It's easy to forget that we are on a pale, blue dot - the one habitable place we know of in the whole, wide, Universe. Fragile. Perhaps too fragile. It's not that the Universe wants to kill us; it's just that astrophysics doesn't care too much whether a planet is inhabited, or whether the inhabitants have feelings - or not. Asteroid strikes. Impact from a giant comet. Gamma ray bursts, supernovae, and black holes. Any one of these has the potential to destroy our civilisation. But how likely is that to happen? And what is there that anyone can do about it? If you enjoyed this episode, Death From Above - by Phil Plait - is an excellent resource. Join me as we talk about the potential for an apocalypse... from outer space!