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Scientists Finally Turn Hydrogen Into a Metal, Ending a 80-Year Quest (arstechnica.com)
An anonymous reader quotes a report from Ars Technica: In 1935, scientists predicted that the simplest element, hydrogen, could also become metallic under pressure, and they calculated that it would take 25 GigaPascals to force this transition (each Gigapascal is about 10,000 atmospheres of pressure). That estimate, in the words of the people who have finally made metallic hydrogen, "was way off." It took until last year for us to reach pressures where the normal form of hydrogen started breaking down into individual atoms -- at 380 GigaPascals. Now, a pair of Harvard researchers has upped the pressure quite a bit more, and they have finally made hydrogen into a metal. All of these high-pressure studies rely on what are called diamond anvils. This hardware places small samples between two diamonds, which are hard enough to stand up to extreme pressure. As the diamonds are forced together, the pressure keeps going up. Current calculations suggested that metallic hydrogen might require just a slight boost in pressure from the earlier work, at pressures as low as 400 GigaPascals. But the researchers behind the new work, Ranga Dias and Isaac Silvera, discovered it needed quite a bit more than that. In making that discovery, they also came to a separate realization: normal diamonds weren't up to the task. "Diamond failure," they note, "is the principal limitation for achieving the required pressures to observe SMH," where SMH means "solid metallic hydrogen" rather than "shaking my head." The team came up with some ideas about what might be causing the diamonds to fail and corrected them. One possibility was surface defects, so they etched all diamonds down by five microns to eliminate these. Another problem may be that hydrogen under pressure could be forced into the diamond itself, weakening it. So they cooled the hydrogen to slow diffusion and added material to the anvil that absorbed free hydrogen. Shining lasers through the diamond seemed to trigger failures, so they switched to other sources of light to probe the sample. After loading the sample and cranking up the pressure (literally -- they turned a handcrank), they witnessed hydrogen's breakdown at high pressure, which converted it from a clear sample to a black substance, as had been described previously. But then, somewhere between 465 and 495 GigaPascals, the sample turned reflective, a key feature of metals The study has been published in the journal Science.
Fucking bad ass. This just strikes me as awesome. It's theoretical science made real. It's like a scientific profession of faith in reason made physical.
Questions abound!
Would the metal transition back to gas at one atmosphere? Would low temperatures retard the transition? Does it act as a superconductor? Is there any speculation on why the diamond destabilizes at a greater frequency under laser illumination? What likely metallurgical properties is it likely to exhibit? Is it likely we'll be able to take advantage of any of them at room temp / one atmosphere ?
Sometimes you really wish you had mod points so you could do something more useful than post how sad it is that a scientifically inaccurate post is getting modded up while a scientifically accurate corrective reply isn't.
For me, this is one of those times.
Also from the article was that it was observed to still have the properties they associated with being metallic at 83K.
83 degrees kelvin is a heck of a long way from room temperature.
Hence my inquiry about the practical benefits of this.
File under 'M' for 'Manic ranting'
In high school, I asked my grade 13 chemistry teacher why Hydrogen was on the left column of the periodic table where everything else was a metal. I was told because it had one electron in the outer shell, like everything else in that column.
The conversation went something like "But, if everything else in the column is a metal, doesn't that imply Hydrogen is a metal?" "No, it's a gas." "But hydrogen can be cooled to a liquid and it behaves like other liquefied metals (ie Mercury), couldn't it be cooled to the point where it is solid and will it behave like a metal?" "Go away."
In university, I asked the same question and was told that my reasoning was not unique and the idea was put forward many years before but that we'll probably never produce the necessary conditions on earth where Hydrogen will be a solid and we can see if it will be a metal.
Nice to see that we've done something that was thought to be, if not impossible, extremely difficult.
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Lets take a moment to remember we only thought this to occur in the centers of gas giants, in space, quite a bit far out there. We have just replicated this on this planet. Of all the posibilities for things to happen, this one is pretty rare. I feel proud to be a hairless monkey today.
I am a condensed matter physicist.
There are no practical applications of metallic hydrogen in the foreseeable future. There is an "always be selling" philosophy in science for the last few decades which is really unfortunate and has not been healthy for public trust of science. Many people have been sold on applications for metallic hydrogen that are not realistic.
