It was said to have been the only piece on Earth of a metal that could have revolutionised life as we know it.
But a tiny sample of metallic hydrogen – purportedly created by scientists at Harvard University – has disappeared, The Independent can reveal.
According to one theory, the metal would be a superconductor capable of dramatically improving anything to do with electricity, creating faster computers, saving vast amounts of power currently lost in transmission and ushering in a new generation of super-efficient electric vehicles.
It could also be used to make a much more powerful type of rocket fuel, enabling humans to explore the solar system as never before.
The minuscule sample was being kept between two tiny diamonds at a pressure greater than found at the centre of the planet and a temperature close to absolute zero, while its properties were studied.
But an attempt to measure the pressure using a low-power laser went disastrously wrong with a small “click” indicating that one of the diamonds had shattered into a fine dust.
Saying “my heart fell” when he heard the news, the lead researcher, Professor Isaac Silvera, revealed this catastrophic failure had resulted in the loss of the sample.
“I’ve never seen a diamond shatter like that. It was so powdered on the surface, it looked like baking soda or something like that,” he said.
“I didn’t believe it was diamond, it was such a fine powder.”
There are a number of possible explanations for the lack of any evidence of metallic hydrogen in the remains.
It could be that the tiny sample is lost somewhere within the metal ‘gasket’ used to contain it between the crushing pressure of the diamonds.
It might also mean that metallic hydrogen is unstable and turns into a gas when it is at room temperature and normal pressure, in what would be a major setback for any hopes of a new wonder material.
But a number of physicists have also claimed that the sample was never actually created in the first place.
Writing in the journal Nature, they claimed measurements of the sample’s reflective qualities were not conclusive proof of metallic hydrogen.
However Professor Silvera, who has been attempting to create metallic hydrogen for decades, said the absence of metallic hydrogen “suggests nothing, it suggests we couldn’t find it”.
“The sample is in the wreckage some place or it’s not meta-stable and it disappeared, it turned into a gas,” he said.
“If it was meta-stable and if it could withstand the shock of a catastrophic failure, it would still be in the gasket.”
He is due to speak about his research at an American Physical Society meeting the next few weeks.
And, by then, Professor Silvera hopes to have reproduced the same result that saw people queuing up in his laboratory for a look at the first piece of metallic hydrogen on Earth.
“We’ve got a pair of diamonds that we are now preparing for a run,” he said.
“There were a few Doubting Thomases, so we decided we should just reproduce it [use the same method].”
The controversy exists because Professor Silvera and fellow physicist Ranga Dias decided to keep the sample within the grip of the diamonds and study its properties, rather than risk removing it because of the danger that it was unstable and would be lost.
This meant it could only be viewed through the distorting prism of the diamonds.
And a sliver of non-metallic and transparent aluminia had been used to protect the diamonds from the hydrogen, which can cause them to become brittle and break under pressure.
So some experts suggested that the reflections used as evidence of metallic hydrogen could have actually come from the alumina, after it was changed into a metal by the extreme pressure.
Professor Silvera was adamant.
“Right now we think we have enough evidence that there should be no doubt it is metallic,” he said.
“I’m completely confident of the measurements we have made.”
He said recent research had showed that alumina would not have changed into a metal under the conditions it experienced in the experiment.
The search for metallic hydrogen is a competitive field with a number of teams around the world all striving for the same breakthrough.
“There have been a number of attempts to make metallic hydrogen. There have been several claims of metallic hydrogen,” Professor Silvera said.
“I’ve worked on this for many years. When I see a claim I examine it. I’ve written three or four papers when people make claims saying there’s evidence of metallic hydrogen.
“We would not have published a paper if we weren’t confident that it was metallic, especially after having refuted several other people who had claimed to have made metallic hydrogen.”
When the researchers' original paper in the journal Science was published, the congratulations had flooded in with even some from competitors.
They decided to open the lab for three hours so anyone could come in and look through the microscope trained on the historic sample.
“We said we would start it at 11am until 2pm. But someone came in at 7.30am and people were coming in all day long, just streaming in because it was something unique to see metallic hydrogen for the first time,” Professor Silvera said.
And he expressed confidence the results of their experiment would be repeated when they try again in the next few weeks and an almost incredibly shiny piece of metallic hydrogen will be once again on show.
“I’ll tell you what you will see with your eye because it will be reflecting like a mirror.”
This article has been edited to make clear non-metallic alumina, not metallic aluminium, was used to protect the diamonds from the hydrogen.
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