hosszösszehúzódást

Hosszösszehúzódást, commonly translated as length contraction, is a phenomenon in special relativity where the length of an object moving relative to an observer is measured to be shorter along the direction of motion than its proper length. Proper length is defined as the length of the object when measured in its own rest frame, the frame where the object is stationary.

The effect is described by the Lorentz transformation equations. Specifically, the contracted length L is related to the proper length L₀ and the relative velocity v by the formula L = L₀√(1 - v²/c²), where c is the speed of light. As the velocity v approaches the speed of light, the term v²/c² approaches 1, and the square root term approaches zero. This means that the observed length L approaches zero.

Length contraction is only noticeable at speeds that are a significant fraction of the speed of light. At everyday speeds, the difference between the proper length and the observed length is infinitesimally small and therefore undetectable. The phenomenon is reciprocal; an observer in the moving object's frame would measure the stationary observer's frame to be length contracted. It is important to note that length contraction only affects the dimension parallel to the direction of motion. Dimensions perpendicular to the motion remain unchanged. While counterintuitive, length contraction, along with time dilation, is a fundamental consequence of the postulates of special relativity and has been experimentally verified.