Experts consider this novel state of hydrogen a “holy grail” of solid state physics for its potentially world-changing applications, from big bang-for-your-buck rocket fuel to ideal electric wires.
In any environment humans could survive, hydrogen exists as a gas. But just as water can transform into ice at low temperatures, hydrogen gas, like most substances, can become liquid or even solid if you cool it or squeeze it enough.
The key to the alchemy of hydrogen is pressure. By definition, metals share electrons that can flow freely throughout the substance, which is why metal spoons get hot while wooden spoons don’t. This property also makes them good at carrying electricity, as well as heat.
To get hydrogen to perform this trick, scientists had to squeeze the atoms so hard that electrons got knocked loose from their original atoms, becoming free to move around.
But achieving such high pressures isn’t easy. Early estimates predicted that hydrogen would become metal at 250,000 times the atmospheric pressure of sea level, but as scientists devised ever craftier experiments, the goal kept receding just out of reach.
It's a question that can only be answered experimentally, and scientists around the world have been racing to create the exotic form of hydrogen in the lab.
“If you look at the literature for the last 30 years,” Eugene Gregoryanz, a physicist at the University of Edinburgh, previously told Science News, “I think every five years there is a claim that we finally metallized hydrogen.” Skepticism surrounding this latest announcement is high, too. At least five experts already told Nature they don’t believe the claim.
But eveof at least four forms of solid hydrogen, one as recently as 2011, and a 2015 experimn mistaken claims move the field forward. In the last 40 years, physicists have learned ent led to a record-breaking new superconductor.
Two physicists claimed that they had finally succeeded in a feat that scientists have been attempting for almost a hundred years – crushing hydrogen and turning it into metal through space travel, and has been hailed as one of the biggest breakthroughs in history.an “alchemical” process. Such a discovery would potentially revolutionise technology and
But experts have cast doubts on the claims of the two scientists, Ranga Dias and Isaac Silvera, both physicists at Harvard University. They might have mistaken something else for the important metal, a number of other scientists have said.
But the paper was published this week in the journal Science all the same, heralding a succession of headlines that claimed that humanity had made a huge breakthrough that could shed light on some of the central questions of the universe. The news was covered in a range of newspapers and websites.
But five different experts have told Nature's news reporters that they don't believe the claim and that it could be based on an error.
That is what the two Harvard scientists claimed to have done. But they cannot yet show off the piece of metal because it is still stuck between the jaws of the anvil – and they say that removing it might cause it to disappear entirely.
The researchers believe however that the reflective and shiny material they can see crushed in the anvil is metallic hydrogen. One of the scientists, Isaac Silvera, said that when looking through a microscope at the sample it looked to be shiny and so “you can only believe it is a metal”.
But other researchers have said that they don’t necessarily believe that it is a metal. The shininess may be something else entirely – like aluminium oxide, which is known to coat the diamonds that sit in the anvil and may become shiny under high pressure.
