To answer this question, you don't need to know the distance in one light year.
You only need to know that it represents a year of travel.
The light leaving Arcturus today will take 37 years to reach Earth.
If you are 11 now, then you will see that light (if you look at Arcturus)
when you are 48 years old.
It's enough to blow your mind. If Arcturus blew up yesterday,
you won't know it until you're 48 !
