≡ Menu

How Many Miles in a Light Year?


A Brief History of Time by Stephen Hawking

Another shift at work, another kid with a science question who wants me to answer it, rather than helping them find it. Earlier today the question was how many liters are in a gallon? Tonight it was How many miles in a light year?

The short answers:

According to the World Book Encyclopedia, there are 5.88 trillion miles in a light year, or 9.46 trillion kilometers.

According to Google’s conversion operator the number is 5.87849981 × 1012 miles.

Light travels at 186,82 miles per second, which is so fast that it’s impossible for me to actually think about what that means. If you’ve read this far, I’ll say that A Brief History of Time by Stephen Hawking has been my favorite, most accessible book about light, time, and space that I have read yet.

Comments on this entry are closed.