London: Lord Martin Rees, the Astronomer Royal of the UK, says aliens could be amongst us and we may not be able to recognise them.
"They could be staring us in the face and we just don``t recognise them," the Sun quoted him, as saying.
Rees, who is also the President of the Royal Society, continued: "The problem is that we``re looking for something very much like us, assuming that they at least have something like the same mathematics and technology.
"I suspect there could be life and intelligence out there in forms that we can``t conceive.
"Just as a chimpanzee can``t understand quantum theory, it could be there are aspects of reality which are beyond the capacity of our brains."
Rees, 67, was speaking shortly after hosting the first conference on the possibility of alien life in the Royal Society``s 350-year-history.