Relativity Discussion Thread

[Sam5]

Good one, Sam5.

Thanks.

Hmm, there were different editions of both Optics and the Principia.

The Question 20 in the 1704 Edition is not the same as what that guys says is in the 1706 Edition.

I think the apparent discrepancy lies in the difference between the terms “medium” and “matter”.

The term “the fictitious matter” in the 1706 Edition suggests a physical substance such as a thin gas or vapour, and this is what Newton was objecting to in that Edition.

However, the term “the Aetherial Medium” referred to in the 1704 Edition is not made up of physical “matter”. This “Aetherial Medium” is generated by the physical matter of the astronomical bodies, and he is saying the “medium” fills the space in-between the bodies. That is, the “medium” is essentially the gravity “fields” of space, but at that time (1704) the term “field” had not yet been invented, so in its place Newton used the term "Atherial Medium”.

These two words, “medium” and “matter”, are very tricky when used in terms of the “ether”, and in some early science publications they seem to be used almost interchangeably, even though they are actually quite different.

[daver]

But as milli360 pointed out (at least, I think this was his point), you have to assume that there's no dilation perpendicular to the direction of travel in order to derive the equations that way, don't you?

The way he does it in the 1905 paper actually leads to the conclusion that there's no perpendicular dilation.

If I understand what you're getting at, you can get consistent equations by assuming either a spatial contraction perpendicular to the velocity vector or a time dilation. A thought experiment should be sufficicient to demonstrate that a space contraction doesn't make sense.

[Normandy6644]

But as milli360 pointed out (at least, I think this was his point), you have to assume that there's no dilation perpendicular to the direction of travel in order to derive the equations that way, don't you?

Yep, the method Normandy6644 is talking about, I think, is the same as the one Eroica brought up originally.

SeanF and I do a lot of thinking, because you never know, on the BABB.

I think it is, and yes you do have to make those assumptions. The reason it's still nice to look it is because you can derive the basic equation in a very simple manner. It won't hold up under intense scrutiny, but if someone ever randomly asks you to prove the time dilation equation on a napkin or something (happens all the time, I know), you can do it without too much trouble.

Also, Lorentz derived the transformations, but as has been said, he didn't know why they worked. Minkowski actually explained them the best, allowing Einstein to use his methods to formulate GR.

[Eroica]

This site has links to PDFs of most editions of Newton's works:

The Online Newton Project

Newton's Opticks

[oriel]

Banned poster content deleted

[Kaptain K]

... I expect to be banned from the forum...

Why? Is it because you dropped the "36" from your nickname when you rejoined and expect the BA to figure it out soon?

[Sam5]

Mach: on Newton's Absolute Time

"This absolute time can be measured by comparison with no motion; it
has therefore neither a practical nor a scientific value; and no one
is justified in saying that he knows aught about it. It is an idle
metaphysical conception."
Mach, Analyse der Empfindungen, 6th ed.

Why do you suppose that Mach would compare “absolute time” to “no motion”, since no motion means “no time”? Absolute time is merely “steady motion”, where the gaps in between the motion-related events are all of the same duration, whether we measure time by a linear device, counting the increments in inches, or by means of the usual vibratory method, counting the number of vibrations with the duration in between each vibration cycle being exactly the same as the previous one.

There would be such a thing as "absolute time", if we could find something that moved in a straight line at a steady speed or vibrated or rotated steadily, forever, but apparently nothing in the universe does that.

One problem I see with Newton’s short description of “absolute time” is that it tends to suggest time as an independent entity that sort of “permeates” the universe. Whereas I see time is being strictly a local phenomenon, that transpires only where things move and vibrate. Since there are so many things that move and vibrate, all around us, and at fairly steady rates, this tends to give us the impression that “time itself” permeates the universe, but I say it doesn’t. I say it occurs only when and where things are moving. If we could stop things from moving in a small part of space, then all of “time” in that small part of space would stop.

Newton might have known this, but he just didn’t say it in any of his books, and he seemed to think of time as flowing even without motion, especially when he said:

“Absolute, true, and mathematical time, of itself, and from its own nature flows equably without regard to anything external, and by another name is called duration: relative, apparent, and common time, is some sensible and external (whether accurate or unequable) measure of duration by the means of motion, which is commonly used instead of true time; such as an hour, a day, a month, a year.”

