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New claim at metallic hydrogen discovery


Dilir

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Unfortunately it is pretty clear that metallic hydrogen isn't metastable, and extremely clear that compressing it to 480GPa (and somewhat more) does not leave metallic hydrogen when the pressure is removed.  It doesn't really qualify as a "science fiction rocket fuel" (for KSP2) as we know it almost certainly doesn't work that way.

Edited by wumpus
Fixed. Here's to redundant writing so people don't think you really meant that stupid error. Thanks redundancy!
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25 minutes ago, wumpus said:

Unfortunately it is pretty clear that metallic hydrogen is metastable, and extremely clear that compressing it to 480GPa (and somewhat more) does not leave metallic hydrogen when the pressure is removed.  It doesn't really qualify as a "science fiction rocket fuel" (for KSP2) as we know it almost certainly doesn't work that way.

I assume you meant *isn't metastable, right?

 

Also, given that this is, what, the third or fourth completely unconfirmed discovery, I'm not sure if it's really "pretty clear." 

 

But yeah, I'm not getting my hopes up. Even if it is metastable, mass production would be... uh, difficult.

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7 hours ago, ThatGuyWithALongUsername said:

Cool, wonder how long it's gonna be until this thread turns into another argument over KSP2

I think we need to discuss the elephant in the room first.

on_orbit_by_william_black-d794jfo.jpg?to

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3 hours ago, DDE said:

I think we need to discuss the elephant in the room first.

[imagine a picture of old boom-boom here]

Kerbal politics, if there are any, doesn't seem to get in the way of your Kerbal Space Program (although it might not be all that great for your popularity.  Especially if one crashes down on Kerbal).  So it should be a viable option.

We also don't know if the unobtanium that makes up Kerbal creates a magnetosphere to drag back all the radioactive exhaust back to the biosphere.  Even so, I suspect KSP2 will allow multiple launch sites, and allow arctic launches (expect to have to build the base with kredits/roots).

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15 hours ago, wumpus said:

Kerbal politics, if there are any, doesn't seem to get in the way of your Kerbal Space Program (although it might not be all that great for your popularity.  Especially if one crashes down on Kerbal).  So it should be a viable option.

We also don't know if the unobtanium that makes up Kerbal creates a magnetosphere to drag back all the radioactive exhaust back to the biosphere.  Even so, I suspect KSP2 will allow multiple launch sites, and allow arctic launches (expect to have to build the base with kredits/roots).

Kerbals probably don't have the issue with nuclear bombs we have. Don't looks like it wars. 

However an orion engine is very heavy so its best suited for large ships. They are also not very suitable for landing especially close to bases :)
Lots of other engines are radioactive including nerva and the fusion engines or require heavy reactors or huge solar panels again not very suitable for an lander. 
Yes you can use standard fuel and oxidizer but that require an larger lander who require an larger mothership. 

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On 1/30/2020 at 12:54 PM, wumpus said:

Unfortunately it is pretty clear that metallic hydrogen isn't metastable

Definitely not at anything like 1atm, but there might be a pressure range at which it is metastable that is attainable in fuel tanks. If it also turns out to be a superfluid or supersolid, we might be able to work with it as a fuel even then. Yes, lots of "if" statements there. Just saying we can't definitively discount it, but it's definitely in the "don't hold your breath" category.

Could still be useful for things, even if we can only maintain necessary pressure on microscopic levels.

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20 hours ago, kerbiloid said:

So, we can just make a foam of nanoblackholes and store the metallic hydrogen as superdense accretion nanodiscs around them.

LOL, kind of taking the chemical rockets versus orion but buffing everything some orders of magnitudes. 
An black hole space ship is that you use to move stuff like earth. Its more removed from an atomic hydrogen engine than an trireme is from an battleship. 

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2 hours ago, magnemoe said:

An black hole space ship is that you use to move stuff like earth. Its more removed from an atomic hydrogen engine than an trireme is from an battleship. 

