## Invisibility of the Lorentz Contraction

Discussions on classical and modern physics, quantum mechanics, particle physics, thermodynamics, general and special relativity, etc.

### Re: Re:

DJ_Juggernaut » July 25th, 2018, 3:02 am wrote:
bangstrom » July 24th, 2018, 1:48 pm wrote:Where are the two mirrors and how does a moving object know its true angle from the light source?

The telescope is on one of the mirrors. If the mirrors are moving, the telescope needs to be tilted. All observers agree that Θ = 90 degrees and that the tilt angle gives the velocity v of the mirrors relative to the path of a photon, via tan(Θ - ϕ) = v/c.

If the mirrors are not moving relative to the path of a 90 degree photon, there is no need for the tilting of the telescope. All observers will agree with this too.

An object moving at relativistic speed appears rotated relative to an object at rest. A telescope would need to be tilted to receive the light and the mirror would need to be tilted at the same angle to receive or reflect light at a 90 degree angle so an observer at the telescope would not have a 90 degree “at rest” angle for comparison.
bangstrom
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### Re: Re:

bangstrom wrote:An object moving at relativistic speed appears rotated relative to an object at rest.

If it's true, and I doubt that it is, the rotation you speak of, has no validity on the true structure of the mirrors. It's only a visual effect. The physics of the photon or the telescope does not change.
Last edited by DJ_Juggernaut on July 26th, 2018, 11:35 am, edited 2 times in total.
DJ_Juggernaut
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### Re: What is up or down?

bangstrom » July 26th, 2018, 3:01 am wrote:The Stern-Gerlach experiment demonstrates that two electrons generated by the same event will have opposite spin states and that is nothing new.

The Stern-Gerlach experiment, as I see it, is a demonstration of the Lorentz force. The north pole pushes up a beam of electrons, the south pole pushes down a beam of electrons. Or vice-versa. Angular momentum or spin is irrelevant here. I fail to see how the Stern-Gerlach experiment demonstrates "spin" here.
DJ_Juggernaut
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### Re: What is up or down?

DJ_Juggernaut » July 26th, 2018, 9:49 am wrote:
If it's true, and I doubt that it is, the rotation you speak of, has no validity on the true structure of the mirrors. It's only a visual effect. The physics of the photon or the telescope does not change.

A mirror and a telescope are both subject to the same changes in the incidence of incoming light so the tilting of one is the same as the tilting of the other.
DJ_Juggernaut » July 26th, 2018, 10:33 am wrote:
The Stern-Gerlach experiment, as I see it, is a demonstration of the Lorentz force. The north pole pushes up a beam of electrons, the south pole pushes down a beam of electrons. Or vice-versa. Angular momentum or spin is irrelevant here. I fail to see how the Stern-Gerlach experiment demonstrates "spin" here.

The S-G apparatus has a north pole on one side and a south pole on the other so the magnets act together in the same direction. A single beam of electrons is split into two beams with one beam going up while the other is going down. The atoms are separated by spin direction which gives them a magnetic moment so they are either directed up or down in a magnetic field depending on their magnetic N-S orientation. This is the demonstration of “spin.”
bangstrom
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### Re: What is up or down?

bangstrom wrote:A mirror and a telescope are both subject to the same changes in the incidence of incoming light so the tilting of one is the same as the tilting of the other.

I disagree. This has nothing to do with aberration of light. The formula is clear on this.

bangstrom wrote:The S-G apparatus has a north pole on one side and a south pole on the other so the magnets act together in the same direction.

It's an in-homogeneous magnetic field. One of the poles is pointy. This makes the field lines spread out, somewhat radially (circularly) from the pointy pole. As I see it, charged particles passing through this type of field will therefore spread up and down, via Lorentz force.
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