What happens when light travels a year? You have a light-year.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
150 light years
1.19 light years
one light year
You can see a small rock two light years away from the moon.
With this rocket it would take at least take 10,000 years to travel one light year.
I wonder how many days it would take to travel one light year on a Segway.