Feedback is New Scientist’s popular sideways look at the latest science and technology news. You can submit items you believe may amuse readers to Feedback by emailing feedback@newscientist.com Doubling up If the internet is to be believed (it’s not), a growing proportion of celebrities have been replaced by clones. The latest to allegedly have their body snatched is actor Jim Carrey, star of Ace Ventura: Pet Detective and other cinematic miracles. Carrey attended the 51st César Awards in Paris on 26 February, his first public appearance for some time, and he looked a bit different compared with before. One might think that this would be attributed to some combination of ageing and cosmetic procedures, but instead, a conspiracy theory formed that the person wasn’t Carrey, but a clone. Whoever is doing all this celebrity body snatching, they are busy: Carrey’s replacement follows those of Paul McCartney (supposedly dead since 1966 and replaced by a stand-in) and Avril Lavigne (allegedly dead since 2003). You would think that, by now, they would have got better at concealing …