Brought to you by http://www.allthingsscience.com/nWorld famous astronomer and astrophysicist, the great Carl Sagan, explains the 4th dimension....
La 4ème dimension par Carl Sagan...
http://www.CarlSaganVideos.com Physics: The 4th Dimension...
30-second Sci-Fi Book Review #80 See all my reviews here http://t.co/uErqTdnD6l...