But I disagree. I say motion causes time. Motion generates time. No motion, no time. Steady motion equals steady time. I see time as a product of motion and motion as a product of kinetic energy. Thus, in my view, time starts with energy, energy generates motion, and time is a numerical accumulation of motion-related events, a counting of the events in sequence, and it is localized to the thing that is moving or vibrating. Absolute time would be steady motion or vibration with the same duration in between the events. When motion stops, let’s say within a single mechanical clock, that particular time stops. However, all of time does not stop in the area around the clock, since many other things continue to move and vibrate. In fact, the atoms and molecules inside the clock continue to vibrate and oscillate. Only the time that was being generated by the turning of the hands and the gears stops in the clock. But the rest of time doesn’t stop.

About being banned, just try not to get into any serious personal fights and arguments, and I think everything will be ok.

Uhh, what is your overall point?

[oriel]

Banned poster content deleted

[Normandy6644]

Hey guys, keep in mind this thread is for discussing mainstream relativity as it now stands, not quibbles with the theory. If you want to start debating certain points of it, please go to the Against the Mainstream topic that Tensor started. Thanks.

[oriel]

Banned poster content deleted

[oriel]

Banned poster content deleted

[Kaptain K]

I apologise Sam5 for making a mess of the posting by putting the thing entirely in 'quote',I am new to that feature and unfortunately when posting I was required to resubmit my password.

There is an "edit" button in the top right corner of your post. Click on it and you can correct your errors.

[The Bad Astronomer]

What is it with some people who cannot stay away from here? Sheesh. I have deleted what he wrote, because it's a very bad idea to come back here after being banned and posting something.

[Sam5]

Newton's Absolute Time

Uhh, nevermind.

[Celestial Mechanic]

Darn! I only saw one of He Who Will Not Name Einstein's posts in his new incarnation before the BA deleted them all! Of course, a leopard does not change his spots, so I imagine it was the same old same old about the Equation of Time, the sidereal rotation being a kludge, cosmic modelling, physics being a total wasteland after 1905, etc., etc.

[Kaptain K]

Nope. Just long rambling disertations about Newton. See some of Sam5's responses to HWSNNE for quotes.

[milli360]

This is generally based on Einstein’s deduction in 1911 that the “tick rates” of atomic clocks tend to follow the speed rate changes of light.

Sam5, I was browsing our high school library, and guess what was on the shelves?

Apparently, Einstein wrote up an article in 1912 On the Special Theory of Relativity, and was set to publish it when the first world war, or something, intervened. When they finally got around to it, he'd published his General Theory, and they decided to not publish the 1912 article. It was published in facsimile in 2000. The great thing about it is that he crossed off whole paragraphs throughout the article--but they are included in the new book. Check it out. There are some interesting comments about the speed of light, crossed out.

Here it is at Amazon.com. The editorial review and the customer review seem to assume that it is the original theory article. One of them mentions publication history--I'd have sworn that it said it hadn't been published before this. O well.

[Sam5]

Check it out. There are some interesting comments about the speed of light, crossed out.

Here it is at Amazon.com. The editorial review and the customer review seem to assume that it is the original theory article. One of them mentions publication history--I'd have sworn that it said it hadn't been published before this. O well.

Thanks very much for the information. I’ll try to track down a copy of that book. Apparently Einstein did publish an article in the Annalen der Physik in 1912, modifying the original 1905 SR theory. This is what Max Abraham said in a paper of his that was published in 1912:

“Already before period of one year A. Einstein, by accepting an influence of the gravitation potential on the speed of light, gave up the postulate of the constant speed of light essential for his earlier theory 1); in a work appeared recently 2)......

1) A. Einstein, Ann. d. Phys. 35. p 898. 1911.
2) A. Einstein. Ann. d. Phys. 38. p. 355. u. 443. 1912.”

This type of stuff is what I’ve been investigating. Einstein made a major switch-over from the basic “relativity theory” (the 1905 SR theory), to the GR theory of 1916. This switch-over began in 1911 when he realized his 1905 theory contained errors and when he realized that the speed of light is variable and not “constant”. He actually started examining gravitation and accelerative effects as early as 1906-07, but he didn’t make a major breakthrough until his 1911 gravitational redshift theory.

Why don’t you post some quotes from that book?

