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From: Julio Di Egidio <julio@diegidio.name>
Newsgroups: sci.physics.relativity
Subject: [ANN] SR/InertialFrames v2.2.1
Date: Wed, 21 May 2025 13:47:48 +0200
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# SR/InertialFrames

SR/InertialFrames v2.2.1
STUDY.Physics.SpecialRelativity/InertialFrames
Physics case studies: Special Relativity: Inertial Frames
<https://github.com/jp-diegidio/STUDY.Physics.SpecialRelativity>

Contains:
   - Formal analysis
   - Interactive diagram
   - Source code

## The game

Bob and Alice pass by each other collinearly at a relative
constant speed.  They reset their respective clocks to zero
at the moment they are colocated.

## The outcome

The space-time diagrams make concrete the *clock hypothesis*,
i.e. proper time as **absolute time**, recovering absolute time
as the fundamental dynamic variable, and with it the relativistic
symmetry of the frame perspectives.

The diagrams also show that, relative to any frame of reference,
any particle moves into the future and in space at a speed that
is *faster than measured* in that frame (i.e. in a plane of
simultaneity) by exactly its Lorentz factor.  And this already
and essentially is **time travel**.

In particular, the 4-velocity of light in any frame of reference
is (scalarly) **infinite** in all components, its magnitude being
exactly the *measured light* *speed* times its Lorentz factor
(see [the formal analysis] for details).

## Changes

Changes from v1.0.0-alpha:
   - [Func] Added isochrones to diagram
   - [Func] Analysis fully rewritten
   - [Impl] Improved code throughout
   - [Tech] Restructured folders <= BREAKING: Most URL's have changed!