HARD PRESSED

Not only would making metallic hydrogen in the laboratory allow researchers to do planetary science at the bench - gas-giant planets such as Jupiter, or the even larger ones being discovered around distant stars, are thought to have huge amounts of the stuffin their interiors - but it could point the way towards an entirely new world of high-pressure phenomena. [...]Hemley says that in his own experiments with hydrogen at similar pressures, "we see it transmitting" in the infrared. [...]in a paper published in April7, Hemley and his colleagues report signs that hydrogen squeezed up to 360 GPa holds on to its diatomic character and fails to morph into a monatomic metal.