Metallic hydrogen, once theory, becomes reality

January 26, 2017
Image of diamond anvils compressing molecular hydrogen. At higher pressure the sample converts to atomic hydrogen, as shown on the right. Credit: R. Dias and I.F. Silvera

Nearly a century after it was theorized, Harvard scientists have succeeded in creating the rarest - and potentially one of the most valuable - materials on the planet.

The material - atomic - was created by Thomas D. Cabot Professor of the Natural Sciences Isaac Silvera and post-doctoral fellow Ranga Dias. In addition to helping scientists answer fundamental questions about the nature of matter, the material is theorized to have a wide range of applications, including as a . The creation of the rare material is described in a January 26 paper published in Science.

"This is the holy grail of high-pressure physics," Silvera said. "It's the first-ever sample of metallic hydrogen on Earth, so when you're looking at it, you're looking at something that's never existed before."

To create it, Silvera and Dias squeezed a tiny hydrogen sample at 495 gigapascal, or more than 71.7 million pounds-per-square inch - greater than the pressure at the center of the Earth. At those extreme pressures, Silvera explained, solid molecular hydrogen -which consists of molecules on the lattice sites of the solid - breaks down, and the tightly bound molecules dissociate to transforms into , which is a metal.

While the work offers an important new window into understanding the general properties of hydrogen, it also offers tantalizing hints at potentially revolutionary new .

"One prediction that's very important is metallic hydrogen is predicted to be meta-stable," Silvera said. "That means if you take the pressure off, it will stay metallic, similar to the way diamonds form from graphite under intense heat and pressure, but remains a diamond when that pressure and heat is removed."

Understanding whether the material is stable is important, Silvera said, because predictions suggest metallic hydrogen could act as a superconductor at room temperatures.

"That would be revolutionary," he said. "As much as 15 percent of energy is lost to dissipation during transmission, so if you could make wires from this material and use them in the electrical grid, it could change that story."

Among the holy grails of physics, a room temperature superconductor, Dias said, could radically change our transportation system, making magnetic levitation of high-speed trains possible, as well as making electric cars more efficient and improving the performance of many electronic devices.

The material could also provide major improvements in energy production and storage - because superconductors have zero resistance energy could be stored by maintaining currents in superconducting coils, and then be used when needed.

Photos of compressed hydrogen transitioning with increasing pressure from transparent molecular to black molecular to atomic metallic hydrogen. The sketches below show a molecular solid being compressed and then dissociated to atomic hydrogen. Credit: R. Dias and I.F. Silvera

Though it has the potential to transform life on Earth, metallic hydrogen could also play a key role in helping humans explore the far reaches of space, as the most powerful rocket propellant yet discovered.

"It takes a tremendous amount of energy to make metallic hydrogen," Silvera explained. "And if you convert it back to molecular hydrogen, all that energy is released, so it would make it the most powerful rocket propellant known to man, and could revolutionize rocketry."

The most powerful fuels in use today are characterized by a "specific impulse" - a measure, in seconds, of how fast a propellant is fired from the back of a rocket - of 450 seconds. The specific impulse for metallic hydrogen, by comparison, is theorized to be 1,700 seconds.

"That would easily allow you to explore the outer planets," Silvera said. "We would be able to put rockets into orbit with only one stage, versus two, and could send up larger payloads, so it could be very important."

To create the new material, Silvera and Dias turned to one of the hardest materials on Earth - diamond.

But rather than natural diamond, Silvera and Dias used two small pieces of carefully polished synthetic diamond which were then treated to make them even tougher and then mounted opposite each other in a device known as a .

"Diamonds are polished with diamond powder, and that can gouge out carbon from the surface," Silvera said. "When we looked at the diamond using atomic force microscopy, we found defects, which could cause it to weaken and break."

The solution, he said, was to use a reactive ion etching process to shave a tiny layer - just five microns thick, or about one-tenth of a human hair - from the diamond's surface. The diamonds were then coated with a thin layer of alumina to prevent the hydrogen from diffusing into their crystal structure and embrittling them.

After more than four decades of work on metallic hydrogen, and nearly a century after it was first theorized, seeing the material for the first time, Silvera said, was thrilling.

