Shedding light on the deepest depths of the universe is Gerry Gilmore, who talks about the Big Bang and the mystery of dark matter. We also hear from Peter Muller and Giulio del Zanna about 3-D imaging of the surface of Mars and how solar flares contribute to everything from the Northern Lights to damaging communication systems. David Block describes how Andromeda, the galaxy closest to the Milky Way, was recently involved in a galactic collision, and in case you fancy seeing some collisions here on Earth, Derek and Dave are in the kitchen making meteorite craters. Like this podcast? Please help us by supporting the Naked Scientists)