'Nasa's Kepler telescope scans the skies for 'habitable worlds' - but an American chemist has suggested the whole project might be a terrible idea.

Ronald Breslow suggests that life-forms based on slightly different amino acids and sugars could take the form of huge, ferocious dinosaurs that have evolved to have human-like intelligence and technologies.

'We would be better off not meeting them,' says Breslow, who claims that it was a stroke of luck that an asteroid wiped out dinosaurs on earth, leaving the field clear for mammals such as humans.'

Read more: Welcome to Our New Lizard Overlords: Study Suggests Alien Worlds Could Be Full of Super-Intelligent Dinosaurs