Discussion between 2 relativists and 1 anti-relativist

[ratiocinator]

Good Lord! Forget the silly Paradox of the Light Spheres. I'm sorry I even mentioned it, although I think I mentioned it because one of you two asked me what it was about STR that I didn't like. I know that my biases in favor of privileged/preferred reference frames, absolute simultaneity, and absolute motion lead me to believe that STR is nonsense. I know that relativists believe in relative simultaneity and all the things necessary and because they do, there are no paradoxes in relativity, except maybe the continued use of the term "Paradox' to refer to non-Paradoxes.

I actually thought you were going to say why you thought SR was wrong here, sorry if I misunderstood. From this it seems you just don't like it (because it's so counter-intuitive?) and have found a maverick who has a different theory that you like better.

I actually like mavericks in science and I've read some non-standard stuff from people like Penrose, Barbour (time doesn't really exist at all), and Smolin (absolute time). It just wouldn't occur to me to choose one, that I liked for some reason, and then declare the standard stuff to be rubbish.

I'll maybe look through some of the stuff you linked to but I'm actually studying the mathematics of General Relativity at the moment so I'm not going to spend a lot of time/brain power on this idea at the moment.

 

[Polymath257]

I'll maybe look through some of the stuff you linked to but I'm actually studying the mathematics of General Relativity at the moment so I'm not going to spend a lot of time/brain power on this idea at the moment.

If you have any questions, feel free to ask. What book/resource are you using?

 

[Terry Sampson]

I actually thought you were going to say why you thought SR was wrong here

SR's counterintuitivity doesn't qualify as a explanation for disbelief? What a revelation! I'm devastated. Where's my white flag? LOL!
Have you ever met a confirmed anti-relativist who didn't object to SR on grounds of counterintuitivity? I haven't.
I wish I could offer stories of a childhood filled with abusive relativists to get your sympathy, but I can't..

I actually like mavericks in science

Good on ya. Some of my best friends are atheists. Except for the militant atheists (who are not among my friends), the clever ones are a hoot 'n a half.

I'll maybe look through some of the stuff you linked to

If you do, I'll never respect you again. Relativists have no good reason to read heretics' works on well-established mainstream science.
Hmmm, ... I take that back: I suppose brief entertainment and research purposes, if you're planning to go into teaching physics, are good reasons. Future teachers of relativity ought to have some training in understanding heresies, IMO.

Take care

P.S. Trivia: If I remember correctly,... Ah! ... here it is:

Was the wiki article (which doesn't even mention Levy) right when it said

I'm not sure why you thought a wiki article about LET should mention Joseph Levy, perhaps you think it would at least give him notoriety if not credibility, but for what it's worth (which isn't much if not nothing):
Joseph Levy - Natural Philosophy Wiki

 

[Polymath257]

SR's counterintuitivity doesn't qualify as a explanation for disbelief? What a revelation! I'm devastated. Where's my white flag? LOL!

No, of course it doesn't. There is no obligation that the universe be consistent with your intuitions.

Have you ever met a confirmed anti-relativist who didn't object to SR on grounds of counterintuitivity? I haven't.
I wish I could offer stories of a childhood filled with abusive relativists to get your sympathy, but I can't..

OK, so anti-relativists commonly make the mistake of thinking the universe must abide by their intuitions. Too bad.

 

[ratiocinator]

SR's counterintuitivity doesn't qualify as a explanation for disbelief? What a revelation! I'm devastated. Where's my white flag? LOL!
Have you ever met a confirmed anti-relativist who didn't object to SR on grounds of counterintuitivity? I haven't.

Just seems a rather odd reason to me. As I said before, it's a long way from the most counter-intuitive notion if physics. Are you anti-QM too?

 

[Terry Sampson]

Are you anti-QM too?

I suspect that I would be if I understood it, but can't say definitively because I don't.

 

[Polymath257]

For me, something being counter-intuitive is a good opportunity to adjust my intuitions. That is what learning is all about, in my view.

There are a great many proven results in math that are, initially, counter-intuitive. They are still true. All that means is that my intuition is wrong and needs to be adjusted.

 

[ratiocinator]

If you have any questions, feel free to ask. What book/resource are you using?

That's most kind of you, thanks! I'm using D'Inverno Introducing Einstein's Relativity - just getting to the end of the Formalism of Tensors section and getting bogged down in some of the proofs of various symmetries that are given as exercises. I seem to be getting there in the end (with some help from the web and some other books) but I may well take you up on the offer if I get really stuck.

 

[Polymath257]

That's most kind of you, thanks! I'm using D'Inverno Introducing Einstein's Relativity - just getting to the end of the Formalism of Tensors section and getting bogged down in some of the proofs of various symmetries that are given as exercises. I seem to be getting there in the end (with some help from the web and some other books) but I may well take you up on the offer if I get really stuck.

Yes, tensors are a leap. Wait until you get to Christoffel symbols. They are necessary to define the various tensors associated with curvature. One of my physics professors called them 'Christ awful symbols'.

 

[ratiocinator]

Yes, tensors are a leap. Wait until you get to Christoffel symbols. They are necessary to define the various tensors associated with curvature. One of my physics professors called them 'Christ awful symbols'.

Yes, I've come across them already, it's some of the symmetries of the Riemann tensor that I've been proving, using (as suggested the hint) geodesic coordinates, so the connection goes to zero at some point.