"It was really exciting," he said. "Ranga was running the experiment, and we thought we might get there, but when he called me and said, 'The sample is shining,' I went running down there, and it was metallic hydrogen.

"I immediately said we have to make the measurements to confirm it, so we rearranged the lab...and that's what we did," he said. "It's a tremendous achievement, and even if it only exists in this diamond anvil cell at high pressure, it's a very fundamental and transformative discovery."

Explore further: Spacecraft Juno nears planet orbit, but Harvard team may already have predicted part of what it will find

More information: "Observation of the Wigner-Huntington transition to metallic hydrogen," Science, science.sciencemag.org/lookup/ … 1126/science.aal1579

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37 comments

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KBK
2 / 5 (3) Jan 26, 2017
Lets try igniting it, like splitting that there beer atom. (Young Einstein)
Sonhouse
4 / 5 (4) Jan 26, 2017
So, the question now is, does it remain metallic if the pressure is removed.

If it reverts, don't see how this development would be anything but a lab curiosity. But it is great work to even get as far as they did!

NoStrings
not rated yet Jan 26, 2017
This would be amazing. Room temperature superconductor - best thing ever.
One small thing - if the hydrogen wires start on fire, it will be hot. Small thing. But rocket fuel pellets are great - almost as good as nuclear thermal propulsion.
TheGhostofOtto1923
3.7 / 5 (3) Jan 26, 2017
"It takes a tremendous amount of energy to make metallic hydrogen," Silvera explained. "And if you convert it back to molecular hydrogen, all that energy is released, so it would make it the most powerful rocket propellant known to man, and could revolutionize rocketry."

-Except for fission, fusion, and antimatter.

"Project Orion was a study of a spacecraft intended to be directly propelled by a series of explosions of atomic bombs behind the craft (nuclear pulse propulsion). Early versions of this vehicle were proposed to take off from the ground with significant associated nuclear fallout; later versions were presented for use only in space."

-But I didnt know about metastable and room temp superconductor. I wonder what else you could squeeze and store energy with?

I wonder if this could trigger a pure fusion bomb?
Pooua
1 / 5 (2) Jan 26, 2017
Diamonds are not stable at standard pressure and temperature. It might take millions of years, but diamonds left at room temperature and pressure eventually will revert to other forms of carbon. If metallic hydrogen is metastable under ordinary conditions, I wonder how long it would remain stable? What about at elevated temperatures or under strain?
philstacy9
not rated yet Jan 26, 2017
" Recomobination of hydrogen from the metallic state would release 216 megajoules per kilogram; TNT only releases 4.2 megajoules per kilo"
http://up-ship.co...?p=33494
TheGhostofOtto1923
1 / 5 (3) Jan 26, 2017
" Recomobination of hydrogen from the metallic state would release 216 megajoules per kilogram; TNT only releases 4.2 megajoules per kilo"
http://up-ship.co...?p=33494
" The hydrino reaction releases 50 MJ/mole"
" How many moles Hydrogen in 1 grams? The answer is 0.992122546977"

- I think thats (lots) more. But then does the universe really need more dark matter?
Whydening Gyre
5 / 5 (2) Jan 27, 2017
Diamonds are not stable at standard pressure and temperature. It might take millions of years, but diamonds left at room temperature and pressure eventually will revert to other forms of carbon. If metallic hydrogen is metastable under ordinary conditions, I wonder how long it would remain stable? What about at elevated temperatures or under strain?

FTA;
"One prediction that's very important is metallic hydrogen is predicted to be meta-stable," Silvera said. "That means if you take the pressure off, it will stay metallic, similar to the way diamonds form from graphite under intense heat and pressure, but remains a diamond when that pressure and heat is removed."

However, it is not stated what happened with their new creation once they removed the pressure...
antialias_physorg
5 / 5 (1) Jan 27, 2017
if the hydrogen wires start on fire, it will be hot.

