Most of us are aware that Einstein proved that everything was relative ... or something like that. But we go no further, believing that we aren't clever enough to understand what he did. **Hardeep Aiden** sets out to persuade readers that they too can understand an idea as elegantly simple as it was original.

What do computers and light switches have in common? **Yutaka Nishiyama** illuminates the connection between light bulbs, logic and binary arithmetic.

In the last issue **Lewis Dartnell** explained how chaos on the brain is not only unavoidable but also beneficial. Now he tells us why the same is true for our solar system and sends us on a journey that has been travelled by comets and spacecraft.

Physicist and cosmologist **Paul Davies** has made an unusual move into the infant discipline of 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?

Riaz Ahmad's mathematical career has led him from the complexities of blood flow to the risks of the financial markets via underwater acoustics. *Plus* found out how maths can explain all this and more.