Is Relativity Reality?

[Farsight]

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.

I do understand. You don't. You think an abstract thing like a reference frame or a coordinate system actually exists. It doesn't. Care to dispute that? Would you like to point one out in the clear night sky?

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

LOL. Slippery. You said "Some come from areas that are moving toward us or away from us". Doesn't square too well with the surface of last scattering does it?

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.

Ah, let's see now:

"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."

Uh huh. The fog clears instantaneously everywhere. It isn't a literal surface. Capiche?

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

Apart from you don't have a clue about relativity or particle physics.

[ChildInAZoo]

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.

I do understand. You don't. You think an abstract thing like a reference frame or a coordinate system actually exists. It doesn't. Care to dispute that? Would you like to point one out in the clear night sky?

How bad at reading are you? Do you actually have a learning disorder? I just said that systems of coordinates do not really exist. I did point out that they were prerequisites for measurements, however. Measurements are also abstract entities.

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

LOL. Slippery. You said "Some come from areas that are moving toward us or away from us". Doesn't square too well with the surface of last scattering does it?

Yes it does. Because we are seeing light from a particular "moment", from particular physical systems that are in motion and that have slightly different properties. Again, you can learn this from simply doing a little reading of the actual science--this stuff on anisotropy in the CMB has been in the works since the 1970s.

Uh huh. The fog clears instantaneously everywhere. It isn't a literal surface. Capiche?

Again, you do not understand and you are so close. Run time backwards to the surface and track the light that we are watching right now. To what does it return?

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

Apart from you don't have a clue about relativity or particle physics.

Yes, because according to you being able to follow the mathematics automatically prevents me from understanding.

[Farsight]

How bad at reading are you? Do you actually have a learning disorder? I just said that systems of coordinates do not really exist. I did point out that they were prerequisites for measurements, however. Measurements are also abstract entities.

I'm very good at reading. Let's see now, I said:

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

And you replied:

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.

Then I said:

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

And you said:

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.

I understand all right. And I've forced you to concede that the things you talk about when dismissing mistermack so arrogantly aren't real things, including the surface of last scattering. The universe cleared instantaneously, it doesn't contain a literal surface. Now let mistermack get on, and this time try some sincerity when you respond to him.

[ChildInAZoo]

Your reply lacks sufficient foundational quality. I must advise the author to submit his reply somewhere else.

[mistermack]

I have no idea if the frame of reference provided by the CMB is the one that I'm claiming to exist. I would like to point to argument 2, in my original post, for the inconsistencies in SR.
http://kevinmcalpine1.pwp.blueyonder.co ... nt%202.htm

Why do I think that there is just one 'real' frame of reference?
Well, firstly, if there was, nothing would change. SR would still give correct results to calculations. If you can transform all physical properties to any other frame, then obviously you can do that to my ' one single ' valid frame.
Nobody has ever proved that there is NOT a single valid frame.

Why do I think that there is?
1) The widely accepted idea of spacetime, rather than 'nothing' occupying space.
Einstein likened this to an ether. Except that we should abandon all of the properties that we usually assign to an ether. The last one that we should abandon is any form of motion. So the spacetime ether fills space, but doesn't move. Sounds like a frame of reference to me.
2) The fact that the speed of light is always the same, irrespective of the velocity of the matter that emits it. Just like the speed of sound in air being a property of the air. But unlike air, spacetime doesn't blow about, so the speed of light never varies.
So if space is filled with spacetime, that never moves, this indicates one single valid frame of reference to me. All other frames simply give correct answers to physical calculations because time dilation exactly corrects the anomalies.
It's a huge bonus, in that we can use any frame of reference to make calculations, so we can use our own, even though we know we are hurtling through space around the milky way, and around the sun, and spinning on the earth, all at the same time.

So why should I be bothered? I just don't like the contradictions in SR. People seem to have made the jump from a perfectly good way of way of measuring and calculating what is happening, to declaring that SR IS what's happening, and that there is no ''reality'' as we know it.