" Recomobination of hydrogen from the metallic state would release 216 megajoules per kilogram; TNT only releases 4.2 megajoules per kilo"

But since they're superconducting you need very little of it. Wires can be extremely thin because superconduction materials can convey currents on the order of 100k amps per square centimeter.
jeshua
5 / 5 (1) Jan 27, 2017
So can the same technique be used with different atoms? For instance, could metallic oxygen, or metallic helium be created, with I suspect novel properties? Perhaps even mixed atoms?
antialias_physorg
5 / 5 (2) Jan 27, 2017
Metallic helium is theoretically possible. At low temperatures the pressure required is thought to be about an 3 orders of magnitude above what is reported here for hydrogen.
According to this:
http://www.pnas.o....extract
There might be some metallic helium (in a degenerate fluid-metallic state mixed with hydrogen) at Jupiters core.

Metallic oxygen has already been produced
https://en.wikipe...c_oxygen

Neither metallic helium nor metallic oxygen are metastable at ambient conditons as far as I'm aware.
sciencex99
not rated yet Jan 27, 2017
Room tempuratore Superconductor material that is also a rocket fuel!!!!
that sounds like an explosive combination... throw in a few spark plugs...
and you and destroy the entire power grid with the same force as 1000000 TNT sticks of dynomite....

Might work on mars or outer space where there is no oxygen however....
in that case you don't need room temp. superconductor because its cold as hell...

Something about sparkyelectricity and rocket fuel being used in the same sentence....
sciencex99
not rated yet Jan 27, 2017
metallic hydrogen....I'm sure its probably useful for starting nuclear reactions.....
if we hear about a lab somewhere going thermonulear for no reason we will know why...;-)
Sonhouse
5 / 5 (2) Jan 27, 2017
All this talk about super fuels when metallic converts to gas but we don't even know if the stuff stays metallic when the pressure lets up. Anyone know about that? Seems a fundamental question to ask. Till then, stop the hype about super fuels.

Suppose it is stable when pressure is gone, how do you go about making more than a micron thick layer of the stuff? You have a charge of H2 compressed like a combustion engine, bang after bang, 1 micron, 1 micron, 1 micron? Exactly how would one go about going from this lab trick to an industrial process even if the stuff is stable with no pressure?

Did you get that part where they compressed it to near 500 gigapascal, over 70 MILLION PSI? Just exactly how does one go about that on an industrial scale?
TheGhostofOtto1923
1 / 5 (2) Jan 27, 2017
As far as power production with H2 goes, here is an interesting development

"Airbus Continues Engagement in Cold Fusion, Files Patents for 'Fusion Reactor' and 'Fusing Ultra-Dense Hydrogen'"
However, it is not stated what happened with their new creation once they removed the pressure...
Well what happens to diamond when you remove the pressure? Your quote says its similar to that.
Did you get that part where they compressed it to near 500 gigapascal, over 70 MILLION PSI? Just exactly how does one go about that on an industrial scale?
Your question implies impossibility. What makes YOU think its impossible?

Artificial diamonds were once thought impossible before they found an easy way to manufacture them.
Whydening Gyre
5 / 5 (2) Jan 27, 2017
However, it is not stated what happened with their new creation once they removed the pressure...

Well what happens to diamond when you remove the pressure? Your quote says its similar to that.


No, the Article says it is PREDICTED to be stable. What happened to their sample when they removed the pressure retraint?
etherair
1 / 5 (1) Jan 27, 2017
So ten years ago when I read about metallic hydrogen being produced in diamond cell anvils it was 'fake news' as they only now did it?
Or is this 'fake news' as the process has been used for ten years but only now has pictures?
I was studying quantum entanglement five years before it was 'discovered' also. Quite a bit of controversy in those days, perhaps the 'discovery' was when they took a vote to agree on a press release.
Dissembling science to non science audiences by non science reporters is a step above political science in that it is not deliberately misleading, only incomplete.
Sonhouse
5 / 5 (2) Jan 27, 2017
As far as power production with H2 goes, here is an interesting development

"Airbus Continues Engagement in Cold Fusion, Files Patents for 'Fusion Reactor' and 'Fusing Ultra-Dense Hydrogen'"
However, it is not stated what happened with their new creation once they removed the pressure...
Well what happens to diamond when you remove the pressure? Your quote says its similar to that.
Did you get that part where they compressed it to near 500 gigapascal, over 70 MILLION PSI? Just exactly how does one go about that on an industrial scale?
Your question implies impossibility. What makes YOU think its impossible?