[milli360]

Apparently Einstein did publish an article in the Annalen der Physik in 1912, modifying the original 1905 SR theory. This is what Max Abraham said in a paper of his that was published in 1912:

Yes, you've posted that before. That's why I thought you'd be interested. Einstein was on a quest almost from day one--he dallied in quantum mechanics, but returned to the general relativity pursuit.

This type of stuff is what I’ve been investigating. Einstein made a major switch-over from the basic “relativity theory” (the 1905 SR theory), to the GR theory of 1916.

Of course. No one denies that.

This switch-over began in 1911 when he realized his 1905 theory contained errors and when he realized that the speed of light is variable and not “constant”.

I disagree. There is a constant trend throughout his works, it appears to me. It's like going from learning to catch fish from the river, to learning to catch different fish from different parts of the river. It's unfair to characterize it as an error, when there is no evidence for that, other than supposition.

He actually started examining gravitation and accelerative effects as early as 1906-07, but he didn’t make a major breakthrough until his 1911 gravitational redshift theory.

I would say he started earlier than that. Too, he was influenced by the philosophy, and physics, of Mach.

Why don’t you post some quotes from that book?

I don't have it. It's a reference book, left in the library.

[Sam5]

I disagree. There is a constant trend throughout his works, it appears to me. It's like going from learning to catch fish from the river, to learning to catch different fish from different parts of the river. It's unfair to characterize it as an error, when there is no evidence for that, other than supposition.

Yes, you are right about the "constant trend". I have Volume 2 of the “Collected Papers”, and I’m surprised by how many “atomic” papers he wrote. He was quite an expert on the inner workings of atoms, and in fact he was fairly well known in theoretical physics before he wrote the first 1905 relativity paper. Volume 2 contains some of his earliest attempts to add “acceleration” to his basic first relativity theory.

I think he did not include acceleration in the first theory because he imagined the “stationary system” to be the surface of the earth, as in the Michelson Morley experiment, and so he wanted to consider a steady relative speed and velocity before he began to inquire about the effects of acceleration. He made several interesting attempts in 1907 and ’09, but he kept getting some of the SR principles mixed up with some of the newly emerging GR principles. The two are not compatible. This is why he said in his 1911 paper:

”To avoid unnecessary complications, let us for the present disregard the theory of relativity, and regard both systems from the customary point of view of kinematics, and the movements occurring in them from that of ordinary mechanics.”

He had to actually start over by leaving out some of the incorrect principles of the 1905 paper. In the 1911 paper, he returned to some of the original relativity ideas that Lorentz had proposed in his 1895 book. By 1911 Einstein realized that “fields” and “acceleration” must be considered in a true relativity theory, and they can not be left out, as they were in his first 1905 relativity paper.

Based on what I’ve read, he actually started his “relativity” thinking as far back as his high school years, and that 1895 Lorentz book influenced him quite a lot. He apparently worked on his first relativity theory for years, long before he first published it in 1905. However, as he began to consider fields and acceleration more an more, he gradually began to realize the 1905 theory contained errors. He finally officially split the theories into two different versions, when, in 1916, he called the first theory, the one without fields and acceleration the “special” theory, and the ones in which he did consider fields and acceleration, he included them in his “general” theory.

So, the 1911 paper fits into the “general” theory, even though he was still calling all his relativity papers “the relativity theory” in 1911. But after 1916, the 1911 paper became classified under the General theory heading. That is why his statement about “the velocity of propagation of light varies with position” is included in the General relativity section of his 1916 book, and not with his earlier Special relativity section. This statement comes right out of his 1911 paper, so the 1911 paper is part of the General theory, not the Special theory.

Regarding whether or not we should call the 1905 mistakes “errors” or not, well I think we should and I’m positive that he realized they were errors. That’s why he had to change and alter the 1905 theory several times between 1907 and 1918. But he never wanted to call them “errors” in any public writings, and I think that’s because he was quite angry at some of the guys who were his most vocal critics. There were political reasons for this, and I’m not sure I blame him for what he did. At the time, I might have done the same thing, considering the hostile climate under which he worked in Europe, around the time of WW I.

