Question

define light year in about fifty words

Answer 1

here is your ANSWER-
: a unit of length in astronomy equal to the distance that light travels in one year in a vacuum or about 5.88 trillion miles (9.46 trillion kilometers)

Answer 2

FOR THOUSANDS OF YEARS PEOPLE HAVE BEEN CURIOUS ABOUT LIGHT , ITS PROPERTIES AND BEHAVIOR. ONE OF THE MOST IMPORTANT SENSES THAT WE HUMAN BEINGS HAVE IS TO SEE THE WORLD AROUND US . THIS IS MOST IMPORTANT FOR OUR SURVIVAL . LIGHT ENABLES US TO SEE. GENERALLY LIGHT TRAVELS IN A STRAIGHT LINE IN A UNIFORM TRANSPARENT MEDIUM . THIS MODE OF PROPAGATION OF LIGHT IS CALLED RECTILINEAR PROPAGATION OF LIGHT.