## 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.

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

**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.

**Jerry Gollub**tells

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

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

**Angus Brown**looks at one of these, a simple model for option pricing, and explains how it takes us on the road to the famous Black-Scholes equation of financial mathematics, which won its discoverers the 1997 Nobel Prize in Economics.

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