Just because there has been a hundred-year tradition of not calling the SR errors “errors”, I don’t see any reason to continue that tradition, since they really were errors and Einstein realized they were errors. What we’ve got now, that most people during the past 100 years did not have, are good English translations of most of his work, so now we can objectively look back and examine this full situation in light of its historical context. And I find it absolutely fascinating. I think it would make a great movie. This involves far more than just physics. It deeply involves the politics of that era too, and those politics continued to intensify right on through the 1920s, the ‘30s, and the 1940s.

[Jobe]

omg he's still going

[Normandy6644]

As I have said numerous times, if you want to debaterelativity, do it here. If you want to discuss relativity, do it here. Note the difference.

[Sam5]

As I have said numerous times, if you want to debaterelativity, do it here. If you want to discuss relativity, do it here. Note the difference.

Milli and I have been discussing relativity, both on the board and in PMs. He posted two messages to me on this thread, and I responded to them. Isn’t that what this thread is for?

There are a lot of old Einstein papers that were never translated into English until just recently. Some of these newly-translated papers contain changes and transitions of his opinions from his original SR attitude to his more advanced and complex GR attitude, and Milli and I have been discussing that. It is a very interesting subject. We generally do our debating in PMs.

[milli360]

Volume 2 contains some of his earliest attempts to add “acceleration” to his basic first relativity theory.

Yes, very early. As I've mentioned before, I consider it to have been done in the original 1905 paper.

I think he did not include acceleration in the first theory because he imagined the “stationary system” to be the surface of the earth, as in the Michelson Morley experiment, and so he wanted to consider a steady relative speed and velocity before he began to inquire about the effects of acceleration.

A more reasonable approach would be to assume that he was just trying to extend Galilean relativity. In retrospect, that would be a good first step, wouldn't it? Plus, that is the reasoning given in the history books.

Based on what I’ve read, he actually started his “relativity” thinking as far back as his high school years, and that 1895 Lorentz book influenced him quite a lot. He apparently worked on his first relativity theory for years, long before he first published it in 1905.

They don't spring instantly from one's mind fully formed, that's for sure.

However, as he began to consider fields and acceleration more an more, he gradually began to realize the 1905 theory contained errors.

You insist on calling them errors, when they don't appear that way, to me.

Regarding whether or not we should call the 1905 mistakes “errors” or not, well I think we should and I’m positive that he realized they were errors. That’s why he had to change and alter the 1905 theory several times between 1907 and 1918. But he never wanted to call them “errors” in any public writings, and I think that’s because he was quite angry at some of the guys who were his most vocal critics. There were political reasons for this, and I’m not sure I blame him for what he did. At the time, I might have done the same thing, considering the hostile climate under which he worked in Europe, around the time of WW I.

Part of the problem with calling them "errors" is that the things which you have called errors, over the last four years, are not errors but only misunderstandings on your part. Clearly, the theory evolved, and things changed as new ideas developed. To call the early things errors is valid--except the that the things that you identify specifically as errors are not errors.

Just because there has been a hundred-year tradition of not calling the SR errors “errors”, I don’t see any reason to continue that tradition, since they really were errors and Einstein realized they were errors.

I fall into many discussions where people disagree with me that Newton has been shown to be wrong. It all boils down to point of view. Is Newton wrong? Yes. Is Newton's theory still useful? Yes--but then how can it be wrong?

But disagreement that I have with you is that you try to say that a specific line of logic is in error, or a particular equation, or a paragraph--and I disagree, when I think that you are wrong.

Of course it would make a great movie, I even enjoyed IQ.

As I have said numerous times, if you want to debaterelativity, do it here. If you want to discuss relativity, do it here. Note the difference.

That other thread seems to have run out of steam. As near as I can tell, Sam5 was criticized for one of his statements about relativity, but it turned out the statement was compatible with relativity, and not against the mainstream. Sam5 feels that his interpretation is mainstream relativity--if he makes a comment that you feel is outside the mainstream, take it to that thread, and we can discuss it.

Where would be appropriate to dicsuss the hsitory of relativity? Against the Mainstream, or GA? Or BABBling?

[Sam5]

That other thread seems to have run out of steam. As near as I can tell, Sam5 was criticized for one of his statements about relativity, but it turned out the statement was compatible with relativity, and not against the mainstream. Sam5 feels that his interpretation is mainstream relativity--if he makes a comment that you feel is outside the mainstream, take it to that thread, and we can discuss it.

Where would be appropriate to dicsuss the hsitory of relativity? Against the Mainstream, or GA? Or BABBling?

