Only Known Sample of Metallic Hydrogen Suddenly Went Missing

Just a month later after achieving the so-called "holy grail of high-pressure physics," a team of researchers from Harvard announced that they have lost the only known sample of metallic hydrogen on Earth.

The sample, first describe in a paper published in the journal Science, was made when the researchers squeezed hydrogen between two diamond anvil at extremely high pressure. By testing the sample's reflective properties, the researchers observed that the squeezed hydrogen behaved just like what metals do during the test.

Initially, the researchers planned to transport their sample to the synchrotron at the Argonne National Laboratory. However, when the researchers tried to measure the pressure in the system once more using low-powered red laser, the system was immediately destroyed. This caused one of diamonds that holding the metallic hydrogen broke.

The researchers don't know if their sample survived or not. It is possible that it survived and is stable somewhere. Due to its size, which is around 1.5 micrometers thick and 10 micrometers in diameter, the researchers haven't been able to find its trace.

But, it is also possible that metallic hydrogen dissipated back to gas when the pressure of the diamond vice broke. If this is the case, the metallic hydrogen is not as stable as the researchers thought it would be under normal room pressure.

"Basically, it's disappeared," Isaac Silvera, natural sciences professor at Harvard and leader of the research team, told Science Alert. "We'd already tested it before, but evidently something changed over time. Perhaps defects developed in the diamond, perhaps there was diffusion of hydrogen. We don't know what happened."

Silvera noted that the sudden disappearance of the only metallic hydrogen sample on Earth does not question its validity. He and his team plans to recreate the sample using better synthetic diamond vices. Additionally, the researchers now know that it is not a good idea to keep the sample around for so long. Silvera hopes that when they successfully replicated their earlier success, they could do important measurements as quickly as possible.