light years

A light year is a measure of distance, representing how far light travels in one year. Since light moves extremely fast—about 186,000 miles (300,000 kilometers) per second—it can cover vast distances in a year. Specifically, in that time, light travels roughly 5.88 trillion miles (9.46 trillion kilometers). Astronomers use light years to describe the enormous distances between stars and galaxies, making it easier to communicate these vast scales without using unwieldy numbers. Essentially, a light year tells us how far away an object is based on the time it takes for its light to reach us.