How do scientists use light years?to report report distances distances between between objects objects in in space space and and study study the the early early universeuniverseto to measure measure how how fast fast an an object object is is traveling traveling and and determine determine the the origins origins of of the the universeuniverseto to measure measure the the amount amount of of light light that that a a star star produces produces and and determine determine how how hot hot it it is is burningburningto to determine determine the the age age of of an an object object in in space space and and study study how how it it was was formedformed