Santa Claus frolicking with penguins and polar bears--do you know what's wrong with this picture? Actually, no penguin has ever lived at the North Pole, nor any polar bear at the South Pole. Using a wide range of disciplines from physics to geography to biology, award- winning science writer Elaine Scott explores some of the unique properties shared by the two ends of the Earth's axis, and other ways in which they are poles apart. Find out what makes...