Just because we don't have the tools to observe ''reality'', I don't think that's good enough reason to abandon it.

If you look at a galaxy one billion light years distant, you cannot see it as it is now, only how it was a billion years ago. And if you sent a message, it wouldn't get there for a billion years. So we can never interract with that galaxy. But that's no reason to say that what we experience of that galaxy IS reality. We know that somewhere in space is that galaxy, a billion years older, even though we don't have the tools to see it as it actually is.

To me, relativity is like that. It's what we experience, because we have information that travels at the same speed as light, and time that slows with velocity. But out there, there is a reality, independent of this.
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[ChildInAZoo]

Look, you really, really should learn special relativity. This is a prerequisite to criticizing it. As it stands, you are attacking some kind of crazy theory that nobody believes in.

[mistermack]

Look, you really, really should learn special relativity. This is a prerequisite to criticizing it. As it stands, you are attacking some kind of crazy theory that nobody believes in.

No offence, childinazoo, but that goes for you too. And this time, try to understand it, rather than just memorising it. It's much harder, but you might find it worthwhile.
The you could start making some comments that were actually worth reading.
.

[ChildInAZoo]

Well, my understanding was enough to get me through my grad classes and my dissertation, so I'm happy enough with it. Substantive comments, however, are wasted on you since you clearly do not care for them. The "problem" that you discovered in your own argument seems like a mishmash of the specific criticisms I offered.

[mistermack]

Well, my understanding was enough to get me through my grad classes and my dissertation, so I'm happy enough with it.

That's good. I'm pleased, there's hope for my parrot then.
Strange it didn't help you solve a simple problem, or make a relevant comment now and then.

[Farsight]

I think you've got it mistermack. Space isn't nothing. Have a read of The Other meaning of Special Relativity by Robert Close. This doesn't invalidate special relativity, it's just explains it, and delivers understanding. But sadly there are some people who seem absolutely opposed to understanding, and the open discussion that promotes it.

[lpetrich]

Why do I think that there is just one 'real' frame of reference?
Well, firstly, if there was, nothing would change. SR would still give correct results to calculations. If you can transform all physical properties to any other frame, then obviously you can do that to my ' one single ' valid frame.
Nobody has ever proved that there is NOT a single valid frame.

Without the detection of preferred-frame effects, it is a meaningless hypothesis.

Consider position and direction in 3-space. Is there a primary cosmic reference point? A primary cosmic triplet of directions? It seems almost self-evident that there is no such point and that there are no such directions. That is, that the laws of physics are independent of space shifts and rotations.

A similar sort of relativity regarding space and time is an important part of both Newtonian and Einsteinian mechanics, as it may be called. In both of them, there is no primary cosmic zero time and no primary cosmic velocity. That is, the laws of physics are independent of time shifts and boosts.
Newton -- Galilean boosts:
t' = t
x' = x - v*t
Einstein -- Lorentz boosts:
t' = (t - v*x/c2)*(1 - (v/c)2)-1/2
x' = (x - v*t)*(1 - (v/c)2)-1/2
Boosts are sort of like rotations between space and time.

Each of these transformations has a conserved quantity associated with it:
Space shift - linear momentum
Rotation - angular momentum
Time shift - energy
Boost - center-of-mass position

Why do I think that there is?
1) The widely accepted idea of spacetime, rather than 'nothing' occupying space.
Einstein likened this to an ether. Except that we should abandon all of the properties that we usually assign to an ether. The last one that we should abandon is any form of motion. So the spacetime ether fills space, but doesn't move. Sounds like a frame of reference to me.

Spacetime does not fill space, because it contains space.

2) The fact that the speed of light is always the same, irrespective of the velocity of the matter that emits it. Just like the speed of sound in air being a property of the air. But unlike air, spacetime doesn't blow about, so the speed of light never varies.

