A nanometer (nm) is a unit of length in the metric system equal to one billionth of a meter. It's used for measuring extremely small things like atoms and molecules.

A light-year is the distance that light travels in one year in a vacuum. It's a unit used to measure vast distances in space.

Because a nanometer measures incredibly tiny distances at the microscopic level, while a light-year measures enormous distances across the universe. The difference in scale is immense.

Directly converting 10 million nanometers to light-years isn't a common daily task. However, it's useful for understanding and teaching the vast differences in scale between the microscopic and the cosmic.