How to Calculate a Light Year ?

A light-year is measured by the distance ( NOT time! ) light will travel in one year. This can be calculated by multiplying seconds in a year × the speed of light.

Steps -

Calculate Seconds in a year

 

1. The formula for working out seconds in a year.
   • Seconds in a minute × minutes in a hour × hours in a day × days in a year.
2. Multiply 60 seconds by 60 minutes.
   • 60 × 60 = 3,600 seconds.
3. Multiply 3,600 seconds by 24 hours.
   • 3,600 × 24 = 86,400 seconds.
4. Multiply 86,400 seconds by 365 days.
   • 86,400 × 365 = 31,536,000 seconds in a year.

Speed of Light

 

1. • 186,000 miles per second.
   • Roughly 300,000 kilometres per second.

Multiply by Speed of Light

 

1. • 31,536,000 × 186,000 = 5,865,696,000,000 miles per year. ( 5.865696 × 10¹² )
   • 31,536,000 × 300,000 = 9,460,800,000,000 kilometres per year. ( 9.4608 × 10¹² )

One light-year in words

 

1. Five Trillion, Eight Hundred Sixty-Five Billion, Six Hundred Ninety-Six Million miles.
2. Nine Trillion, Four Hundred Sixty Billion, Eight Hundred Million kilometres.