Author Topic: Metallic Hydrogen is real!  (Read 20458 times)

Online Welsh Dragon

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Re: Metallic Hydrogen is real!
« Reply #60 on: 01/28/2017 08:33 AM »
Yeah it is very different. To contrast, generally the only way I read any papers before publication in journals is if I'm an author on them. This is in neuroscience.
« Last Edit: 01/28/2017 08:33 AM by Welsh Dragon »

Offline Star One

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Re: Metallic Hydrogen is real!
« Reply #61 on: 01/28/2017 08:40 AM »
To make up for pushing the topic off thread, what are people's thoughts on if this is likely to be metastable, does the theory strongly suggest it should or is it more uncertain?

Offline Hobbes-22

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Re: Metallic Hydrogen is real!
« Reply #62 on: 01/28/2017 09:11 AM »
It was also hardly easy to manufacture considering the amount of preparation they had to make with the synthetic diamond vice alone. That pressure is ridiculous as well and how much energy did that use to create. Going to be as much about how you manufacture it as to if it's metastable.

IiRC they used a hand crank to compress the sample. The high pressure comes from concentrating a moderate force into a very small area.

Offline Katana

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Re: Metallic Hydrogen is real!
« Reply #63 on: 01/30/2017 04:05 PM »
With metallic hydrogen, the atoms need be broken out of the metallic matrix, but that probably takes a lot less energy.

Once that happens, aren't the individual atoms going to want to immediately revert to the H-H configuration (covalent bond) with commensurate release of energy?

No doubt, and, rereading the article and clicking through the links, the idea seems to be to rely on that energy alone, not bothering with the oxygen.

An Isp of 1700 s corresponds to an effective exhaust velocity of about 17 km/s.  For getting to LEO that's actually too high, if the objective is to minimize the amount of metallic hydrogen.  It might be optimal to add a cheap working fluid, ideally a monatomic one.  That would have the added advantage of keeping the temperature down.
The paper said that a monopropellant would have an Isp of 1700s and a temperature of around 7000K.  Hydrogen diluent to take the temperature down to 3500K-3800K would result in an Isp of 1030-1120s, and water diluent would have an Isp of 460-540s.

http://nrs.harvard.edu/urn-3:HUL.InstRepos:9569212

For diluted performance, compounds contain metastable polymers of Nitrogen instead of Hydrogen may work too.

Salts of N5+ stable to 50~60 degc and salts of cyclo N5- stable to 110~120degc.
https://en.m.wikipedia.org/wiki/Pentazenium
http://science.sciencemag.org/content/355/6323/374
The latter is reported on Science the same month of metal hydrogen.

Though these maybe still not stable enough for practical propellants, but less scifi.

Derivatives of tetrazole CH2N4 or azdide N3- are already suitable / used to improve propellant performance.

Offline allhumanbeings07

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Offline Stormbringer

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Re: Metallic Hydrogen is real!
« Reply #66 on: 02/23/2017 09:48 PM »
well it *was* real :)

Maybe.
« Last Edit: 02/23/2017 09:53 PM by Stormbringer »
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Offline KelvinZero

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Re: Metallic Hydrogen is real!
« Reply #67 on: 02/24/2017 08:23 AM »
...and it's gone

http://www.independent.co.uk/news/science/metallic-hydrogen-disappears-technology-revolutions-superconductor-faster-computers-super-efficient-a7593481.html
Glad I looked at the article. I had assumed it said disproved. The sample itself was lost.

Still could be real. It just has to be replicated, and (I guess this is redundant) repeatedly :-)

I hope it doesn't go the way of cold fusion with one guy just never giving it up and no one else ever able to find anything worthwhile. (that isn't a rigorously researched summary of cold fusion status, just my rough impression)

Offline IRobot

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Re: Metallic Hydrogen is real!
« Reply #68 on: 02/24/2017 09:54 AM »
This is good news, now they are forced to reproduce it earlier than expected.

Offline aquanaut99

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Re: Metallic Hydrogen is real!
« Reply #69 on: 02/24/2017 10:33 AM »
This is good news, now they are forced to reproduce it earlier than expected.

On the other hand, the fact that it immediately disappeared after the failure of the diamond, and the fact that the diamond was destroyed so completely, and in a fashion that had never been seen before (indicating massive force) makes me suspect that metallic hydrogen (assuming that sample really was metallic hydrogen) is probably not metastable. Which would mean no new wonder rocket fuel (or super-explosive, or superconductor or all the other fantastic stuff some people were already expecting...). Which is kind of a bummer...
« Last Edit: 02/24/2017 10:34 AM by aquanaut99 »

Offline Star One

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Re: Metallic Hydrogen is real!
« Reply #70 on: 02/24/2017 12:15 PM »
This is good news, now they are forced to reproduce it earlier than expected.

