## Frontiers of physics

In the previous article we explored how a clever argument involving gambling makes the idea that there are parallel universes more credible. But does it really?

Are there parallel universes? 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 spoke to physicists Adrian Kent and David Wallace to find out more. Happy reading!

String theory predicts there are more than the familiar four dimensions of space-time. But where do those extra dimensions come from? Eva Silverstein is looking for the answer.

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.

A bizarre set of of 8-dimensional numbers could explain how to handle string-theory's extra dimensions, why elementary particles come in families of three... and maybe even how spacetime emerges in four dimensions.

Space is three-dimensional... or is it? In fact, we are all used to living in a curved, multidimensional universe. And a mathematical argument might just explain how those higher dimensions are hidden from view.

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 asked theoretical physicist David Berman to find out more. We also bring you a range of other *Plus* articles exploring the question, as well as two articles from FQXi who are our partners on this project. Happy reading!

String theory has one very unique consequence that no other theory of physics before has had: it predicts the number of dimensions of space-time. But where are these other dimensions hiding and will we ever observe them?

Does infinity exist? 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 speak to cosmologist John D. Barrow to find out more. We also bring you a range of other *Plus* articles on the subject of infinity, as well as an article from FQXi who are our partners on this project. Happy reading!