Because the definition of a lightyear is: how long light can travel in a year. Hope this helped;)
Chat with our AI personalities
a lightyear
100km is a distance, not a measurement of time. (kilometres)
Accurate measurements of time become possible after accurate measurement of length and mass because time taken by a heavy body to move a certain distance is more,and time taken by a light body to move a certain distance is less.
Measurement always deals with a distance of a line or a distance between to objects, distance between 2 points, and so on.
A minute is a measurement of time. A light minute is a measurement of distance. it's the distance light would travel in one minute. (That's about 10 million miles!)