Why in the world would Einstein suggest....

@dalehileman,

Quote:

Hell Ora that's an easy one They'd be the same youngsters they were when they launched

Not really, Dale. It only seems easy because you have been induced to accept the people in the bleachers as a preferred frame where they are really at rest and where both A and B are really moving at equal speeds.

Of course SR would say from the outset that you could never know this. But, that aside, let's look at what SR would tell about how A "sees" things.

The instant A stops accelerating, he will immediately declare that he is no longer moving. Why? Because SR REQUIRES him to say that.

Now what?

A will see both B and the bleacher approaching him. He will see B as coming at him twice as fast as the bleachers, and therefore predicts they will reach him at the exact same time (which they do).

Then he sees them both go past him, but of course B is still moving twice as fast as the bleachers. Eventually both fade out of sight. First B does, then the bleachers, in twice the time it took B to be beyond his horizon.

All this time he has not moved one inch. Assuming that they don't later change speeds, it would be impossible for the bleachers and B to ever "come back" to him, and reach him, at the same time again.

Of course B will see it the same way as A, in reverse Why? Because SR also REQUIRES him to claim he is not moving as soon as he quits accelerating.

But under either scenario, A, B, and the bleachers could never all be back at the same place at the same time again, unless they did NOT maintain a uniform speed.

If we accept the example as accurately describing what "really" happens, then it is obvious that BOTH A and B are just plumb WRONG when they believe what SR insists that they believe.

3 Replies

@layman,

To carry it one step further, what would SR tell us about how C (the bleachers) "sees" things?

As with A and B, SR MANDATES that C claim that he is motionless. Given that, how would he see things? He would see them just the way they were described in the hypothetical. And, implicit in the whole hypothetical is the assumption that they are RIGHT.

Since they are right, and the other two stooges are completely wrong, they have the preferred frame going for them.

1 Reply

@layman,

Quote:

But under either scenario, A, B, and the bleachers could never all be back at the same place at the same time again, unless they did NOT maintain a uniform speed

I get what you're saying but I'm not convinced that after his takeoff SR insists he must consider himself still. As I understood it the SR participant can only cite relative speeds

My supposition was indeed based on the notion of a "preferred ref" just as we're supposing the SR does, if only subliminally. In fact, I'm just a third party here, just stumbling around in the maze of apparent contradictions

So Ora what's your response so far

4 Replies

@layman,

Quote:

To carry it one step further, what would SR tell us about how C (the bleachers) "sees" things?

I'd suppose when they fire off C sees A's and B's clocks stop. Then if he could live long enough he's see 'em coming back from the opposite directions, still in their youth

Quote:

As with A and B, [they have the preferred frame going for them] SR MANDATES that C claim that he is motionless.

As I mention above I've never heard it expressed that way but yes, that's the tacit assumption, isn't it

As I said above, I'm willing to consider anything. Ora where are you

.

1 Reply

@dalehileman,

Quote:

I get what you're saying but I'm not convinced that after his takeoff SR insists he must consider himself still.

Well, only in a figurative way, of course. In real life, each and every person is quite free to get on a train and concede that he is moving. In fact, in real life, every sane person would make that concession.

A more literal way of stating it might be something like this: The calculator, under the protocols of SR, must now treat (for mathematical purposes) each as at rest, when he is calculating what "their perspective" would be.

If he does not, the whole theory falls apart.

That's what this physics professor is saying:

Quote:

ALT differs from SR in several respects. ALT maintains absolute simultaneity for all observers, while SR implies local differential simultaneity [2, 3]. ...With directional time dilation, observers in a PRF will observe that clocks moving relative to the PRF run slower, while observers in non-PRF reference frames will observe that clocks in the PRF run faster (i.e., exhibit time contraction)...

http://able2know.org/topic/265997-21#post-5886745

For SR to work out mathematically, and be in accord with it's postulates (including the assertion that "simultaneity is relative") the two observers MUST DISAGREE with each other about who is moving. If they didn't you would have an AST (absolute simultaneity theory).

1 Reply

@layman,

I probably excised too much from that last quote. The paper also says:

1.'The corollary to this is that SR maintains light speed isotropy between inertial reference frames, while ALT implies anisotropies in the one-way speed of light, although the two-way speed of light for ALT is c ."

Restated in more everyday terms: In SR the speed of light is constant, in an AST the speed of light is NOT constant (even though it will be measured as such).

2. "The two theories also differ in that time dilation between inertial reference frames is reciprocal for SR and directional for ALT."

Here "directional" simply means "non-reciprocal."

As I have said in other posts, one simple difference is that in an AST the two observers will agree on who is moving. This was the point of the OP. In an AST, the guy on the train will acknowledge that the train is moving (relative to the earth). In SR, the guy on the train will deny that he is moving.

As his paper makes clear, the ALT he is talking about is a mathematical formula, but it is not the theory itself. He calls a theory which uses the ALT formula an AST (absolute simultaneity theory).

When the guy on the train concedes that he is moving, he, by virtue of that concession, knows that his clock is running slower that the earth clock. In SR he insists that it is the earth clock that is running slower (because, in SR, it is treated as the "moving clock" for him). Of course he will be wrong when he makes this insistence, but...