The speed of light in a vacuum is constant because of the geometry of space-time. Space and time are subject to a generalization of Pythagoras's theorem:
ds2 = dx12 + dx22 + dx32 - c2dt2

where d(variable) is the difference in its value between two points. It's easy to show that it's invariant under space shifts, space rotations, time shifts, and Lorentz boosts.
ds2 > 0 -- spacelike
ds2 < 0 -- timelike
ds2 = 0 -- lightlike or null
Timelike and lightlike intervals also have well-defined time directions.

mistermack, you have to be careful to avoid projecting Newtonian and pre-Newtonian intuitions onto relativity.

[colubridae]

Why do I think that there is just one 'real' frame of reference?
Well, firstly, if there was, nothing would change. SR would still give correct results to calculations. If you can transform all physical properties to any other frame, then obviously you can do that to my ' one single ' valid frame.
Nobody has ever proved that there is NOT a single valid frame.

Without the detection of preferred-frame effects, it is a meaningless hypothesis.

Consider position and direction in 3-space. Is there a primary cosmic reference point? A primary cosmic triplet of directions? It seems almost self-evident that there is no such point and that there are no such directions. That is, that the laws of physics are independent of space shifts and rotations.

A similar sort of relativity regarding space and time is an important part of both Newtonian and Einsteinian mechanics, as it may be called. In both of them, there is no primary cosmic zero time and no primary cosmic velocity. That is, the laws of physics are independent of time shifts and boosts.
Newton -- Galilean boosts:
t' = t
x' = x - v*t
Einstein -- Lorentz boosts:
t' = (t - v*x/c2)*(1 - (v/c)2)-1/2
x' = (x - v*t)*(1 - (v/c)2)-1/2
Boosts are sort of like rotations between space and time.

Each of these transformations has a conserved quantity associated with it:
Space shift - linear momentum
Rotation - angular momentum
Time shift - energy
Boost - center-of-mass position

Why do I think that there is?
1) The widely accepted idea of spacetime, rather than 'nothing' occupying space.
Einstein likened this to an ether. Except that we should abandon all of the properties that we usually assign to an ether. The last one that we should abandon is any form of motion. So the spacetime ether fills space, but doesn't move. Sounds like a frame of reference to me.

Spacetime does not fill space, because it contains space.

2) The fact that the speed of light is always the same, irrespective of the velocity of the matter that emits it. Just like the speed of sound in air being a property of the air. But unlike air, spacetime doesn't blow about, so the speed of light never varies.

The speed of light in a vacuum is constant because of the geometry of space-time. Space and time are subject to a generalization of Pythagoras's theorem:
ds2 = dx12 + dx22 + dx32 - c2dt2

where d(variable) is the difference in its value between two points. It's easy to show that it's invariant under space shifts, space rotations, time shifts, and Lorentz boosts.
ds2 > 0 -- spacelike
ds2 < 0 -- timelike
ds2 = 0 -- lightlike or null
Timelike and lightlike intervals also have well-defined time directions.

mistermack, you have to be careful to avoid projecting Newtonian and pre-Newtonian intuitions onto relativity.

for the 458 time of saying.

[mistermack]

Without the detection of preferred-frame effects, it is a meaningless hypothesis.

I can go with that. Although I would say, undemonstrated, or undemonstrable, would be fairer.
Evolution was a 'meaningless hypothesis', before they found the fossils.

Spacetime does not fill space, because it contains space.

Fair engough, but I'm sure you knew what I meant.

The speed of light in a vacuum is constant because of the geometry of space-time.

Nothing to do with the fact that time and distance are defined by the movement of energy?

Now you know very well that SR only works, because of the time dilation effect. If time was totally unaffected by motion, it would fall apart. How many valid frames of reference would we be left with?
Perhaps you can work that out.

