Last month, scientists from Harvard University reported the opening of the "Holy Grail" physics of solids. They managed to get hydrogen in the metal phase under laboratory conditions. Science has unsuccessfully tried to do this for more than 80 years. And, finally, success! Scientists not only were able to get the material, but also the first in history to find a way to keep it for preservation. Unfortunately, it was too early to rejoice. Scientists report that the sample was recently lost.
The incident occurred on February 11, when scientists were preparing a sample for transportation to the Argonne National Laboratory. The sample was stored at very low temperature and ultra-high pressure for further experiments. However, within the framework of one of the pressure tests with the help of a low-power laser installation, something happened: one of the two diamonds of the plant could not stand it and literally disintegrated into dust, buried under itself and the only sample of metallic hydrogen.
The head of the study, Professor Isaak Silvera, who has been studying metal hydrogen for more than 45 years, reports that scientists can not say with certainty which further destiny has befallen the only sample obtained.
"He's lost. He was either lost somewhere in the dust of the destroyed diamond and now is at normal pressure, or even returned to the gas state. We do not know for sure. "
"I've never seen anything like it. All surfaces of the installation covered a powder, similar to baking soda or something like that. I would not have believed that it was a diamond, "commented Professor Silver.
It is not necessary that the sample was destroyed, but since its size is only about 1.5 micrometers per 10 micrometers (about 1/5 of the diameter of an ordinary human hair), it is not possible to find it. But that's not all. The fact is that after the destruction of the diamond and the reduction of pressure in the installation, the sample could turn back into gas. According to the theory, it still should maintain a stable state, but if in fact it is not so, then this is even more sad news.
Despite very disappointing, the scientist said that now the team is working on creating stronger diamond grips and hopes to create another sample of metallic hydrogen in the near future.
"We're preparing a new experiment and see if it's possible to create the level of pressure that we reached for the first time and get another sample."
Why is metallic hydrogen so valuable? I think everyone knows that hydrogen is one of the most studied elements in the universe, and in its natural state it definitely does not have a metallic phase. He does not shine and does not conduct electricity. And yet, in 1935, physicists predicted that under certain pressure conditions hydrogen could acquire metallic properties. Since then, science has repeatedly tried to get at least one sample of metallic hydrogen in the laboratory. But all attempts were futile, because for possible success it was necessary to create conditions with incredibly strong pressure, which at that time the level of technology could not provide. And so, last October Silver and his team finally managed to do it. Using special diamond grips, scientists received a long-awaited pattern. With increasing pressure inside the system, the researchers saw with their own eyes how the transparent gas in the unit first darkened, and then it became shiny and acquired a metallic form.
The importance of the discovery lies not only in proving the possibility of the addition of a metallic form to hydrogen, but also in the fact that such a material can have potentially very useful properties - to become a superconductor capable of transmitting a charge without resistance. In addition, since it contains such an incredible amount of energy, it can also be considered as the "most powerful source for rocket fuel."
While waiting for the publication of his article in the scientific journal Science last month, scientists stored a sample of metallic hydrogen at ultra-low temperature and pressure, and also conducted several initial tests in the laboratory. One of the most important of them was the verification of its reflectivity - one of the characteristics confirming its metallicity.
With the help of a low-power laser installation, they measured the pressure at which metallic hydrogen acquired its shape. The results showed 495 GPa (about 4.9 million atmospheres), which is 4 million times greater than the atmospheric pressure level above sea level on Earth and about 20 times greater than the initial assumptions according to which it can be obtained.
However, many scientists did not have time to conduct many tests. The sample was lost before the article was published. For example, the researchers could not find out whether the resulting form of metallic hydrogen is liquid or solid. In addition, it has not been verified whether it is capable of conducting electricity, which is also one of the main characteristics for metals.
Therefore, it is not surprising that among the scientific community there were those who came out with a certain amount of skepticism as to whether or not metal hydrogen was created at all.
"I do not think that this published article will be convincing for everyone," said physicist Paul Luber of the French Atomic Energy Commission in Bruyères-le-Châtel, who did not participate in the study, to Nature.
To conduct further tests, Silver and his team planned to use a synchrotron in the Argonne National Laboratory in the United States. However, before sending the sample, they decided to use a low-power red laser to check the pressure created inside the storage system. But this time the energy created by the laser virtually instantaneously destroyed the system. One of the diamonds of the installation literally crumbled to dust.
"Similar things have already happened to other teams, but we thought that everything would be in order with our system. We have repeatedly experienced it in the past, but, apparently, something has changed in it since that time. Perhaps in the diamond itself a defect has arisen, perhaps the reason is the diffusion of hydrogen. We just do not know. And hardly we will know. "
Silver is convinced that his team will be able to create new samples. And if not in the framework of the following experiments, then at least in the near future. Scientists very much hope to repeat the process, so that the evil tongues do not have this time arguments.
"The disappearance of the sample does not say anything. Anyone who works with high-pressure conditions knows very well that such incidents can really happen from time to time. I'm glad that we managed to at least test the reflectivity of the sample and this data is accurate, "- says Silver.
"What happened can not be called a step back. It's just a shame that we could not carry out more measurements of this sample. In science there will always be a bunch of skeptics on this or that issue, but my advice to such people is always the same: try to conduct the experiment yourself. We have already shown what kind of pressure we created to produce metallic hydrogen in the laboratory. Therefore, anyone who wants and has the same opportunity can try to do it themselves. This is what I call the scientific method. And it's much better than just complaining about our results, "the scientist added.
In the following experiments, the team will try to use different types of synthetic diamonds, which, hopefully, will be more stable. In addition, it is planned to use a more powerful cooling system. Bitter experience has shown that planned inspections and experiments in such cases are better done without delay.
"It is possible that with prolonged storage, such samples become less stable. Therefore, the next time, when using high pressure we will get a new sample, we will try to conduct all important measurements as soon as possible, "Silvera said.
The article is based on materials .
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