Question

Why are light-years more convenient than miles, kilometers, or astronomical units (AU) for measuring the distances to stars and galaxies?

Answer 1

Stars and galaxies are very far from the Earth. If their distance were denoted by km or AU then the numbers would be very large. Light-year makes the representation of distance to be concise.

Step-by-step explanation:

Stars and galaxies are very far from the Earth. If their distance were denoted by km or AU then the numbers would be very large. Light-year makes the representation of distance to be concise.

The distance light travels in one year is called a light-year.

`1\ lightyear = 3* 10^(8)* 365.25* 24* 60* 60 = 9.46728* 10^(15)\ m`

As it can be seen here that 1 light year = 9.46728×10¹⁵ m expressing distances of stars and galaxies which are more than 1 light-year becomes easier. Converting it to km will make it 9.46728×10¹² km does not make much difference.

1 Astronomical unit (almost the distance between the Earth and Sun) = 149597870700 m is also not enough to represent the distances of stars and galaxies.