Question

According to astronomers, what is a "light year" answer key

Answer 1

A light-year is defined as the distance the light can cover in one year.

The light travels at speed of
`c=3 \cdot 10^8 m/s`, and one year converted into seconds is

`1 y = 365 (d)/(y) \cdot 24 (h)/(d) \cdot 60 (m)/(h) \cdot 60 (s)/(m)=3.15 \cdot 10^7 s`

So the distance covered by the light in one year is

`S=vt =(3 \cdot 10^8 m/s)(3.15 \cdot 10^7 s)=9.45 \cdot 10^(15) m`
And this is the distance that corresponds to one light-year.