The idea that extraterrestrial organisms have throughout time seeded the surface of the Earth is not the sole preserve of loonies, mystics, conspiracy theorists, the permanently stoned and various wishful thinkers. This idea of panspermia has some pretty high profile and serious adherents. Perhaps one of the most surprising was the renowned but controversial astrophysicist Sir Fred Hoyle; pillar of the scientific community for much of his life, atheist, Darwinist and the man who coined the term Big Bang, albeit as a way of disparaging it. Yet also a man who believed that the global 1918 flu pandemic, polio and HIV were each the result of micro-organisms that fell from the skies rather than developing here on Earth. The broader scientific community dismisses such thinking because it derives in part from either an incredulity at the processes involved – as was the case with Hoyle – or an ignorance of them.