Editing Length contraction (section)

{{short description|Contraction of length in the direction of propagation in Minkowski space}}
[[File:Relativistic wheels.gif|thumb|300px|right|Wheels which travel at 9/10 the speed of light.  The speed of the top of a wheel is 0.994 c while the speed of the bottom is always zero. This is why the top is contracted relative to the bottom. This animation is made with the assumption that the spokes of a wheel are much more elastic than its circumference. Otherwise there could be a rupture of the spokes or of the circumference. In the rest frame of the center of a wheel, wheels are circular and their spokes are straight and equidistant, but their circumference is contracted and exerts a pressure on the spokes.]]
{{Special relativity sidebar |consequences}}

'''Length contraction''' is the phenomenon that a moving object's length is measured to be shorter than its [[proper length]], which is the length as measured in the object's own [[rest frame]].<ref name=Dalarsson>{{cite book |title=Tensors, Relativity, and Cosmology |edition=2nd |first1=Mirjana |last1=Dalarsson |first2=Nils |last2=Dalarsson |publisher=Academic Press |year=2015 |isbn=978-0-12-803401-9 |pages=106–108 |url=https://books.google.com/books?id=KZOZBgAAQBAJ}} [https://books.google.com/books?id=KZOZBgAAQBAJ&pg=PA106 Extract of page 106]</ref> It is also known as '''Lorentz contraction''' or '''Lorentz–FitzGerald contraction''' (after [[Hendrik Lorentz]] and [[George Francis FitzGerald]]) and is usually only noticeable at a substantial fraction of the [[speed of light]]. Length contraction is only in the direction in which the body is travelling. For standard objects, this effect is negligible at everyday speeds, and can be ignored for all regular purposes, only becoming significant as the object approaches the speed of light relative to the observer.