Signup for your FREE trial to The Great Courses Plus here: http://ow.ly/UJHp30rFZvu Could it be that the universe does not expand but we shrink instead? What does it mean that the universe expands anyway? And if it does, what does it expand into? In this video I tell you what you need to know about Albert Einstein's General Relativity to make sense of all this. Correction to the illustration at 3 mins 31 seconds: It should just have been "smaller than 2 Pi R", not "R smaller than 2 Pi R" (which is correct, but makes no sense). Sorry about that! Correction to what I say at 6 mins 40 seconds: It's been brought to my attention that in 1992 it was proved one needs in general only 8 dimensions, not 10, see https://en.wikipedia.org/wiki/Whitney_embedding_theorem You can support us on Patreon: https://www.patreon.com/Sabine 0:00 Intro 0:54 How General Relativity works 5:52 What does the universe expand into? 7:01 Do we expand with the universe? 7:39 Do we shrink? 8:58 Summary 9:38 Sponsor Message #physics #space #universe