It was found at pressures 3.25 million times that of Earth’s atmosphere.
Metallic hydrogen — it is an elusive and mysterious material that is found in very large quantities inside both Jupiter and Saturn. It was first predicted to exist back in 1935, however attempts to recreate it in the lab had been unsuccessful. But now scientists are one step closer.
They found that, under certain conditions, hydrogen enters a never-before-seen phase, known as Phase V, which exhibits some interesting properties — molecules begin to separate into single atoms, while the atom’s electrons begin to behave like a metal. In nature, pairs of hydrogen atoms bond to form the molecule H2. However with enough pressure, the bonds break, allowing electrons to flow freely.
“Our study presents the first experimental evidence that hydrogen could behave as predicted, although at much higher pressures than previously thought. The finding will help to advance the fundamental and planetary sciences,” says lead researcher Eugene Gregoryanz from the University of Edinburgh.
So how much pressure did they have to apply to the hydrogen molecules for them to act this way? Over 380 GigPascals! For comparison, 1 GigaPascal is equivalent to nearly the pressure of 10,000 Earth atmospheres. That is almost impossible to imagine. This is not only the highest pressure ever applied to hydrogen molecules, it is also one of the highest pressures ever achieved in a laboratory setting.
This immense pressure, caused by slowly compressing hydrogen molecules between two diamonds anvils, changed the chemical bonds of the hydrogen molecules causing them to enter this new solid phase, Phase V. This phase is the what scientists are calling the early stages, since they have not yet achieved a fully metallic state of hydrogen. They believe applying an even higher pressure could result in a pure metallic state — however diamond anvils may not be up to the task.
If that’s true, scientists will have their work cut out for them to figure out what material can.
This is not the first time that scientists have claimed to achieve metallic hydrogen. Back in 2012, researchers in Germany said they had found evidence of a metallic state, however according to Ivan Amato at the time, “high-pressure experiments are fraught with the potential for error.” The claim was later disproved. So we can assume these results are also going to be met with heavy skepticism and criticism.
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