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

500,000 miles is a significant distance on Earth or within our solar system (it's about twice the distance to the Moon), but it's tiny compared to the vast distances between stars.

This is because a light-year is an enormous distance (about 5.88 trillion miles), so 500,000 miles represents a very small fraction of that distance.

No, this specific conversion is primarily used in astronomy and physics to understand and compare vast cosmic distances.