## Articles

*Second Life*it may seem as if reality has become a whole lot bigger over the last few years. In one branch of theoretical physics, though, things seem to be going the other way. String theorists have been developing the idea that the space and time we inhabit, including ourselves, might be nothing more than an illusion, a hologram conjured up by a reality which lacks a crucial feature of the world as we perceive it: the third dimension.

*Plus*talks to

**Juan Maldacena**to find out more.

**Ben Allanach**investigates.

**David Spiegelhalter** and **Mike Pearson** explore how risk can be spun and there's an interactive animation for you to have a go yourself.

**Jerry Gollub**tells

*Plus*about a new discovery which combines experiment with sophisticated maths.

**Oli Freke**has always been fascinated by sine waves, so much so that he's created a song based on them for the Geekpop festival, which is currently taking place on the Web. In this article he explores his song, touching on ancient Greek mythology, strange piano tunings and Johann Sebastian Bach.

**Carola Schönlieb**explores how mathematicians use the heat equation to fill in the gaps.

**Colva Roney-Dougal**explores the maths, from chaos to group theory.