1 ly is a distance, defined as the distance travelled by light in a year. hence 2.5 mn lys away means it takes 2.5mn years for light to reach earth b/c light travels a distance of 1 light year in a year
ly is a distance, defined as the distance travelled by light in a year. hence 2.5 mn lys away means it takes 2.5mn years for light to reach earth b/c light travels a distance of 1 light year in a year
