Will the orbits of the planets ever go haywire? Mr. Newton, meet chaos theory.

By Greg Laughlin

THE WORLD FACES daunting problems - climate change, recession, reality TV shows - but by "world", we usually mean the film of life coating its surface, not the planet itself. We take for granted the clockwork stability of planetary orbits. Nobody worries that Mercury will run rampant in the inner solar system. There's no serious concern that Mars will smash into Earth. After all, the planets have been stabling circling the Sun for the last 4.54 billion years. If anything could go wrong, you'd think it already would have.

... and yet ...

Read the rest of this article in the May/June issue of Australian Sky & Telescope.