“There’s no logical reason to believe that machine intelligence won’t, in fact, inherit the Earth, and perhaps inherit the Universe,” said cosmologist David Grinspoon, referring to Ray Kurzweil’s idea of the coming merger of human and machine.

“And you can certainly imagine, even if it doesn’t happen here, that on some planet intelligent machines have been created which are effectively immortal. In fact, I think that it’s hard to argue the opposite…. When we consider the entire spectrum of possibilities with evolution of extraterrestrial intelligence, we do have to consider the existence of quasi-immortal machine civilizations out there.

“And one intriguing possibility is that when we do receive a signal … we may not know if it comes from a machine or from a biological entity.”