How to measure the universe

[JMH]

Have you ever wondered how we know the distance between Earth and Proxima Centauri? What about the furthest reaches of the universe — how do we know they're the furthest? The Royal Observatory in Greenwich, London currently has an exhibition on the subject and has uploaded a video that gives a simple explanation of how astronomers deal with a very complex problem.

http://www.theverge.com/2012/6/16/3091197/how-to-measure-the-universe-royal-observatory-greenwich

 

[zigzag3143]

Great Find thanks.