light years ly are an astronomy unit used for measuring length / distance generally used for values between 1 and 27000000000
light_time is distance. astronomy_unit is linear_unit. light_hour is not astronomy_unit. light_minute is astronomy_unit. light_hour is astronomy_unit. light_year is not astronomy_unit. light_minute is not astronomy_unit. light_year is measurement_of_distance_not_time. light_year is astronomy_unit. light_year is not measurement_of_distance_not_time.