According to Euclidean geometry the angles of a triangle add up to 180 degrees. Philip Morrison shows an example of where this isn't true, and non-Euclidean geometry applies. Watch the full lecture: http://www.rigb.org/christmas-lectures/watch/1968/gullivers-travels/the-world-of-captain-gulliver?utm_source=youtube&utm_medium=social&utm_term=description Philip Morrison's Christmas Lectures in 1968 focussed on the importance of scale in science. Taking inspiration from Dean Swift's Gulliver in the lands of Lilliput and Brobdingnag , we go on a journey from the fundamental building blocks of the universe to the stellar size of of our galaxy. In the first lecture we examine some of the smallest and largest objects ever made by man. Among the topics covered are the simple artihmetic of large and small numbers, geometry of size itself, and the nature of length, area, and volume. Watch the full series: http://www.rigb.org/christmas-lectures/watch/1968/gullivers-travels?utm_source=youtube&utm_medium=social&utm_term=description The Ri is on Twitter: http://twitter.com/ri_science and Facebook: http://www.facebook.com/royalinstitution and Tumblr: http://ri-science.tumblr.com/ Our editorial policy: http://www.rigb.org/home/editorial-policy Subscribe for the latest science videos: http://bit.ly/RiNewsletter