Yes, that is what we are discussing now, the history. I think you and I have finally gone beyond arguing about SR “time dilation” stuff.

What happened was that he made the errors in 1905 because he was trying to “correct” the 1895 Lorentz book by removing the “ether” from it, but in that process Einstein also left out very important things that Lorentz had included in the original theory, i.e. fields, acceleration, and real physical forces. Leaving out this stuff leads to paradoxes and errors in the 1905 paper.

He began to realize the errors and the reasons for them by 1911. And in 1918 he corrected them by adding fields, acceleration, atomic clocks, and real physical forces to the original 1905 paper. You need to study the original Lorentz theory, and many of Einstein’s papers in which he included gradual changes to the original 1905 paper. The history books usually don’t go into that much detail about the changes and why he made them, and they almost never discuss the original 1895 Lorentz book that started modern “relativity” theory in the first place. Very few people today have read the 1895 Lorentz book or the 1918 Einstein paper. These two works clear up a lot of the mystery.

What tends to “work” in SR, is actually the Lorentz parts of it. That is, if you add back the fields, the acceleration, and the real physical forces, and apply them to specifically atomic clocks (but not to mechanical clocks) then part of the theory works without paradoxes. But the original “relative motion” part does not work, since just “relative motion” doesn’t do anything or place any “forces” on anything. So, add the Lorentz stuff back to the SR theory, and what you have is the Lorentz theory. SR itself disappears when the fields, acceleration, atomic clocks, and real “forces” are added to it.

[Kaptain K]

omg he's still going

What he said! :roll:

[Sam5]

Where would be appropriate to dicsuss the hsitory of relativity? Against the Mainstream, or GA? Or BABBling?

Hey, I’ve got an idea. Suppose you do this.... suppose you start a “relativity history” thread in this forum, and we can post on that, while these other guys can talk on this thread about their favorite topics and points of view. Anyone who wants to talk about the history and the gradual changes and the differences between Lorentz theory, SR theory, and GR theory, and what we might think of as the “errors” of the various theories, can do that on the other thread, and these guys can have their thread where they can have their own thread, so we won’t over-lap each other or irritate each other.

[milli360]

Leaving out this stuff leads to paradoxes and errors in the 1905 paper.

Unless you can point to a passage in the literature that says "I made a mistake" or you can point to a math error, then I think you should avoid ascribing motive based upon supposition. You've objected to that before when others have ascribed motive to you, and I don't think it should be done here.

As far as that goes, there is no real paradox, that can be seen in the 1905 paper.

These two works clear up a lot of the mystery.

A calculus book would clear up a lot of the "mystery," too.

But the original “relative motion” part does not work, since just “relative motion” doesn’t do anything or place any “forces” on anything.

As we've discussed before (the "potential box"), the force is not necessary, in GR.

[Sam5]

Unless you can point to a passage in the literature that says "I made a mistake"

Sure, I’ve already done that several times.

Here’s what he said in the 1905 paper:

”light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body.”

And here is his correction in his 1916 book:

”In the second place our result shows that, according
to the general theory of relativity, the law of the con-
stancy of the velocity of light in vacuo, which consti-
tutes one of the two fundamental assumptions in the
special theory of relativity and to which we have
already frequently referred, cannot claim any unlimited
validity. A curvature of rays of light can only take
place when the velocity of propagation of light varies
with position.”

Here is an additional correction to that original 1905 statement, as published in his 1916 book, in the 1952 Appendix V:

”There is no such thing as an empty space, i.e. a space without field.”

I’ve underlined his original errors, his acknowledgment of the errors, and his corrections.

[milli360]

Sure, I’ve already done that several times.

I've not recognized them. For instance, the one you make below:

And here is his correction in his 1916 book:

”In the second place our result shows that, according
to the general theory of relativity, the law of the con-
stancy of the velocity of light in vacuo, which consti-
tutes one of the two fundamental assumptions in the
special theory of relativity and to which we have
already frequently referred, cannot claim any unlimited
validity.”

With that qualifier, "cannot claim any unlimited validity," it is no longer a correction, since the original 1905 paper did not say that it had unlimited validity, as you know.

I’ve underlined his original errors, his acknowledgment of the errors, and his corrections.

As near as I can tell, it is a misunderstanding.

Not that there might yet be some out there.