Question

What do you mean by a light year ? Is a light year unit of time or a unit of length ?

Answer 1

1. A light-year is a unit of distance. It is the distance a light photon travels in the vacuum in one Julian year. Denoted by ly.
2. The value of the one-light year is constant.
3. The value of one light-year can be numerically expressed in kilometers as 1 ly = 9.4607 × 10¹² km.
4. Similarly,1 light-year in miles = 5.88 × 10¹² miles, and 1 light-year in the Astronomical unit = 63241 au
5. A light-year is a unit of distance.
6. So, it's a unit of length not a unit of time.