This week, we're examining NEOs - near-Earth objects - asking whether any of them might be on a collision course with our biggest cities... Like this podcast? Please help us by <a href="https://www.thenakedscientists.com/donate">supporting the Naked Scientists</a>

New part of the immune system, and greedier labradors

The Naked Scientists flagship science show brings you a lighthearted look at the latest scientific breakthroughs, interviews with the world's top scientists, answers to your science questions and science experiments to try at home.