On the other hand, the fact that it immediately disappeared after the failure of the diamond, and the fact that the diamond was destroyed so completely, and in a fashion that had never been seen before (indicating massive force) makes me suspect that metallic hydrogen (assuming that sample really was metallic hydrogen) is probably not metastable. Which would mean no new wonder rocket fuel (or super-explosive, or superconductor or all the other fantastic stuff some people were already expecting...). Which is kind of a bummer...

As the article I linked to points out this is an assumption that cannot be made at this time.

Offline aquanaut99

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Re: Metallic Hydrogen is real!
« Reply #71 on: 02/24/2017 12:59 PM »
As the article I linked to points out this is an assumption that cannot be made at this time.

Everything I have heard (and note that I am absolutely no expert in this field) is that current experience in high-pressure physics argues against metallic hydrogen being metastable. In other words, it would be a huge surprise if it did turn out to be metastable (again, assuming it was actually created in the first place).

Apparently, the hype about metastable metallic hydrogen is based on a single theoretical paper from the early 1970s that was never experimentally proven.

I'm not saying that it's impossible that metallic hydrogen is metastable, just that it appears highly unlikely. And that therefore the hype that some articles have generated about the discovery is totally premature. Yes, it is possible (tho far from proven) that metallic hydrogen may have been created in a laboratory. Yes, that is a huge achievement in and of itself, mainly because it is something we've been trying to do for 80 years. But if it isn't metastable, then metallic hydrogen will only ever exist on this planet in minute quantities in a high-pressure lab. It will be interesting for researchers, but have no practical application whatsoever, and will never revolutionize spaceflight or give us room-temperature superconductors.

In fact, the actions of the researchers themselves indicate that they doubt that metallic hydrogen is metastable. Why else did they keep the sample in the high-pressure, ultra-cool state? After all, metastability being the key question, why wasn't the first experiment: take away the pressure and see what happens next?
« Last Edit: 02/24/2017 01:11 PM by aquanaut99 »

Offline IRobot

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Re: Metallic Hydrogen is real!
« Reply #72 on: 02/24/2017 01:14 PM »
This is good news, now they are forced to reproduce it earlier than expected.

On the other hand, the fact that it immediately disappeared after the failure of the diamond, and the fact that the diamond was destroyed so completely, and in a fashion that had never been seen before (indicating massive force) makes me suspect that metallic hydrogen (assuming that sample really was metallic hydrogen) is probably not metastable.
It could jus be among the debris... repeating the experiement over and over is the best way to proceed. If you can repeat it easily, you can do tests on the properties but also on the metastability.

Online Welsh Dragon

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Re: Metallic Hydrogen is real!
« Reply #73 on: 02/24/2017 02:05 PM »
Am I reading this right? They only did this once? What the hell were they doing announcing it if they've only done it once? What happened to reproducibility?

Offline RonM

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Re: Metallic Hydrogen is real!
« Reply #74 on: 02/24/2017 08:07 PM »
Am I reading this right? They only did this once? What the hell were they doing announcing it if they've only done it once? What happened to reproducibility?

People have been trying to create metallic hydrogen for decades. Like other groups before them, they announced ASAP to get the credit if it really worked. Reproducibility comes later. Personally, I agree with you, but it's a struggle to get grant money, so there's some showboating going on in research land.

Offline Stormbringer

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Re: Metallic Hydrogen is real!
« Reply #75 on: 02/25/2017 07:29 AM »
well according to the article they were already prepping to redo the experiment using the same protocols and similar equipment. For instance I think they state they already have another set of diamonds for their anvil...
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Offline ppnl

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Re: Metallic Hydrogen is real!
« Reply #76 on: 02/25/2017 08:27 AM »
Even if the stuff is real and metastable it is mostly only of theoretical value. It would probably cost billions to produce a gram of the stuff. Rocket fuel? Not likely.

Offline kch

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Re: Metallic Hydrogen is real!
« Reply #77 on: 02/25/2017 08:42 AM »
Even if the stuff is real and metastable it is mostly only of theoretical value. It would probably cost billions to produce a gram of the stuff. Rocket fuel? Not likely.

Might make a good (expensive) firecracker, though.  ;)

Offline IRobot

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Re: Metallic Hydrogen is real!
« Reply #78 on: 02/25/2017 10:58 AM »
Even if the stuff is real and metastable it is mostly only of theoretical value. It would probably cost billions to produce a gram of the stuff. Rocket fuel? Not likely.
You are confusing it with anti matter. I seriously doubt that it would cost billions to produce a gram. More likely thousands per gram and on an industrial scale maybe a few dollars per gram. Still maybe too expensive for rocket fuel.

Offline ppnl

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Re: Metallic Hydrogen is real!
« Reply #79 on: 02/27/2017 06:46 AM »


No, I think antimatter would cost orders of magnitude more.

The sample was a micron thick and less than the width of a human hair wide. How many specially polished and prepared diamonds will you need to use to produce a gram? How many of those diamonds are going to explode under the pressure?

And even if you produced a gram of the stuff how would you combine it into a larger object? It's unlikely you could melt a metastable substance without destroying it. And how ductile is it likely to be? Maybe less so than the diamonds you destroyed making it?

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