The magical science behind the 'supermoon' eclipse

People around the world have been watching the skies to observe a rare celestial event, as a lunar eclipse coincides with a so-called "supermoon".

A supermoon occurs when the Moon is in the closest part of its orbit to Earth, meaning it appears larger in the sky.

Keith Cowing, editor of nasawatch.com in Washington, explains the reasons for the unusual phenomenon, which will happen next in 2033.