Johannes Kepler (1571-1630) is now chiefly remembered as a mathematical astronomer who discovered three laws that describe the motion of the planets. J.V. Field continues our series on the origins of proof with an examination of Kepler's astronomy.

• Darkened skies
• Interesting times

If boomerangs are really gyroscopes, then what are gyroscopes? In this article, we explore some more of the physics of gyroscopes, and demonstrate some interesting experiments you can do with them.

Starting in this issue, PASS Maths is pleased to present a series of articles about proof and logical reasoning. In this article we give a brief introduction to deductive reasoning and take a look at one of the earliest known examples of mathematical proof.