From the epic Cosmos by Carl Sagan: amzn.to/2BKhUix (US). For UK: amzn.to/2BNeP14 | Canada: amzn.to/2AutZu2 | This short video clip shows Carl Sagan explaining the 4th Dimension. It is a short clip from Carl Sagan's Cosmos: A Personal Voyage. See also: universedvds.blogspot.com/p/cosmos-by-carl-sagan-all-episodes-on.html