How many dimensions are there? In the latest online poll of our Science fiction, science fact project you told us that you'd like an answer to this question. So we went to see theoretical physicist David Berman to find out more. He explains that, although we might not initially think of it this way, we are actually used to living in a curved, multidimensional universe. String theory predicts that the Universe is ten-dimensional and a mathematical argument from the 1960s might just explain how those higher dimensions are hidden from our view.
You can read the articles that accompany this podcast: Kaluza, Klein and their story of a fifth dimension and The ten dimensions of string theory . And don't forget to vote for the next question you'd like to have answered!