A light-year is the distance that light travels in a vacuum in one Julian year. It's a unit used to measure astronomical distances.

One light-year is approximately 5.88 trillion miles.

Astronomers use light-years because the distances in space are so immense that using miles would result in incredibly large and cumbersome numbers.

25 light-years is equal to 146,969,821,243,935.4063 miles.