coordinates is an artefact of measurement too.

The processes that emitted these photons can be considered to have occurred in any frame we wish. For each process, there is a natural frame that we can identify as the rest frame for that process. This frame is identified regardless of the rest frame we might identify for another process. Not all the photons of the CMB come from processes that share the same rest frame. Some come from areas that are moving toward us or away from us...

No problem.

...primarily because of the action of gravitation.

How so?

A really, really good overview of the CMB and its history is in Peebles, P. James E., Lyman A. Page Jr, and R. Bruce Partridge. 2009. Finding the Big Bang. 1st ed. Cambridge University Press.

Looks good. Shame it's so expensive: http://www.amazon.co.uk/Finding-Big-Ban ... 0521519829.

Well, it actually is a literal surface. It is basically a 2D object.

I'm afraid it isn't. Have a look at http://nedwww.ipac.caltech.edu/level5/G ... y_lss.html:

"When the Universe cools down below a critical temperature, the fog clears instantaneously everywhere. But you would not be able to see that it has cleared everywhere because, as you look into the far distance, you would be seeing into the opaque past of distant parts of the Universe. As the Universe continues to expand and cool you would be able to see farther, but you would always see the bright opaque fog in the distance, in the past. That bright fog is the surface of last scattering. It is the boundary between a transparent and an opaque universe and you can still see it today, 15 billion years later."

The science that forms the basis of this inference also forms the basis of the inference that our sun is oblate relative to the CMB. If the CMB picks out the "real" universe, then our sun, and the Earth, is "really" flattened.

That's wrong. Length contraction is another observer effect. If you pass me at a very high speed, we see each other as length-contracted from say 2m down to 1m. But we can't scoop each other with our 1m butterfly nets. The reality is that you're "smeared out". You can't detect this locally, and instead you see non-smeared-out objects like me as length-contracted. The situation is symmetrical because motion is relative. If we have no external references, we can't say that it's me moving or you. But in the real universe, with the CMBR, we can.

Sorry if that was a bit of a digression mistermack.

[ChildInAZoo]

You're nitpicking. The system of coordinates is an artefact of measurement too.

Again you do not understand. A system of coordinates is a reference frame. And we cannot have a measurement of length or duration without first specifying a system of coordinates.

...primarily because of the action of gravitation.

How so?

Because of the clumpng of matter. For more details, see a textbook on the subject.

Well, it actually is a literal surface. It is basically a 2D object.

I'm afraid it isn't. Have a look at http://nedwww.ipac.caltech.edu/level5/G ... y_lss.html:

"When the Universe cools down below a critical temperature, the fog clears instantaneously everywhere. But you would not be able to see that it has cleared everywhere because, as you look into the far distance, you would be seeing into the opaque past of distant parts of the Universe. As the Universe continues to expand and cool you would be able to see farther, but you would always see the bright opaque fog in the distance, in the past. That bright fog is the surface of last scattering. It is the boundary between a transparent and an opaque universe and you can still see it today, 15 billion years later."

You need to read more carefully and think about what you are reading. That the "surface" is a 2D object is right there in what you have cut-and-pasted.

The science that forms the basis of this inference also forms the basis of the inference that our sun is oblate relative to the CMB. If the CMB picks out the "real" universe, then our sun, and the Earth, is "really" flattened.

That's wrong. Length contraction is another observer effect. If you pass me at a very high speed, we see each other as length-contracted from say 2m down to 1m. But we can't scoop each other with our 1m butterfly nets. The reality is that you're "smeared out". You can't detect this locally, and instead you see non-smeared-out objects like me as length-contracted. The situation is symmetrical because motion is relative. If we have no external references, we can't say that it's me moving or you. But in the real universe, with the CMBR, we can.

Again, you don't understand the science. There is nothing more to say here on this subject.