Someone at the Independent is worried that SETI could be a risky business – what if looking for alien civilisations is an open invitation for them to wipe us out? George Dvorsky takes a more rational viewpoint, namely that if aliens wanted to destroy us, they would have done so already, ergo SETI is safe (if pointless).

At least we’re a little closer to dicovering the truth behind the Tunguska event, as an Italian team have discovered what they believe to be the impact crater of the asteroid that caused it – as opposed to the crashed flying saucer that has been posited by others. But who knows – maybe we really were visited, or even created, by an alien race – one that saw fit to scribble graffiti in our DNA?