A generation ago we knew of exactly one planetary system: our own. Today we've confirmed more than five thousand planets around other stars, and the count climbs every month. We explain the wonderfully indirect tricks astronomers use to find worlds they cannot see, what the "habitable zone" really means, and why finding a planet is a long way from finding life.

You'll come away understanding how a planet reveals itself by dimming or wobbling its star, why small rocky worlds are the hardest and most interesting to find, what makes a planet potentially habitable, and how we might one day sniff an alien atmosphere for signs of life.

Talking Science is sponsored by Kinsoft. Visit www.kinsoft.com.au

Further reading: NASA Exoplanet Exploration (exoplanets. ...