Because SR compels different observers to make contradictory claims, the "paradoxes" arise.

1 Reply

@layman,

Carrying that over to the twin paradox, if the travelling twin had simply acknowledged that, after having been accelerated to near light speeds, he, not the earth, was the one who was (relatively) moving, then there would be no difference to try to somehow reconcile. Both twins would simply have agreed, at each and every step of the way, that the travelling twin was in fact aging more slowly.

When SR concedes that each clock has not, literally, been running slower than the other, it is simply reverting to an AST where the earth frame is the preferred frame.

It all depends on your assumptions, Dale. If I incorrectly assume that all cats are black, I will conclude that your pet is black if it is a cat.

Conversely, If I (again incorrectly) assume that all cats are white, I will conclude that your pet is white if it is a cat.

Your cat could in fact be black, white, or any other color. That wouldn't have any bearing whatsoever on what I would conclude about your cat, given my assumption.

0 Replies

@dalehileman,

Quote:

As I understood it the SR participant can only cite relative speeds

Yeah, that's right. But what does it mean? What is it saying?

It means that A can't just say: "B is travelling at half the speed of light."

Instead A must say: "B is travelling at half the speed of light, relative to me."

But, then again, if A assumes he is "motionless," then the two are the same thing (to him, at least).

According to SR every clock in the universe which is moving is a clock that runs slower than his (A's, that is). That's because all "motion" is defined relative to him. If it's moving, it "moving relative to him."

So, in essence, every time the SR adherent chooses a frame of reference to calculate from, that frame is treated as an "absolute frame of reference."

0 Replies

@dalehileman,

dalehileman wrote:

Hell Ora that's an easy one They'd be the same youngsters they were when they launched.

First things first. Does my proposed hypothetical address the question that you have been trying to figure out over these past years?

dalehileman wrote:

But I'm wondering why it would matter that they swished on past Earth (if it's still in existence)

I did not include Earth anywhere within my proposed hypothetical.

0 Replies

@layman,

layman wrote:

Assuming that they don't later change speeds, it would be impossible for the bleachers and B to ever "come back" to him, and reach him, at the same time again.

This hypothetical is taking place in a finite universe that loops on itself, so that if you go far enough in the same direction you will eventually end up in the place where you started.

1 Reply

@oralloy,

Quote:

This hypothetical is taking place in a finite universe that loops on itself, so that if you go far enough in the same direction you will eventually end up in the place where you started

Sure, I understood that. That's not the issue.

The quote you posted says "at the same time." I mean, it could, I suppose, happen after multiple revolutions, but not after one.

Why? Because they are not moving away at the same speed. That's why I said "unless they did NOT maintain a uniform speed."

0 Replies

@dalehileman,

I said:

Quote:

Instead A must say: "B is travelling at half the speed of light, relative to me."

Now, this statement is undoubtedly truly reciprocal.

If B is travelling at half the speed of light with respect to A, then A must ALSO be travelling at half the speed of light with respect to B.

One problem. SR doesn't allow A to be the one who is travelling (moving) from his viewpoint.

http://able2know.org/topic/265997-18#post-5885131

0 Replies

@dalehileman,

Quote:

I get what you're saying but I'm not convinced that after his takeoff SR insists he must consider himself still.

Dale, this quote is from a Harvard Physics Professor who wrote an explicatory treatise on SR (citation below). You should trust him more than me on anyone else on this site:

Quote:

One might view the statement, "A sees B's clock running slow, and also B sees A's clock running slow," as somewhat unsettling. But in fact, it would be a complete disaster for the theory if A and B viewed each other in different ways. A critical fact in the theory of relativity is that A sees B in exactly the same way that B sees A.

http://www.people.fas.harvard.edu/~djmorin/chap11.pdf (Page XI-14)

Within the context of SR you can replace "see's B's clock running slow" with the phrase "sees B as moving." That it because it is always the moving clock which "runs slow."

So, he says: " it would be a complete disaster for the theory if A and B viewed each other in different ways. A critical fact in the theory of relativity is that A sees B in exactly the same way that B sees A."

I don't like his use of the term "fact," here, because he's just talking about a theory. It is a critical premise (axiom--or postulate, or mandatory mathematical procedure) that he is really talking about, not a "fact."

But terminology aside, he's saying the theory will fall apart if A and B do not assume contradictory things, i.e., A must say B is moving while B must say A is moving.

Of course they can "see" it that way, all year long, and it will still be just as logically impossible as ever. How you "see" something is not necessarily what it is.

Another interesting comment from this same professor in the same paper:

Quote:

We'll start with the speed-of-light postulate:

"The speed of light has the same value in any inertial frame."

I don't claim that this statement is obvious, or even believable. But I do claim that it's easy to understand what the statement says (even if you think it's too silly to be true).

Page XI 7

He's not going to claim it's believable because, well, it's not.

At least he's not trying to play you for a chump, as many of these Profs do. Of course, that's the game many professors always play. They try to give the impression that some things are so subtle, so insightful, and so brilliant that only extremely smart people, like, ahem, THEM, for example, have the capacity to realize "the truth" even when it's 'incredible."