Was this a waste of time? No. The fundamental theories of how metals are structured and how conductivity works say that hydrogen should be a great metal. The historic difficulty in creating metallic hydrogen may have meant that we were missing something important about how metals form, or missing something important about hydrogen (we discovered we were missing a lot of the necessary physics over the course of 80 years). The observation of metallic hydrogen now is an important verification of the level of completeness of our understanding of matter.
Spending 80 years to work something out is not so unusual in physics. Difficult projects take a few generations.
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Use it to power our cellphones?
Unlikely. But metallic hydrogen may have some very useful properties. It has been theorized to be a room temp superconductor. According to TFA, they haven't been able to test that yet.
Another factoid about SMH: It is believed to make up much of the mass of Jupiter, with Jovian SMH possibly making up the mass of a few dozen earths.
... and that, as we all know... is transparent aluminum.
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When I first saw your comment I thought you were making a joke. Then I realized there are people on this site who don't know what a metal is, and someone dumb enough to not know that might interpret the headline the way you did. Then I had a good laugh.
"Thank you for being my personal clown" -lots of people
... this endeavor was not simply a colossal waste of time?
Here's one interesting way to think about it. As per the article, scientists had used observations and measurements to predict that metallic hydrogen would require either 25GPa or (later) 380 - 400GPa of pressure. We now know that the known lower bound is somewhere around 465GPa. With this result, we can refine the models used in the original predictions and find out where they failed, and correct them.
With such corrections in hand, we may be able to make other predictions about hydrogen (or perhaps about other elements) with much more accuracy; and you just can't ever know where that might lead. It could lead to new battery technologies. It could lead to a better understanding of star formation. Maybe it revolutionizes material science.
That's the great thing about discovery -- it's often incremental, and you never know where a result might take you. At the very least, we can correct the models that once caused scientists to predict that 25GPa of pressure would turn hydrogen into a metal; where that can take us is an exciting unknown. Sometimes it's less about actually creating metallic hydrogen as much as it is what you learned along the way that becomes useful later.
(I'd think at the very least what has been learned about preventing diamond fragility at high pressures counts as a potentially immediately useful result -- although again, how someone might be able to use this in the future is an exciting question)
Yaz
If anything we step back and debate problems more than necessary. You can easily spend a career in physics identifying a single "difficulty" and putting together a plan for the next generation to tackle it.
I'm a third generation nanotechnologist. The guys 40+ years ago mapped out what they thought could be done (they were horribly wrong, but they were good guesses), and they developed the laboratory tools we needed just to look at the stuff (that didn't exist yet). This was hard, some of them won Nobel prizes for their work. The guys 20-30 years ago got some of the proof of concept work done by inventing new materials (in the end, not the right materials, but very close). This was also hard; some of them won Nobel prizes. I got to work on the very first applications with the right tools and the right materials. This was a lot easier; none of my generation is going to win anything. The people I trained get to do engineering and work on products. They can do in a day what took me a year, and what my mentor could just write about theoretically.
Still, we're very far away from the end of the road.
Several years ago I sent off a collection of wild ideas about "cold fusion" to a magazine, hoping for some feedback, and they published it as an actual article. Toward the end of the article was something about a possible way to test the hypothesis. Basically, if you could make some solid metallic hydrogen out of pure deuterium instead of ordinary hydrogen, some cold fusion might happen. It seems to me that the chances of someone being able to do such an experiment have now increased greatly....
Ehh, no. You are talking about the definition of "metal" in chemistry, which is a category of elements. The "transparent Aluminum" (or Aluminium if you prefer) as established in Star Trek, is not some sort of exotic state of the elemental Al, but a compound that can be created (using technology that is not futuristic). In fact, "transparent aluminum" doesn't even fit the alternate, more "loose", non-chemistry definition of "metal", as it is neither opaque, nor shiny. So, we are simply looking for a very strong transparent compound based on Aluminum. Sapphire and ruby might fit the bill if they can be made clear, but, as I learned from another post, there is something called Aluminium oxynitride and marketed as ALON, which makes pretty good transparent armor and generally seems to fit the description very well.
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At the moment it's not even known if metallic hydrogen can exist without such pressures. It's possible it will remain as a solid - which would be a solid with some really exotic and useful properties. Or, more disappointingly, it will more likely just sublime back into plain old hydrogen gas.