A team of theoretical physicists at the University of St Andrews in Scotland, who not too long ago showed that invisibility cloaks were possible, has worked out a way to reverse the pheneomenon known as the Casimir force – which causes objects to stick together – so that it repels instead of attracts. The discovery could ultimately lead to frictionless micro-machines with moving parts that levitate. And they say that in principle that effect could be used to levitate people. Which of course will lead to hoverboards like the ones in Back to the Future. (Telegraph; t/y Ross)