'The common belief that rocket science is difficult - as evidenced by the expression 'it's not rocket science' - is false,' according to Dr Margaret Mosel of Oxford University. 'Our research found the science is not hard at all. Working out which is the cheaper train ticket to buy is much more intellectually demanding.'
NASA rocket scientist Professor Joe Burns disagrees.
'Doing the countdown to launch is very complex, involving the ability to count backwards from ten to zero,' he said. 'Then there's the blue touch paper to manage. Rocket science is definitely tough stuff.'
But OED researcher Dr James Levies believes the use of the phrase 'it's not rocket science' will now gradually die out.
'And to work out why isn't rocket science,' he said.