In science fiction films, aliens normally look either like slightly weird humans - or slimy creatures with horrible, wriggly appendages.
But it’s more likely that we’ll encounter a race of machines, the Astronomer Royal has warned.
Sir Martin Rees believes that, as technology advances, most races will ‘transform’ from being organic creatures into being immortal robots - and it’s these we’re likely to meet.
‘This suggests that if we were to detect ET, it would be far more likely to be inorganic: We would be most unlikely to “catch” alien intelligence in the brief sliver of time when it was still in organic form.’
Sir Martin believes that in a few hundred years, human beings will, likewise, turn into robots.
He also suggests, writing in Nautilus magazine, that aliens may be so god-like that we’re currently looking for the wrong sort of signal.
He writes, ‘Searches for extraterrestrial intelligence typically seek some electromagnetic transmission that is manifestly artificial. But even if the search succeeded (and few of us would bet more than 1 percent on this), it would still in my view be unlikely that the “signal” would be a decodable message.
‘It would more likely represent a byproduct (or even a malfunction) of some super-complex machine far beyond our comprehension that could trace its lineage back to alien organic beings (which might still exist on their home planet, or might long ago have died out). The only type of intelligence whose messages we could decode would be the (perhaps small) subset that used a technology attuned to our own parochial concepts.’