Students are taught that one of the consequences of Einstein’s special theory of relativity is that moving objects contract in length in the direction parallel to their velocity vector. But does this contraction actually happen or is it some sort of illusion? The answer is yes, length contraction actually happens and no, it is not an illusion.

Einstein in 1904 stated (as quoted in the book One, Two, Three … Infinity by George Gamow, 1961 page 97) “we deal here with the contraction of space itself, and all material bodies moving with the same speed contract in the same way simply because they are imbedded in the same contracted space”.

A common misconception is that the high speed of the object causes its length to contract as if caused by some process in the object. Length contraction occurs due to the high relative speed of the reference frames in which the observation is made.