Do people actually understand the theory of relativity? - by Kirsten Hacker - Quora Question review

This document contains a review of the answer by by Kirsten Hacker on the question in Quora: "Do people actually understand the theory of relativity?"
To order to read all the answers select: https://www.quora.com/Do-people-actually-understand-the-theory-of-relativity

Contents

Reflection

1. Answer Review

Generally, no. After watching some relativity youtube videos, remembering the stories my teachers told me, and reading many of the answers on Quora, my conclusion is : no. People here and on youtube do not understand relativity at all. Even those who teach the stories of the paradoxes to students largely don't know what they are talking about.

If you work with accelerators, you need relativity to explain how things work.

Requires a detailed explanation
If you work in astronomy, you use relativity to interpret things, but you don't really have a controlled experiment where you can manipulate variables easily.
That is correct
Based on what I know about how relativity works with particle beams, all of the youtube videos involving trains, tunnels, flashlights and whatnot look WRONG in some significant way.
Requires a detailed explanation
Moving trains do not "look" contracted to a stationary observer. Depending on the method used to "see" them, either their particles look contracted and the train is a normal length OR their particles look normal but the train looks streaked out and long.

When a bunch of particles is accelerated, the fields of the particles contract like pancakes in the direction of travel, but the space between the particles doesn't contract. Since most of an object is made up of space, it won't look contracted after it has been accelerated.

How do you know that?
I spent most of my phd/postdoc career measuring the length of relativistic particle bunches in various ways and they are the same length in the lab frame before and after they are accelerated, but after they are accelerated, their particles are short in the lab frame.
In the rest frame of the particle bunch relative to our rest frame, the particle bunch is longer compared to when it was moving more slowly. For more details, see: Is length contraction only a result related to observation, or a real contraction?

This interpretation is consistent with Feynmann's How did Feynman explain that magnetic fields are created by moving charges due to length contraction? and Kyle Foot's answer to Why does a moving charge produce a magnetic field around it? but not necessarily with all of Einstein's writings involving short measuring sticks and contracted distances between objects.

I tried to give answers to other questions on relativity, but because I didn't answer in terms of nonsensical imaginary trains, people thought I was wrong and downvoted my answers.

C'mon Quora - you are believing in fairytales.

Reflection 1 - Question Review

Accordingly to Kirsten Hacker the Answer on the Question: "Do people actually understand the theory of relativity?" is No and explains Length Contraction. The problem is that is only a small part of The general theory of Relativity, and does not cover all the concepts involved.

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Created: 1 April 2024

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