# Steven Crothers , against BB

Discussion in 'Pseudoscience' started by river, Nov 30, 2017.

1. ### NotEinsteinValued Senior Member

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OK, then let's get back to more important things!

Do you have, or can you please link to, a mathematical derivation of this?

3. ### Q-reeusValued Senior Member

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It builds over the entire span of my relevant contributions this thread. Therefore I suggest reading through all my posts beginning at #79, and then see if that question still needs to be asked. Relevant links were given in #84 & #96 re standard predictions. Consider checking them out.
See examples of transmitted quantities given in #119 that do logically 'respect the metric' by violating flat spacetime expectations. A universal trend bucked according to GR only by static E & B fields.
Very unlikely experimentally detectable. Even in gravitational extremes with large static B fields like afaik still only theorized magnetars, observational evidence would have to be evaluated against many model dependent interacting factors.

5. ### Q-reeusValued Senior Member

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What further do you need? The problem was your thinking extra radial space created in SM somehow results in a leverage advantage of sorts. It doesn't. It's a matter of basic logic. What you quoted is sufficient. Let me throw this back at you. How could there not be a 1:1 radial displacement correspondence between two different elevations?

7. ### NotEinsteinValued Senior Member

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As I said: a mathematical derivation.

Basic logic is quite tricky to get right in the theory of general relativity, due to all kinds of non-intuitive things happening. I'd like to go step-by-step through a rigorous mathematical derivation, so that I don't have to depend on possibly faulty logic.

How about that link I posted in post #157? It explicitly states that measured lengths can be stretching due to gravity.

8. ### Q-reeusValued Senior Member

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It says there is more radial distance generated between spherical shells of given area than would exist in the absense of gravitating mass. So? The g_rr metric component operates on both the connecting rod and the space in which it is immersed - equally. There is no differential logically possible. What that means overall is - sure you have to feed out more tape measure to initially go from station A at r1 to station B at r2, wrt flat spacetime case. But once connected, any further proper feeding motions are recorded equally at A and B. This is surely obvious.

Last edited: Jan 6, 2018
9. ### NotEinsteinValued Senior Member

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In your (spherical) scenario radial distances and intervals pop up. So if there's some subtly involved when handling such cases, I'd like to make sure those subtleties are taking into account properly before I move on to other parts of the scenario.

So that raises the question I already asked in post #157: does this also affect the "dr" in your calculation?

As I already said: I don't trust any argument that simply says something is obvious, without any mathematical derivation to back it up, especially in the quantum and GR realms. However, in this case, yes, it's obvious.

10. ### James RJust this guy, you know?Staff Member

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31,847
Q-reeus:

Without delving into this further, I don't think I can make much sense of the content of this thread. It's been quite a while since I studied GR.

It's unfortunate that przyk bowed out of this discussion before it was resolved. He generally had a good handle on this stuff.

11. ### Q-reeusValued Senior Member

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OK no problem. Thanks for asking.

12. ### SchmelzerValued Senior Member

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Hm, there is no such animal as an "inertial frame" in GR. In GR we have only systems of coordinates, and no system of coordinates is preferred as being inertial. So, Q-reeus behaves correctly if he presupposes "non-inertial frames" without mentioning them - all "frames" (better: systems of coordinates) are non-inertial.

The "constant speed of light" in GR makes sense only if understood as an approximation, where one uses some system of coordinates which locally approximates an inertial SR frame, and adds the hypothesis that the guy who uses this system as "inertial" and, moreover, decides to use Einstein synchronization (which makes sense only if he assumes that it is he who is in rest, despite his inability to identify the rest frame by observation and the fact that he has probably a quite large speed relative to the CMBR frame, which is the most plausible candidate for the true rest frame) to measure the length, using the two-way time light needs.

13. ### Q-reeusValued Senior Member

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How would you describe use of Fermi coordinates then?: https://en.wikipedia.org/wiki/Fermi_coordinates
Not a global chart obviously but handy to adopt for local purposes.

14. ### NotEinsteinValued Senior Member

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You're right, I should have been more careful with my wording: I meant a freely falling reference frame. I apologize for the confusion, and not correcting it sooner.

15. ### SchmelzerValued Senior Member

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And even as a local chart, it is not really inertial. The nice properties mentioned in you link hold only on a particular geodetic. Which is a single trajectory, of measure zero, not even an environment of a point. It nonetheless remains useful for some local purposes, but it is of no fundamental importance for GR. You can do GR without using Fermi coordinates at all. At least I have never used them.