A micrometer (µm) is a unit of length in the metric system equal to one millionth of a meter. It's used for measuring very small objects like bacteria or the width of a human hair.

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, used to measure the vast distances between stars and galaxies.

This conversion is primarily for illustrating the immense difference in scale between microscopic measurements and astronomical distances. It's not a practical measurement for everyday science but is useful for educational analogies.

No, 100,000,000 micrometers is an extremely small distance when compared to a light-year. The conversion results in a value very close to zero, highlighting the vastness of cosmic distances.