I'm not pushing or endorsing any of farsight's opinions, but I've read a bit of the document he just linked to, by Robert Close.
The part I found particularly interesting was the analysis of the submarines. If their clocks were made using soundwaves in water, you would get the same kind of time dilation for a moving clock, and all frames would be valid, using Lorenz transformations.
So I think I do agree with his proposal that SR is a feature of our measurement tools, and not intrinsic to spactime itself. It's roughly what I've been saying.

If you click that link I gave to argument 2, I'm making a similar sort of point. ( if a new kind of light was discovered, whose speed was infinite, as far as we could tell, and we could use it in our measurements, and make clocks with it that didn't experience time dilation, would SR still stand? )
And which light, and which clocks, would you say gave a true picture of reality?

Don't get me wrong, I'm not saying we should change anything, I'm just saying that what we experience as reality is down to the freak effects of local time dilation, and our information being transimitted at exactly the same speed as light.

Nobody has answered my earlier question yet. Time can slow, almost to a stop, with velocity. How does it work the other way? Is there a limit on how fast a clock can run? If we send a clock up in a rocket, and accelerate it to half the speed of light, it actually runs slow. Slow it down, it actually speeds up. But slow it down relative to what frame of reference? Is there a limit to how much it can speed up?
.

[lpetrich]

Without the detection of preferred-frame effects, it is a meaningless hypothesis.

I can go with that. Although I would say, undemonstrated, or undemonstrable, would be fairer.
Evolution was a 'meaningless hypothesis', before they found the fossils.

Except that much of the case for it was non-fossil: comparative anatomy and biogeography.

The speed of light in a vacuum is constant because of the geometry of space-time.

Nothing to do with the fact that time and distance are defined by the movement of energy?

Absolutely nothing -- time and space aren't even defined by the "movement of energy".

I'm not pushing or endorsing any of farsight's opinions, but I've read a bit of the document he just linked to, by Robert Close.
The part I found particularly interesting was the analysis of the submarines. If their clocks were made using soundwaves in water, you would get the same kind of time dilation for a moving clock, and all frames would be valid, using Lorenz transformations.

Except that constancy of the speed of sound is relative to its medium, and the speed of light in a vacuum is constant because of the geometry of space-time.

So I think I do agree with his proposal that SR is a feature of our measurement tools, and not intrinsic to spactime itself. It's roughly what I've been saying.

But different tools don't produce different effects.

If you click that link I gave to argument 2, I'm making a similar sort of point. ( if a new kind of light was discovered, whose speed was infinite, as far as we could tell, and we could use it in our measurements, and make clocks with it that didn't experience time dilation, would SR still stand? )
And which light, and which clocks, would you say gave a true picture of reality?

It's not light itself that's the key, it's the geometry of space-time.

Such infinite-speed particles would be tachyons, and these particles would travel only be infinite speed in certain coordinate frames, just as slower-than-light particles travel at zero speed only in certain coordinate frames.

[mistermack]

Except that much of the case for it was non-fossil: comparative anatomy and biogeography.

That's right. There was a good CASE for it, but no evidence till the fossils.

Absolutely nothing -- time and space aren't even defined by the "movement of energy".

We'll have to disagree on that. ( I said time and distance by the way) If all that existed was fields, with no disturbances happening, time and distance would be meaningless.

Except that constancy of the speed of sound is relative to its medium, and the speed of light in a vacuum is constant because of the geometry of space-time.

Which is arrived at using the speed of light as a constant.

But different tools don't produce different effects.

Clocks made from sound waves in water, and information carried at the speed of sound in water, give an SR effect in water. But with our usual clocks, and using light, that SR effect vanishes.

Such infinite-speed particles would be tachyons, and these particles would travel only be infinite speed in certain coordinate frames, just as slower-than-light particles travel at zero speed only in certain coordinate frames.

No, infinite would be infinite in any frame. ( not that infinity can actually exist ).
That's why I wrote "as far as we could tell".
I just mean, no discernible delay in information, and no measureable time dilation.
It's a "what if", that's all. But it's a valid point to make.
If we had these tools, we would be able to see that SR was not what is actually happening.
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