Light Years
June 28th, 2011
06:14 PM ET

Glossary: lightyear

A lightyear, as defined by the International Astronomical Union, is the distance that light travels in a vacuum in one Julian year. It is equal to roughly 10 trillion kilometers (about 6 trillion miles). A lightyear is one unit used to measure distances on a galactic scale.
Filed under: Glossary
soundoff (No Responses)

Post a comment


  

CNN welcomes a lively and courteous discussion as long as you follow the Rules of Conduct set forth in our Terms of Service. Comments are not pre-screened before they post. You agree that anything you post may be used, along with your name and profile picture, in accordance with our Privacy Policy and the license you have granted pursuant to our Terms of Service.

« Back to main

Contributors

  • Elizabeth LandauElizabeth Landau
    Writer/Producer
  • Sophia DengoSophia Dengo
    Senior Designer
| Part of Part of CNN US