Unsatisfactory answer, though mathematically correct. The fuller explanation considers what constitutes "measurement" in a physics with a speed limit (lightspee

Unsatisfactory answer, though mathematically correct. The fuller explanation considers what constitutes "measurement" in a physics with a speed limit (lightspeed). We measure "intervals", i.e. lengths between to points of space or time. We'll see the intervals stetched/contracted by the Lorentz factor in another frame moving at a high constant velocity.