Phil Wilson continues our series on the life and work of Leonhard Euler, who would have turned 300 this year. This article looks at the calculus of variations and a mysterious law of nature that has caused some scientists to reach out for god.

Plus 1000 — Mathematical lives

Plus celebrates its 10th birthday!

Mathematicians solve the famous loop's mystery

A new Bayesian network helps predict the severity of the disease

A new mathematical model explores the time before the big bang

Graph theory helps answer Sudoku questions

Computer scientists prove how long it should take you to solve Rubik's cube

Plus celebrates its tenth birthday this year. Former editor and present executive editor of Plus, Robert Hunt, explores how maths popularisation in general, and Plus in particular, have changed over the last ten years.

Geometry is power

One of the many strange ideas from quantum mechanics is that space isn't continuous but consists of tiny chunks. Ordinary geometry is useless when it comes to dealing with such a space, but algebra makes it possible to come up with a model of spacetime that might do the trick. And it can all be tested by a satellite. Shahn Majid met up with Plus to explain.