A micrometer (symbol: µm) is a unit of length in the metric system equal to one millionth of a meter.

A light-year is a unit of astronomical distance representing the distance that light travels in one year in a vacuum.

This is because a micrometer is incredibly tiny, while a light-year is extremely large, making the conversion result very close to zero.

While direct practical uses are rare due to the extreme scale difference, it's valuable for educational purposes to illustrate vast differences in measurement scales.