Target880 t1_j20nnxd wrote
Reply to comment by [deleted] in ELI5: If astronomers use "light-years" for interstellar distances, why do we use AU for interplanetary distances instead of "light-minutes"? by concorde77
>Light minutes, on the other hand, are a unit of time, not distance.
Light minutes are a unit of distance just like a light year is. In SI base units are speed is in m/s and time is in seconds so speed * time =m /s * s =m
A light second is exactly 17,987,547,480 m
That is because the speed of light is by definition 299,792,458 m/s so just multiply that by 60 seconds and you ger the distance above. If we improve measurement it is the meter that changes not the speed of light. A meter is the distance light travels in 1/299,792,458 of a second in a vacuum.
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