A light-year is the distance 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 equal to one billionth of a meter (10^-9 m). It's commonly used in science and technology, especially in fields like optics and nanotechnology.

While rarely done in practical astronomy, this conversion emphasizes the astronomical difference in scale between vast cosmic distances and the incredibly small dimensions of atoms and molecules.

One light-year is equal to approximately 9.461 x 10^21 nanometers.