## Plus Advent Calendar Door #9: Is there anybody out there?

Submitted by Rachel on December 8, 2010Maths is the language of the universe: not only does it describe how the universe works, it also may be the secret weapon in the hunt for extraterrestrial life. And if we find them, maths might also provide the ideal way to break the ice with our little green friends from across the sky...

Hunting for life in alien worlds

Two of the most fundamental questions asked by people are how life emerged on the Earth, and whether we are alone in the cosmos. These deeply important questions form the core of a new kind of science, one that recently has been rapidly gathering momentum: astrobiology. You can also read more in Lewis Dartnell's excellent book Life in the Universe. And you can even hear Lewis talk about the science behind the latest aliens to hit the big screen in Monsters!

Life as we don't know it

Physicist and cosmologist Paul Davies is also doing research in astrobiology. He tells *Plus* about his interest in the big questions: what is life, how would we recognise aliens - and are they all around us?

Mathematics for aliens

It has often been observed that mathematics is astonishingly effective as a tool for understanding the universe. But why should this be? Is mathematics a universal truth, and how would we tell?

Games, Life and the Game of Life

When we finally meet the Martians, John Conway believes they are going to want to talk mathematics. He talks to *Plus* about his *Life* game, artificial life and what we will have in common with extraterrestrials.

Pi appears in crop circle

If these are alien calling cards, then we can be sure they are keen mathematicians.