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 yard is a unit of length in the imperial and US customary systems, equal to 3 feet or 36 inches.

A light-year represents an incredibly vast distance, covering trillions of miles, while a yard is a relatively small unit used for everyday terrestrial measurements.

No, yards are far too small to be practical for measuring astronomical distances. Light-years, parsecs, and astronomical units are used instead.