Artificial diamonds were once thought impossible before they found an easy way to manufacture them.

I wasn't implying impossibility, I was asking if anyone had any idea just how to get that much pressure on an industrial scale. It's one thing to make metallic H2 on a diamond anvil a millimeter square, quite another making thousands of tons of it.
neotesla
5 / 5 (3) Jan 27, 2017
Merrit
not rated yet Jan 27, 2017
Sonhouse has a point. It will be way to costly to make to be used commercially. Also, near impossible to make large samples. They would have to make many small samples in parallel and you end up with something like sand. If you can melt it and reform it this isn't an issue, but that process could destabilize it back to gas.
TheGhostofOtto1923
1 / 5 (2) Jan 27, 2017
No, the Article says it is PREDICTED to be stable. What happened to their sample when they removed the pressure retraint?
Why dont you do a little research beyond this pr news release and find out?

How do scientists answer questions such as these? They do experiments. When they say 'PREDICTED' it means they havent tried it yet. Why are you asking a question without an answer at the present??
It will be way to costly to make to be used commercially
Why? Because it sounds costly? How do you know it would be costly?

Like I say, Chemical vapor deposition doesnt take pressure and it is used to make diamonds.

One way to produce pressures in that range is by detonating certain explosives. This is another way diamonds are made.
Whydening Gyre
5 / 5 (3) Jan 27, 2017
Kinda snippy there, GoO...

From ARXIV;
"As of the writing of this article we are maintaining the first sample of the first element in
the form of solid metallic hydrogen at liquid nitrogen temperature in a cryostat. This valuable
sample may survive warming to room temperature and the DAC could be extracted from the
cryostat for greatly enhanced observation and further study. Another possibility is to cool to
liquid helium temperatures and slowly release the load to see if SMH is metastable. An
important future measurement is to study this metal for high temperature superconductivity."

Seems like they could have just tried it and then just made another sample if it didn't...
Whydening Gyre
5 / 5 (1) Jan 27, 2017
Sonhouse has a point. It will be way to costly to make to be used commercially. Also, near impossible to make large samples. They would have to make many small samples in parallel and you end up with something like sand. If you can melt it and reform it this isn't an issue, but that process could destabilize it back to gas.

"Something like sand" could be worked with...
ski137
5 / 5 (1) Jan 27, 2017
If the stuff is metastable and can occur in nature could there be deposits of it within asteroids or metallic comets?
Da Schneib
5 / 5 (1) Jan 28, 2017
If the stuff is metastable and can occur in nature could there be deposits of it within asteroids or metallic comets?
As a matter of fact they think it makes up a fair part of the core of Jupiter, but there would have had to be another gas giant in the Solar System that broke up for there to be any asteroids or comets that had it in them. And we know that didn't happen.
Da Schneib
5 / 5 (3) Jan 28, 2017
I wasn't implying impossibility, I was asking if anyone had any idea just how to get that much pressure on an industrial scale. It's one thing to make metallic H2 on a diamond anvil a millimeter square, quite another making thousands of tons of it.
Finding out if you can do it at all is science. Figuring out how to do it as an industrial process is engineering. If it's really that big a deal, we'll figure it out.
Da Schneib
5 / 5 (1) Jan 28, 2017
I'd be interested in the details of the design of the diamond anvil cell that allowed it to exert almost twice what previous efforts could accomplish. It seems to me this is the real advance here.

