Respuesta :
Answer: It is helpfull because it shows how long it takes to get to one place.
Explanation: Like for an example when you go on a vacation and you want to see how long it takes to get there. And that is what they use in space.
Answer: Astronomers can also establish how far back in time they are observing by measuring in light-years. Everything we see in the night sky has already happened since light takes time to reach our eyes.
Example: Interstellar and intergalactic distances are measured in light-years.
Example: Interstellar and intergalactic distances are measured in light-years.