Build a mega Menger!
Help to build the world's largest distributed fractal!

Maths takes flight
Soon you will be able to step inside a mathematical space and experience the beauty and importance of maths!

In a lower dimension
Could the world be simpler than our senses suggest?

Constant worries
What makes a number a constant of nature?

Why do mathematicians play games?
Why game theory is a serious business.

The maths of magic squares
How to create a magic square of any size, and even of any dimension!

Making a right angle the Maya way
The Mayan civilisation brought forth many great things — including this clever way of making a right angle.

Too big to write but not too big for Graham
Meet the number that's bigger than the observable Universe!

The art of guessing
How to avoid tedious calculations.

Did chaos cause mayhem in Jurassic Park?
Was T-rex unleashed by mathematical chaos?

What is information?
Books, brains, computers — information comes in many guises. But what exactly is it?

This August we were lucky enough to attend the International Congress of Mathematicians in Seoul, South Korea. We talked to the winners of the prestigious Fields Medals, as well as many other fascinating mathematicians. Here's a selection of articles and podcasts from the congress. You can see our full coverage here.

Answers on a donut
We enjoyed Manjul Bhargava's Fields medal lecture so much we wanted to share it with you, so here is an abridged version. You can also read our interview with Bhargava and listen to it in our podcast.

Artur Avila: taming chaos
Artur Avila is received a Fields Medal for his "formidable technical power, the ingenuity and tenacity of a master problem-solver, and an unerring sense for deep and significant questions." You can also listen to an interview with Avila in our podcast. 

Martin Hairer: at the interface
Martin Hairer received his Fields Medal for a major breakthrough that gives a way of attacking problems that had previously been impenetrable. You can also listen to an interview with Hairer in our podcast.

Maryam Mizharkani: counting curves
Maryam Mirzakhani received a Fields Medal for her "rare combination of superb technical ability, bold ambition, far-reaching vision, and deep curiosity".

Stanley Osher: connecting the disconnected
Stanley Osher won the 2014 Gauss Prize for his revolutionary impact in areas including medical imaging, sonic booms, movie animation and microchip design and manufacture.

We've all made embarrassing mistakes, but one of the most embarrassing mistakes ever made has to be this one. On September 23, 1999 the Mars Climate Orbiter entered its target orbit around Mars, from where it was to observe the red planet's climate and atmosphere for one Martian year. It duly disappeared behind Mars a few minutes later, but it never re-appeared on the other side. A week later NASA officially gave up on the spacecraft. A "mishap investigation report" later concluded that the $193 million Orbiter had entered into orbit at a much lower altitude than planned and as a result it either disintegrated in the atmosphere or sped off to orbit the Sun.

Embarrassingly, the error was a result of a confusion about units: Lockheed-Martin, the company who operated the spacecraft for NASA, used Imperial units of measurement — miles, feet and pounds — while NASA's team used metric ones. It was Lockheed-Martin who were out of step with the rest of the world on this.

The failed mission illustrates what travellers have known for centuries: different units are confusing. Although some countries insist on odd units of measurements out of pure pig headedness, it's clear that a universal standard is what's reasonably required. The question is what to base this on. Many traditional units use the dimensions of the human body — the length of feet, fingers and so on — but these are clearly too variable to give a consistent definition.

This is why the modern International System of Units (SI units), which Lockheed-Martin chose to ignore, ties the definition of a metre to something a lot more constant: the speed of light in a vacuum. In 1983 the metre was defined as

"the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second."

This of course requires a rigorous definition of a second. As you may have guessed, it is no longer defined as 1/(60 x 60 x 24) = 1/86,400 of a day but as


"the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom".

This may sound rather convoluted, but it's all in the name of precision which, as our favourite embarrassing mistake illustrates, is important.

This is one of the fascinating stories that didn't make it into our book, Numericon: a journey through the hidden lives of numbers.