how do you calculate light years
One light year is the distance that light travels in one year. The speed of light is 186,000 miles per second, or 300,000 km per second. There are 60 seconds in a minute, and 60 minutes in an hour. There are 24 hours in a day and a year is 365.25 days long. So, multiply 186,000 times 60 times 60 times 24 times 365.25.