A light-year is the distance that light travels in a vacuum in one Julian year (365.25 days). It's a unit of astronomical distance.

A nanometer (nm) is a unit of length in the metric system equal to one billionth of a meter. It's often used to measure atomic and molecular scales.

This conversion is primarily used in advanced astrophysics and cosmology where researchers need to reconcile vast interstellar distances with the incredibly small scales relevant to certain physical phenomena or measurement instruments.

One light-year is equal to approximately 9.461 x 10^24 nanometers.