# 50

 When Number story first landed on my desk I was struck by its prettiness. With its tasteful and slightly old-fashioned cover design, the unusually compact format for a hardback, and the unassuming title, this book clearly isn't desperate for attention. So I was intrigued to find out whether this quiet confidence is justified by its content, and I'm glad to report that it is. The Magic Numbers of the Professor revolves around a fictional professor and a huge range of magical numbers. Written in a narrative style, the book documents a series of visits the Professor makes from America to Ireland to visit Owen O'Shea, the author of both this book and a fictional column within the story. It's International Year of Astronomy and all eyes are on Galileo Galilei, whose astronomical observations 400 years ago revolutionised our understanding of the Universe. But few people know that Galileo wasn't the first to build a telescope and turn it on the stars. That honour falls to a little-known mathematician called Thomas Harriot, who excelled in many other ways too. Anna Faherty takes us on a tour of his work. As an electronic musician 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. Describing the motion of fluids is a huge and unsolved mathematical problem. There are equations that seem to describe it well, but their complete solution is way beyond reach. But could there be a simpler method? The physicist Jerry Gollub tells Plus about a new discovery which combines experiment with sophisticated maths. The prime numbers are the atoms amongst the integers, and while we know that there are infinitely many of them, there's no general formula that generates them all. Julian Havil looks at a little-known algorithm that sieves out all primes up to a given number, and which is astonishing in its simplicity. In 1979 decorating work in a house in Vienna revealed a set of medieval frescoes depicting a cycle of songs by a 13th century poet, who was particularly fond of satirising the erotic relationships between knights and peasant maidens. The frescoes are of great historical significance, but they are badly damaged. In this article Carola Schönlieb explores how mathematicians use the heat equation to fill in the gaps.