How does something made of loose particles sometimes behave like a solid, liquid or gas? For example, dry sand acts like a solid when you stand on it but like a liquid when you try to scoop some up in your hand.

Or how Saturn's rings act like a fluid.    Dr Nikolai Brilliantov from the University of Leicester Department of Mathematics is intrigued by the maths of things like that and is going to give a free lecture on February 15th in the University’s Ken Edwards Building, Lecture Theatre 1, at 5.30pm titled ‘Statistical mechanics of granular matter: simple concepts and complex phenomena’.

The rings of Saturn are made up of millions of rocks which behave like the molecules in a gas.  Brilliantov has made a special study of the outermost ring, which is unusual because it is composed of ice crystals.

NASA Cassini mission showed that these ice crystals all come from giant fountains on Enceladus, one of Saturn’s larger moons. Brilliantov’s mathematical work seeks to show precisely how the ice thrown out from Enceladus is able to form over time into a giant ring encircling the whole planet.

“I find it amazing how mathematicians who have never looked into a telescope can quantify phenomena which are billions of miles apart,” says Dr Brilliantov. “Moreover, they can say with confidence: there is liquid water on this small moon and it was there for the last few millions of years!”