# Chapter: The mechanisms behind Non-Simultaneity

1. Oct 30, 2009

### Hans de Vries

Long overdue but here is the chapter:

http://physics-quest.org/Book_Chapter_Non_Simultaneity.pdf

4.1 Changing reference frames and non-simultaneity . . . . . . 2
4.2 Lorentz invariance of the wave equation. . . . . . . . . . . . 3
4.3 Observed simultaneity and Derived simultaneity. . . . . . . 5
4.4 Everybody sees the same light-cone frame . . . . . . . . . . 6
4.5 Passengers in rows and atoms in rows . . . . . . . . . . . . . 8
4.6 The velocity dependent viewing angle . . . . . . . . . . . . . 9
4.7 Simultaneity and the invariance of size . . . . . . . . . . . . 10
4.8 The relative versus the absolute viewing angle . . . . . . . 12
4.9 The ellipsoids of simultaneity . . . . . . . . . . . . . . . . . . . 16
4.10 From ellipsoids to spheres of simultaneity . . . . . . . . . . 20
4.11 Step 1: From absolute to relative positions . . . . . . . . . 24
4.12 Step 2: Viewing while Lorentz contracted. . . . . . . . . . 26
4.13 Simultaneity from the Spherical Mirror clock . . . . . . . . 28
4.14 Reversal of Lorentz contraction . . . . . . . . . . . . . . . . 32
4.15 Reversal of Time dilation. . . . . . . . . . . . . . . . . . . . . 34
4.16 Simultaneity from Huygens principle . . . . . . . . . . . . . 38
4.17 Simultaneity and the light wavefront direction . . . . . . 39
4.18 The wavefront rotation of matter waves . . . . . . . . . . 42
4.19 Negative energy waves and wavefront rotation. . . . . . 44

The subject is maybe a bit elementary for a QFT book but an
effort is made to visualize why exactly we experience different
simultaneities in different reference frames and why we experience
our world as invariant under boosts.

It is done so in a pedestrian step by step mode with lots of
visualizations. The most pedestrian path would start at 4.3 and
end at 4.12

Some feedback would be welcome.

Regards, Hans