What is physical basis of Length Contraction in special relativity?

Einstein's theory of special relativity says that the length of an object such as a space ship moving at relativistic speeds undergoes a contraction along the dimension of motion. An observer at rest would observe the moving object to be shorter in length.How this works. What happens to physical properties of the object that it becomes shorter.


why it contracts only in context of stationary reference frame and is there any empirical evidence in support of this theory?|||The length contraction does not reflect any changes at all to the physical properties of the object. At one time (before the theory of relativity was accepted), there was a hypothesis that things contracted due to a physical interaction with the so-called "luminiferous ether" as they traveled through it; but this idea (along with the ether itself) was discarded in favor of relativity.





Relativity predicts that time intervals and distance intervals are relative, not absolute; and today we interpret length contraction as simply a manifestation of the relativity of distance measurements.





To put it more concretely: Consider how we'd measure the length of a passing space ship. We would record two events: say, "Event 1" is when the ship's nose passes a certain "stationary" signpost; and "Event 2" is when the ship's tail passes the same signpost. To calculate the ship's length, we then use this formula:





Length of ship = (time_of_event_2 鈭?time_of_event_1) / (speed of ship)





Now, consider a second observer, an astronaut floating in space who happens to be moving with the same velocity as the ship (so the ship appears stationary). This astronaut can measure the ship's length using the same technique, except he would substitute "speed of signpost" for "speed of ship". That doesn't matter, because the two speeds have the same measured value. However, time intervals are measured differently in the two reference frames; so the expression "(time_of_event_2 鈭?time_of_event_1)" has a different value when measured in the moving astronaut's frame as compared to the "stationary" frame. As a result, the length of the ship as measured in the moving astronaut's frame has a different value (always longer) than the length of the ship as measured in the "stationary" frame.|||the other guy deserves best answer.





conceptually, travelling at relativistic speeds distorts time, so you could argue that "distance" is altered, or "time" is altered. the physical "length" of an object is unchanged no matter how fast you are moving, your perception is altered|||http://en.wikipedia.org/wiki/Length_cont鈥?/a>