It is of course true, as many experiments have shown, that all inertial frames will measure the speed of light to be the same. But that is quite a different thing than saying the speed of light IS the same.

1 Reply

@dalehileman,

Dale, we started, but never finished pursuing, these questions:

Quote:

Dale: Of course they can "see" it that way, all year long, and it will still be just as logically impossible as ever. How you "see" something is not necessarily what it is.

Quote:

Layman: Well, Dale, when you really think about, how could there NOT be.

Leaving aside the question of an "absolutely motionless point" for now, let's just examine the need for a preferred frame.

Look at the example Oralroy brought up where 3 potential "viewpoints" (frames) are involved.

Now suppose you seriously and consistently maintained that there was no possible way select one as a "preferred frame." By "select" I don't mean arbitrarily designate one as preferred for the purposes of calculation. I mean that you could "never" know which, if any, of the 3 perspective was "actual" or "true."

Well, then, OK. But don't tell me you have any "theory of motion" which makes "accurate predictions" about the real world. You are simply telling me that you have no clue about, and are incapable of predicting anything at all (accurately or not) about, physical "reality."

Such a "theory" is NOT a scientific physical theory. It is merely a metaphysical statement.

To reach ANY conclusion about anything, you must have a starting point. If there is "no where to start" when trying to decide if any of A, B, or C are even close to being accurate in their assumptions, you are going to get absolutely no conclusions.

That is why the GPS does NOT use SR. It uses an AST (absolute simultaneity theory) to makes it predictions (which turn out to be amazingly accurate, for practical purposes). If it tried to rigorously employ a strict SR theory, that would simply lead to a never ending lack of closure, where every clock was deemed to be slower than every other clock, depending on which clock you were assessing at any given time.

1 Reply

Oh dear, still selectively preaching the words of "authority"! You forgot to mention he said this....

Quote:

You shouldn’t feel too bad about having spent so much time learning about a theory that’s just the limiting case of another theory, because you’re now going to do it again. Relativity is also the limiting case
of another theory (quantum field theory). And likewise, quantum field theory is the limiting case of yet another theory (string theory). And likewise. . . well, you get the idea. Who knows, maybe it really is turtles all the way down.

David Morin.(Limerick Writer, Physics Dept, Harvard)

3 Replies

@layman,

Too late to edit!!

In that last post I had intended to post this quote of yours, Dale:

Quote:

I agree most wholeheartedly that the SR bunch is sloughing off that "preferred ref" and I have no idea how they justify doing so. But if there is one as you maintain , I simply can't see how or why

The post might make a little more sense that way.

0 Replies

@fresco,

Do you have a point, Fresco?

0 Replies

@fresco,

Quote:

Who knows, maybe it really is turtles all the way down.
David Morin.(Limerick Writer, Physics Dept, Harvard)

For anyone who may not recognize the "turtles" reference.

I've forgotten, exactly, but I think maybe it was Bertrand Russell who told the tale of being confronted by an elderly lady after giving a public lecture. Apparently the lecture contained some references, perhaps in connection with SR, about the earth's motion through space.

Basically, the woman said: "You're full of ****, Bertrand. The earth does not "float in space." It rests on the back of a giant turtle."

So, playing along, Russell asked: But what does the giant turtle rest on?

She said: Another giant turtle, that's what!

So, Russell asked: And what, pray-tell, does THAT turtle rest on?

She said: "I see where you're trying to go, young man, so don't get wise with me. I'll cut this short. It's turtles, all the way down."

0 Replies

@fresco,

Quote:

And likewise, quantum field theory is the limiting case of yet another theory (string theory).

Isn't string theory still widely considered to be a huge "scientific" embarrassment and a huge waste of the resources devoted to it?

From all appearances, it's really not physics at all. It's math. It's unclear to me just when mathematicians superseded physicists in the realm of theorizing about physical phenomena, but I suspect it all started with that fraud, Minkowski.

0 Replies

@layman,

Another observation concerning this statement, made by Dr. Morin, of Harvard:

Quote:

We'll start with the speed-of-light postulate:

"The speed of light has the same value in any inertial frame."

I don't claim that this statement is obvious, or even believable. But I do claim that it's easy to understand what the statement says (even if you think it's too silly to be true).

I happen to agree with him on all counts. It's easy to understand what the statement says.

But it is not easy to accept the validity of claim.

Those are two completely different issues. Yet most people seem to think they are one and the same. They NEVER seriously analyze the assumptions of SR itself. They simply accept them as somehow being "indisputable fact."

So they assume (and assert) that anyone who questions the assumptions of SR "just doesn't understand" SR. They have accepted its premises unconditionally. Once you accept the assumptions, then the rest follows, logically.

But, it you don't accept those assumptions, then all issues of "fact" are not immediately answered by resorting to the "explanation" provided by SR. It seems to me that the most difficult thing for people to do (myself included) is examine the premises which they currently accept as "indisputable."

1 Reply

Why in the world would Einstein suggest....

Related Topics

Quick Links

My Account

able2know