Probably, but could the trireme work on the battleship fuel?
Maybe the metallic hydrogen is a fuel for enough large ships?

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On 2/2/2020 at 11:24 PM, K^2 said:

Definitely not at anything like 1atm, but there might be a pressure range at which it is metastable that is attainable in fuel tanks. 

I addressed this paper months ago (when it was in pre-print):

It wasn't even metastable at 415 GPa. It appeared to go metallic at 427 GPa, but when they dropped it to 410 and 415 GPa, it was no longer metallic. There were no intermediate datapoints between reaching 427 GPa, and when they lowered pressure to those lower numbers (the "410 and 415" I give is because they had two figures showing experimental results showing it reverted). So it seems it reverted somewhere between 427 GPa and 415 GPa... If I had to wager, I'd say it was probably non-metallic again at 425 GPa.

They literally say the metallic state transforms back to the C2/c-24 phase with almost no hysteresis, so I think any dreams of using it as rocket fuel are dead. 

Now the only hope is that if you compress it even more, it will form a different state, that is metastable. After all, you can compress water into multiple forms of solid/there are multiple forms of "ice" depending on pressure. Likewise solid carbon can be compressed into solid diamond... I am aware of no case where something that was not stable was made stable by compressing it further... so I still think the dream is dead.

 

 

 

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Of course it's dead. This is why I keep saying that (and telling KSP2 devs to knock it off). The results are pretty unambiguous, metallic hydrogen is dead, as far as rocketry is concerned.

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2 hours ago, Dragon01 said:

Of course it's dead. This is why I keep saying that (and telling KSP2 devs to knock it off). The results are pretty unambiguous, metallic hydrogen is dead, as far as rocketry is concerned.

Physic is a bit different in the KSP universe, planets and stars tend to be more dense somehow, items are also heavier than on earth. light speed is much much higher and so on. 

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Not really. Yeah, the world in Newtonian, but relativity doesn't come into play at Kerbals' tech level, anyway (except for the missing signal delay). As for densities, they're weird, but they don't show physics the middle finger. Items, in particular, aren't heavier than on Earth, just not as well engineered because they don't need to be. KSP universe is ridiculously contrived, but not impossible.

Metallic hydrogen being useful as fuel, on the other hand, is impossible. It just doesn't work. In an educational game (Squad's language, I would be surprised if ST didn't inherit it), it's inexcusable.

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4 hours ago, Dragon01 said:

Not really. Yeah, the world in Newtonian, but relativity doesn't come into play at Kerbals' tech level, anyway (except for the missing signal delay). As for densities, they're weird, but they don't show physics the middle finger. Items, in particular, aren't heavier than on Earth, just not as well engineered because they don't need to be. KSP universe is ridiculously contrived, but not impossible.

Metallic hydrogen being useful as fuel, on the other hand, is impossible. It just doesn't work. In an educational game (Squad's language, I would be surprised if ST didn't inherit it), it's inexcusable.

Isn't planetary density higher than uranium?  As in, you'd need some "island of stability" in the far elements to build Kerbol?

Metallic hydrogen would also be exceptionally hard to work into the game.  Unless the metallic hydrogen was prohibitively expensive, it would just be a matter of gaining the science and infrastructure to obtain metallic hydrogen and then more or less "winning" the game (although to a certain extent so do spaceplanes and in situ fuel production).  But the window has closed (if it was ever really open, I doubt it) to be honestly used as a "science fiction" element.

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Check what KSP2 devs had made of it. According to the trailer, it's one step up from NTRs (because advanced NTR designs are, apparently, not a thing). They pretty much ignore all the problems it would have even if it did work.

Kerbin's density might be on the high side, but it's not forbidden by physics. Yes, you might need a lump of neutronium at the core, but it's not impossible, just absurdly contrived. Once again, this is not the same as implementing a magic drive.

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15 hours ago, KerikBalm said:

It wasn't even metastable at 415 GPa.