 

[Valjean]

I'd also say you should be very clear about what, exactly, is claimed in the length contraction.

Suppose a pole is at rest and has a length 10 feet in my reference frame. Someone goes past me at 60% of the speed of light and in a direction aligned with the pole. They measure the length of the same pole at an instant in their frame and determine it to be 8 feet long.

Is that good for a start?

I'm using that sqrt( 1- (.6)^2 ) =.8

"There was a young fellow named Fisk
Who's fencing was exceedingly brisk
So fast was his action, that FitzGerald contraction
Reduced his rapier to a disk."

 

[Polymath257]

Yes, I've come across them already, it's some of the symmetries of the Riemann tensor that I've been proving, using (as suggested the hint) geodesic coordinates, so the connection goes to zero at some point.

Yes, those can be fun to show.

I come from a different direction. Starting with differential geometry, you can discuss tangent and cotangent vectors (vectors with upper or lower indices). Then, a connection allows you to do a covariant derivative. The Christoffel symbols, the Riemann tensor and associated constructs are actually best done at this level and have to do with the covariant derivative and to what extent order of application is relevant. Parallel transport and geodesics can be defined at this point also.

Finally, if there is a metric, we can raise and lower indices and select a particular connection that preserves lengths through parallel transport.

When taken from this POV, things are much more abstract, but most of the symmetries are easier to establish.

 

[ratiocinator]

Yes, those can be fun to show.

I come from a different direction. Starting with differential geometry, you can discuss tangent and cotangent vectors (vectors with upper or lower indices). Then, a connection allows you to do a covariant derivative. The Christoffel symbols, the Riemann tensor and associated constructs are actually best done at this level and have to do with the covariant derivative and to what extent order of application is relevant. Parallel transport and geodesics can be defined at this point also.

Finally, if there is a metric, we can raise and lower indices and select a particular connection that preserves lengths through parallel transport.

When taken from this POV, things are much more abstract, but most of the symmetries are easier to establish.

Doesn't sound too different from this approach. After the first section (basically an overview of SR, which I've studied before), it went more abstract and introduced manifolds, coordinate transformations, covariant and contravariant tensors, then into tensor calculus, Lie and covariant derivatives, affine connection, metric, flatness, and defining the various curvature tensors. Not going to get to do any actual GR until after "integration, variation, and symmetry" and revisiting SR.

I looked at a few books and this looked reasonably accessible. I've done most of my recent studying with the Open University (UK) or by buying their materials (after they became much more expensive), which are great for self-study, but they don't do a proper mathematical GR course.

 

[ratiocinator]

I suspect that I would be if I understood it, but can't say definitively because I don't.

I suspect you would because it's even more counter-intuitive, but it's also even more difficult to deny than SR because it's actually used in so much modern engineering. I first learned about it on a semiconductor design course.

Why do you think the universe should behave according to human intuition (outside of the sort of environment we evolved in)?

 

[Terry Sampson]

Why do you think the universe should behave according to human intuition (outside of the sort of environment we evolved in)?

I don't object to the question and I recognize that you are addressing me because, at the moment, I seem to you to be a prime example of someone who thinks that the universe should behave as I have intuited it should. But I think the question merits wider input from RF's larger community, or perhaps the RF community (which includes me) ought to be allowed to weigh in on the matter. "Merit" and "ought" aside, I'd think it would be entertaining and maybe even enlightening, briefly or not, to see what RF's menagerie has to say about intuitions, beliefs, and why the universe should behave as anyone intuits and/or believes as anyone says it should. For that reason, I suggest that we take the question out of this thread and put it before the masses, unless that's been done already and I just don't know it. Are you amenable to that?

 

[ratiocinator]

I don't object to the question and I recognize that you are addressing me because, at the moment, I seem to you to be a prime example of someone who thinks that the universe should behave as I have intuited it should.

I just find it curious when people do think the universe should conform to intuition, at least outside the scope of our immediate environment - and even that is often wrong in some respects, like probability.

But I think the question merits wider input from RF's larger community, or perhaps the RF community (which includes me) ought to be allowed to weigh in on the matter. "Merit" and "ought" aside, I'd think it would be entertaining and maybe even enlightening, briefly or not, to see what RF's menagerie has to say about intuitions, beliefs, and why the universe should behave as anyone intuits and/or believes as anyone says it should. For that reason, I suggest that we take the question out of this thread and put it before the masses, unless that's been done already and I just don't know it. Are you amenable to that?

I'm not aware of it being done before and I'm happy to make it a wider discussion. I have other things to do for the rest of the day but if you want to post in a more general area, I'll pick it up tomorrow sometime.

 

[Polymath257]

I don't object to the question and I recognize that you are addressing me because, at the moment, I seem to you to be a prime example of someone who thinks that the universe should behave as I have intuited it should. But I think the question merits wider input from RF's larger community, or perhaps the RF community (which includes me) ought to be allowed to weigh in on the matter. "Merit" and "ought" aside, I'd think it would be entertaining and maybe even enlightening, briefly or not, to see what RF's menagerie has to say about intuitions, beliefs, and why the universe should behave as anyone intuits and/or believes as anyone says it should. For that reason, I suggest that we take the question out of this thread and put it before the masses, unless that's been done already and I just don't know it. Are you amenable to that?

I'm game for that.