[Verginius Rufus]

An astronomical unit is the distance from the earth to the sun. There are approximately as many astronomical units in one light year as there are inches in a mile.

So a model of the solar system that puts the earth one inch away from the sun would have the next-closest star, Proxima Centauri, about four and a quarter miles away. Other stars would be as many miles away as they are in fact light years away.

[SunkenCiv]

Thanks VR.