Goncharov has criticized the Silvera lab’s methods before. It’s far from clear that the shiny material the researchers see is actually hydrogen, says geophysicist Alexander Goncharov of the Carnegie Institution for Science in Washington DC. Seen through a microscope, the sample appeared shiny, and it reflected light in the way metallic hydrogen should do, he says. “Then, suddenly, it becomes a lustry, reflective sample, which you can only believe is a metal,” Silvera says. They then turned a screw to crank up the pressure to 495 billion pascals (495 GPa), or almost 5 million times higher than atmospheric pressure at sea level. They also say they have found a better way to polish the tips of their diamonds, to remove irregularities that could break the gems. To do so, they used an anvil that can fit inside a cryostat, enabling them to cool their hydrogen sample to just above absolute zero. Mikhail Eremets, who leads that group, says his team has not yet provided conclusive evidence.ĭias and Silvera say that they were able to squeeze their hydrogen gas at greater pressures than anyone else has managed. In 2011, a report by physicists at the Max Planck Institute for Chemistry in Mainz, Germany, was controversial. But no one has proven the existence of metallic, shiny hydrogen, which would reflect light. Researchers have seen the material change from transparent to dark as it is compressed, which suggests that as electrons are crowded together, they are able to absorb photons of visible light. The experiments are delicate and fraught with potential for error. In recent years, physicists have crushed tiny samples of hydrogen between diamond anvils at pressures exceeding those in the centre of Earth. And theorists say that the material could have other exotic properties, such as being a superconductor-able to conduct electricity without resistance-even at room temperature.īy making metallic hydrogen, physicists might also be able to explore planetary science at their lab bench: gas-giant planets such as Jupiter are theorized to have metallic hydrogen in their cores, which would perhap explain how they can sustain a magnetic field. When squeezed with enough pressure inside an anvil, hydrogen should be able to conduct electricity, the hallmark of a metallic state. ![]() ![]() Producing metallic hydrogen in the laboratory has been a dream of high-pressure researchers ever since 1935, when theorists first predicted its existence. Silvera and Dias say that they wanted to publish their first observation before making further tests on their fragile material. ![]() “I don’t think the paper is convincing at all,” says Paul Loubeyre, a physicist at France’s Atomic Energy Commission in Bruyères-le-Châtel. A peer-reviewed version of the report was published on 26 January in Science, but sceptics say that it includes little new information.įive experts told Nature’s news team that they do not yet believe the claim, and need more evidence. Ranga Dias and Isaac Silvera, both physicists at Harvard University in Cambridge, Massachusetts, first posted a report of their results on the arXiv preprint server last October, which attracted immediate criticism. Two physicists say that they have crushed hydrogen under such immense pressures that the gas became a shiny metal-a feat that physicists have been trying to accomplish for more than 80 years.īut other researchers have serious doubts about the claim, the latest in a field with a long history of failed attempts.
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