That's unfortunate. I do wonder if there are supersolid states at low enough temperature that might be more interesting, but given how high the specific energy is at that pressure, I doubt that any quantum effects will make a practical difference.

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1 hour ago, Dragon01 said:

Not really. Yeah, the world in Newtonian, but relativity doesn't come into play at Kerbals' tech level, anyway (except for the missing signal delay). As for densities, they're weird, but they don't show physics the middle finger. Items, in particular, aren't heavier than on Earth, just not as well engineered because they don't need to be. KSP universe is ridiculously contrived, but not impossible.

Metallic hydrogen being useful as fuel, on the other hand, is impossible. It just doesn't work. In an educational game (Squad's language, I would be surprised if ST didn't inherit it), it's inexcusable.

Yes, however KSP 2 dev cycle started then metallic hydrogen was very hyped. Kind of like Niven's coldest place was kind of embarrassing  for him  as story was an manned mission to an tidal locked Mercury and the dark side was extremely cold because it was lots of focus on Mercury, assume first flyby. How also showed that Mercury was not tidal locked. 
Yes they could add other engines like vasmir or various fission and fusion rockets. However it give you higher isp deep space engine for large ships in an tech tree. We know we get Orion and the big one leaving the Jool orbit construction yard. 
All went WOW and then, asparagus stage it :) 

However the elephant in the room is first stage reuse, its not practical in KSP1 without mods, in KSP2 it require multiplayer kind of like the 1950 concepts with manned first stage. 
SpaceX has it an standard at this time. People will still be playing KSP 2 long after starship is operational and the mix of fusion engines and discarding boosters will feel weird to new players. 
 

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Well, it's a magic drive that makes the game fun, which is what I cares about the most.(I play ksp for it's accurate orbital mechanics, and the performance of metallic hydrogen engines probably won't be too absurd, maybe close to nukes but a bit better.)

Edited by Space Nerd
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8 hours ago, magnemoe said:

However the elephant in the room is first stage reuse, its not practical in KSP1 without mods, in KSP2 it require multiplayer kind of like the 1950 concepts with manned first stage. 

You don't know that, and it might not be true. If KSP2 provides some sort of autopilot, and doesn't unload craft under its control (both reasonable additions), automatic reuse might well be possible. Whether it'll be practical depends on the parts we are given.

Oh, Ninven's story still kind of works. Mercury isn't tidally locked, but it's close enough for purposes of someone living on it. He wasn't banking on highly uncertain science, but actual observations that were revealed to be slightly inaccurate.

8 hours ago, Space Nerd said:

Well, it's a magic drive that makes the game fun, which is what I cares about the most.(I play ksp for it's accurate orbital mechanics, and the performance of metallic hydrogen engines probably won't be too absurd, maybe close to nukes but a bit better.)

That would be fine if the game didn't bill itself as educational. It's vital that an educational game does not spread outright falsehoods, because they'll be taken as truth and spread further. Honestly, there are so many cool engine concept proposals which might actually work, that using a single one that was proven not to is stupid. Any other attitude towards falsehood than "no, just no" only makes the problem worse.

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Ok i have a question. This might be pretty stupid, and i freely admit i have very limited knowlege about this stuff. So feel free to roll your eyes or something :) .

Iron changes its behaviour pretty massively depending on stuff you mix in. Add some carbon -> steel. Add some trace amounts of other stuff -> steel with vastly different brittelnes, melting points and so on.

Could this be possible for metal hydrogen ? Maybe you could make it metastable to a degree by adding the right mix of "pollution" ?

Edited by hms_warrior
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11 minutes ago, hms_warrior said:

Could this be possible for metal hydrogen ? Maybe you could make it metastable to a degree by adding the right mix of "pollution" ?

If you check the other thread, I think it was covered. So far adding other metals has decreased the pressure required to form it (also decreases energy stored, an decreases Isp), but it hasn't made it metastable

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