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- “Reality” of length contraction in SR 13 answers
As an object moves faster, its time runs slower by factor X. I get why this is the case, but I'm not sure why distance is decreased by factor X as well.
1) Why does a moving object's travel distance decrease by factor X as its time decreases by factor X? The explanation I've heard is that because of v = d/t, since the moving object's speed is constant from different reference frames, its distance must decrease as time decreases. But I thought motion was relative?
2) Why does the object's physical length, from the reference frame of an observer, decrease by factor X? Even if the object travels a smaller distance from part 1), I'm completely lost on how that would affect its length.
Also, I'm aware of the unification between space and time in General Relativity, but I'm learning about Special Relativity and would prefer an explanation in that realm.