Editing Length contraction (section)

== Symmetry ==
The principle of relativity (according to which the laws of nature are invariant across inertial reference frames) requires that length contraction is symmetrical: If a rod is at rest in an inertial frame <math>S</math>, it has its proper length in <math>S</math> and its length is contracted in <math>S'
</math>. However, if a rod rests in <math>S'
</math>, it has its proper length in <math>S'
</math> and its length is contracted in <math>S</math>. This can be vividly illustrated using symmetric [[Minkowski diagram]]s, because the Lorentz transformation geometrically corresponds to a rotation in four-dimensional [[spacetime]].<ref>{{cite book |author=Albert Shadowitz  |title=Special relativity |url=https://archive.org/details/specialrelativit0000shad  |url-access=registration  |isbn=0-486-65743-4 |publisher=Courier Dover Publications |edition=Reprint of 1968 |year=1988|pages=[https://archive.org/details/specialrelativit0000shad/page/20 20–22]}}</ref><ref name=sartori>{{cite book |author=Leo Sartori |title=Understanding Relativity: a simplified approach to Einstein's theories |isbn=0-520-20029-2 |publisher=University of California Press |year=1996|pages=151ff}}</ref>