**Length Contraction** - Length contraction is analogous to time dilation, in the sense that it is a phenomenon that is observed of objects in moving frames of reference. As in the previous section, consider an observer who is stationary in a particular frame of reference, which we will call frame A (e.g. someone standing still on a flat road - the road being the frame of reference). Suppose that this person has a rod that has length L. Now consider a second observer in a frame of reference (frame B) that is moving with respect to our original observer (e.g. in a car), and suppose that this observer also has a rod of length L, as measured in frame B. (Definition provided by Marts100)