2.03 Distances in Space

Valentina Iorizzo

What is a lightyear?

A light year is a large measurement for distance. Scientists use light years to talk about distances in space because it would be too complicated to use miles or kilometers.

Measuring Distances

1 light year = 5,879,000,000,000 miles, or 9,461,000,000,000 km. Instead of describing distances in miles, distances are described as a decimal of a light year, or more than one light year.

Specific Example

Planet Earth is 0.0000016 light years from the sun. Light travels at a speed of 186,000 miles per second. It takes 499.0 seconds, or about 8 minutes, for light to travel from the Earth to the sun.