# Lorentz-Fitzgerald contraction

There was a young fencer named Fisk,

whose movements were exceedingly brisk.

So fast was his action, the Lorentz Contraction

diminished his sword to a disk.

The Lorentz-Fitzgerald contraction is the contraction in length of a moving body, as measured by an observer at
rest with respect to the body, by the factor 1/√(1 - *ν*^{2}/*c*^{2}),
where *ν* is the relative speed of the moving body and *c* is the speed of light. Also called the **Lorentz contraction** or **Fitzgerald contraction** – the theory was proposed independently by both Hendrik Lorentz and George Fitzgerald – it one
of the surprising effects predicted by Einstein's special
theory of relativity. Compare with time
dilation.