Metallic Hydrogen Discovery Met With Skepticism

Two Harvard researchers say they have synthesized a form of solid metallic hydrogen, a landmark scientific finding that could lead to the creation of “superconductors” and revolutionize the way electricity is conducted—but some scholars in the field remain skeptical.

Isaac F. Silvera and Ranga P. Dias, a Harvard physics professor and postdoctoral researcher, published a paper Jan. 26 in the journal Science describing the experiment. According to the paper, the researchers clamped hydrogen between two pieces of diamond, allowing the hydrogen to change from a gas to a solid.

“As we were pressing [the diamonds], we found that at lower pressures the sample is transparent,” Silver said. “When you get to about 4 million atmospheres it turns black and we’ve seen [black hydrogen] before. We continued to turn the pressure up and suddenly it became lustrous, reflecting like metal.”

After measuring the hydrogen’s reflectance, Silvera and Dias concluded that they had indeed created metallic hydrogen, a finding that has eluded high-pressure physicists for over 80 years.

Several leading figures in the high-pressure physics field, however, say they do not accept Silvera and Dias’s findings at face value. Because their experiment was not replicated, several researchers said, it should not have been published in one of the scientific field’s leading journals.

Mikhail Eremets, who studies metallic hydrogen at Max Planck Institute for Chemistry in Germany, said he was skeptical of the Harvard researchers’ discovery.

“The data were not reproduced, this basis of the scientific approach. This should be done first by the authors,” Eremets said. “In the present work there are not enough data and the quality of data is very poor. Papers with such data cannot be published in any scientific journal.”

Eugene Gregoryanz, a high-pressure physicist at the University of Edinburgh in Scotland, said he agrees with Eremets.

“There are no raw data presented in the paper. The main paper presents 3 iPhone photos and the claimed reflectivity measurements (not raw but processed data) at the last pressure point,” Gregoryanz wrote in an email. “I do not think the major scientific discovery can be presented with the iPhone photos and without any raw data coming from hydrogen.”

Both Eremets and Gregoryanz also said they were concerned about the way the Harvard researchers took the pressure measurements and the methods used to determine whether the material was a metal.

Silvera, however, defended his findings, and said that his research methods were scientifically sound. He added he is confident that if the experiment were conducted again, he would receive the same results.

“You can be skeptical and say you should measure more samples. How many samples do you want to measure?” Silvera said. “We’ve made a very important discovery and advance for high pressure physics. We wanted to publish it at that point and make it known and available to the public.”

Silvera said that the research team will soon transport the sample to Illinois, where they will use X-rays to determine the crystal structure of the metallic hydrogen.