Hydrogen is a light, explosive gas at Earth’s atmospheric pressures, but in the centre of a gas giant such as Jupiter, scientists believe it exists in a metallic, superconducting phase.
Metallic hydrogen is thought to play a vital role in the inner workings of gas giants. In the centre of a gas giant, at pressures of over 4,500 million times the atmospheric pressure of Earth, hydrogen is metallic and is thought to be able to conduct electricity with zero resistance. In January, Physicists at the University of Edinburgh came close to recreating this phase on Earth, by compressing a micron cubed of hydrogen between two diamonds to pressures up to 4 million times atmospheric pressure. Some bonds still remained, so this phase is called ‘phase V’.
They used diamond anvil cells, which would fit in the palm of your hand. Two diamonds are held in a metal frame which is tightened to push the tips closer together, compressing the hydrogen trapped between them. At the high pressures reached, the diamond is weakened so it can easily crack. The diamonds last for nanoseconds before they break, giving the researchers little time to gather data to prove that the compressed hydrogen is conducting.
At the pressures created, many analytical techniques don’t work. The properties of phase V hydrogen were measured using Raman spectroscopy, which studies the scattering of light when it interacts with the molecular vibrations. The space between the diamonds is so small that electrodes can’t be used to test the conductivity, so it is not yet known whether the phase is superconducting (able to conduct electricity with zero resistance) as predicted.
If a metallic phase of hydrogen is created and characterised, this would give scientists useful data about planet formation and could explain why huge planets like these are closer to their stars than current solar system models predict. If it can exist at ambient temperature and pressure, it could even be used to make ultra-fast computers, or rocket fuel with a much greater power output than the hydrogen which is currently used.
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