Aliens may be living among us, say two scientists, who argue we may even carry some alien genes. Australian researchers Professor Paul Davies and Dr Charles Lineweaver outline their hypothesis in the latest issue of the journal Astrobiology.They say the aliens in question are likely to be primitive microbes that sprang up some four billion years ago.At this time the Earth was being buffeted by a hail of meteors and giant asteroids during what's known as the Archaean bombardment.