Meanwhile, seems like these folks are as jealous as a bunch of beauty queens. Rather unseemly.
TheGhostofOtto1923
1 / 5 (3) Jan 28, 2017
I'd be interested in the details of the design of the diamond anvil cell that allowed it to exert almost twice what previous efforts could accomplish. It seems to me this is the real advance here
Id be interested to know whether you were curious enough to read the sciencemag paper referenced at the bottom of the article?
SiaoX
not rated yet Jan 28, 2017
Physicists doubt bold report of metallic hydrogen. According to this picture the compressed hydrogen could change into transparent electride instead. Without conductivity measurements the transparent sample remains indistinguishable from reflecting one. Wouldn't be possible to shine at sample with laser of different color from above and from bellow at least?
swordsman
not rated yet Jan 28, 2017
"Metallic"?? If it is metallic, then it will conduct electrons. Guide an electron stream through it.
BrillouinEnergy
not rated yet Jan 28, 2017
If they are saying "...even if it only exists in this diamond anvil cell at high pressure, it's a very fundamental and transformative discovery."
why bother printing things like
"
The most powerful fuels in use today are characterized by a "specific impulse" - a measure, in seconds, of how fast a propellant is fired from the back of a rocket - of 450 seconds. The specific impulse for metallic hydrogen, by comparison, is theorized to be 1,700 seconds.

"That would easily allow you to explore the outer planets," Silvera said. "We would be able to put rockets into orbit with only one stage, versus two, and could send up larger payloads, so it could be very important."
"
Or have they not reduced the pressure on the anvil yet?
TheGhostofOtto1923
1 / 5 (3) Jan 28, 2017
"Metallic"?? If it is metallic, then it will conduct electrons. Guide an electron stream through it
Try looking things up before offering opinions. If physicists are calling something metallic then obviously youre missing something yes?

Or have they not reduced the pressure on the anvil yet?
Why dont you read the paper instead of asking people to do it for you?
Da Schneib
not rated yet Jan 28, 2017
Or have they not reduced the pressure on the anvil yet?
They're keeping the sample very cold and under pressure:
As of the writing of this article we are maintaining the first sample of the first element in the form of solid metallic hydrogen at liquid nitrogen temperature in a cryostat.

This valuable sample may survive warming to room temperature and the DAC could be extracted from the cryostat for greatly enhanced observation and further study.

Another possibility is to cool to liquid helium temperatures and slowly release the load to see if SMH is metastable.


You should read the arXiv version their paper, if you don't have access to Science: https://arxiv.org...1634.pdf
SiaoX
2.3 / 5 (3) Jan 28, 2017
The shininess may be something else entirely – like aluminium oxide, which is known to coat the diamonds that sit in the anvil and also becomes shiny under high pressure. Scientists have also cast doubt on the amount of pressure, that the paper claims to have pushed onto the hydrogen: the researchers shouldn't extrapolate the pressure by counting winding on the screws: they should measure it inside the diamond anvil.
Da Schneib
1 / 5 (1) Jan 28, 2017
One assumes you are one of these individuals engaged in unseemly whining.

The reasons the pressure cannot be directly measured are given in the paper, which you apparently still have not read.

Are you actually claiming that you can turn the crank on the anvil and not increase the pressure? Really? Really?

What exactly is turning the sapphire from transparent (as it must be for the results at 290 GPa, documented in the paper, to be seen) to reflective? Do you have any experimental data that shows that the sapphire becomes reflective under these circumstances? Or even any theoretical evidence to support this contention?

Shameful.
nikola_milovic_378
1 / 5 (1) Feb 04, 2017
From this "evidence" that hydrogen can be "camouflaged" in a metallic state, we see that science is not familiar with the processes of formation and dissolution of matter. If you had know way of formation of matter, we must know that each chemical element is formed of a set of hydrogen atoms, under different thermodynamic processes taking place with two special effects such as magnetism and gravity. The current scientists think they can imitate their experiments the processes taking place in the formation of matter, and these conditions (magnetic field strength, temperature, pressure, gravity, and the very foundation from which matter is formed (ether), the mysterious human power. In this formation matter, we can not do anything new well, only we can "play" with what nature has left. But we can spoil everything, as do those in the Hadron Collider. what does "metallic" hydrogen? If you compress a bunch of atoms hydrogen, what happens?
nikola_milovic_378
1 / 5 (1) Feb 04, 2017
Atom deformed and electrons escaping where they can "hide" and where is this place? Out of that crowd I can not run, because of the powerful "siege", and remains them to "dig" into protons. what do you get? Neutrons. but this is not a niche atom because electrons do not exist. this is the quark-gluon plasma, or very "loose" because he pretended ignorant and as soon as the pressure returns to all in some other form. and if you remain such a situation, it is not hydrogen.

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