Scientists At Harvard University Claim They Have Created Metallic Hydrogen – A Material That, Until Now, Existed Only In Theory

Metallic hydrogen was a ghost material, predicted theoretically in 1935 by two physicists, Eugene Wigner and Hillard Bell Huntington. The two scientists came to a conclusion that, under a colossal pressure hydrogen atoms could display metallic properties, but all predictions stayed just a theory because the amount of pressure needed to transform hydrogen into a metal was just too high to be recreated artificially back then.

The hypothesis predicts that, although the material can’t be found on the Earth, metallic hydrogen could exist inside cores of gas giant planets such as Jupiter, Saturn, Neptune, Uranus, and a number of extrasolar planets. Inside enormous gas giants, metallic hydrogen would exist in liquid form, and although not being solidified, it behaves like an electrical conductor.

The material became “the holy grail of high-pressure physics,” with a couple of experiments trying to recreate high-pressure conditions and to create metallic hydrogen. All of them failed, until 2016 when a group of scientists of the Lyman Laboratory of Physics at Harvard University stated they managed to synthesize solid metallic hydrogen in the laboratory.

The study got published in Science, managing to gather huge interest. The two physicists, Professor Isaac Silvera and Dr. Ranga Dias, used pressures of 495 GPa, more than is found at the center of the Earth, (the first theory predicted that hydrogen would behave as an electrical conductor under a pressure of 25 GPa) and managed to observe metallic hydrogen in solid form.

Images of the stages in the creation of metallic hydrogen: Transparent molecular hydrogen is on the left, created at about 200 GPa, black molecular hydrogen is in the middle, with reflective atomic metallic hydrogen created at 495 GPa. Image Courtesy of R. Dias, I. F. Silvera

“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,” they stated. The new material was crushed under a diamond clamp, and is observable, although it is still trapped under an immense pressure. There are plans to gradually ease the pressure, ultimately freeing the material, in the course of the next couple of weeks.

If metallic hydrogen ends up being stable under normal pressure and room temperature, it could become the most valuable material on Earth. Since it features properties of a superconductor, the newly found material could tremendously affect our economy and technology. It could be used in power grids since “As much as 15 per cent of energy is lost to dissipation during transmission, so if you could make wires from this material and use them in the electrical grid, it could change that story.”

Also, the material could be used as a super-efficient rocket fuel, enabling our civilization to explore our solar system. “It takes a tremendous amount of energy to make metallic hydrogen,” Professor Silvera said, “And if you convert it back to molecular hydrogen, all that energy is released, so it would make it the most powerful rocket propellant known to man, and could revolutionize rocketry. That would easily allow you to explore the outer planets. We would be able to put rockets into orbit with only one stage, versus two, and could send up larger payloads, so it could be very important.”

Not all is bright, though. Shortly after the research got published, Nature contacted some experts and published a paper with them showing disbelief for the claims the two scientists from Harvard University made.

The main problem is the fact that the material is still crushed between jaws of the diamond anvil, and that the whole paper is based on circumstantial evidence since no direct observation has been done. Also, one of the physicists claiming to have discovered the new material, Isaac Silvera, said that, when looked through the microscope the material looks shiny and that “you can only believe [it] is a metal.”

But, other scientists explained that the sample observed doesn’t have to be metal at all. The shininess could come from aluminum oxide, known for coating diamonds (like ones used in the anvil used for creating metallic aluminum), and becoming shiny under pressure.

Another point of doubt is the amount of pressure created. There are reasons to believe the two Harvard researchers didn’t take precise enough measurements, making it possible that the amount of pressure created wasn’t high enough to create metallic hydrogen.

And the most defensible question is why the paper got published before the material got out of the anvil, because the results may greatly differ once you observe the results first hand.

Isaac Silvera and Ranga Dias answered by saying that they have publicized the paper because results were revolutionary and that they will conduct further experiments that should confirm their findings.

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