Scientists harnessed pressures greater than those found at the centre of the earth to turn hydrogen into a metal that could be extremely efficient at conducting electricity.

The breakthrough, which created a material that has never existed before, has been hailed as "the holy grail of high-pressure physics".

Metallic hydrogen is highly prized because of its potential as a room-temperature superconductor.

Image: Stages in the formation of metallic hydrogen from molecular hydrogen. The new material could have applications in medicine, transport, electrical engineering and space exploration. Pic: Isaac Silvera

It could find its way into next-generation MRI scanners, replacing the huge, energy-intensive, super-cooled superconductors to make the medical imaging system more affordable and practical for hospitals around the world.

The material could also have a range of other uses from electronics and electric cars, through to the generation and storage of electricity.


The huge forces used to form the metal could also be used, in theory, as a propellant for much more powerful and efficient space rockets.

Harvard physicist Isaac Silvera said: "This is the Holy Grail of high-pressure physics.

"It's the first-ever sample of metallic hydrogen on Earth, so when you're looking at it, you're looking at something that's never existed before."

Details of the research, which is the first confirmation of a long-standing theory that hydrogen, normally a gas, could occur in a metallic state if exposed to extreme pressure, was published in the journal Science.

Professor Silvera and his fellow scientist fellow Ranga Dias squeezed a sample of frozen hydrogen to nearly 72 million pounds per square inch, which is greater than the pressure at the center of the Earth.

They created the immense force using synthetic diamonds mounted opposite each other in a device known as a diamond anvil cell.

However, a key question remains whether the pressurised hydrogen maintains its metallic properties at room temperature, which would make it very useful as a superconductor.

Both scientists believe it will, but this still has to be proved.