7 ms·
Tangentially, the metallic hydrogen mentioned is one of the craziest chemical substances to possibly-exist [0]. Besides likely being a room-temperature superco
by throwaway_yy2Di 12y ago
Tangentially, the metallic hydrogen mentioned is one of the craziest chemical substances to possibly-exist [0].
Besides likely being a room-temperature superconductor (at ridiculous pressures, like 500 GPa), it's postulated to be metastable -- like diamond, you could create it at pressure, and it might stay a solid metal at STP conditions. It's postulated to be made of atomic hydrogen -- lone H atoms, without the molecular bonds of H_2. The recombination energy H + H -> H_2 suggests [1] it's the most energy-dense chemical fuel that exists, with 20 times the specific energy of {H2 + O2}. It could allow [1] rocket engines with I_sp of 1,700 seconds -- four times higher than LH2/LOX. It's thought to be the main phase of hydrogen inside the planet Jupiter [2] and responsible for its dynamo [3] (but as an ordinary conductor, not a superconductor). It's also speculatively a structural material, one that's less dense than water [4].
It might have been created in a lab, in 2011 [4], but it's not clear.
[0] https://en.wikipedia.org/wiki/Metallic_hydrogen https://en.wikipedia.org/wiki/Metallic_hydrogen
[1] http://www.nasa.gov/pdf/637123main_Silvera_Presentation.pdf http://www.nasa.gov/pdf/637123main_Silvera_Presentation.pdf
[2] https://en.wikipedia.org/wiki/Jupiter#Internal_structure https://en.wikipedia.org/wiki/Jupiter#Internal_structure
[3] https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter
[4] http://www.nature.com/news/metallic-hydrogen-hard-pressed-1.10817 http://www.nature.com/news/metallic-hydrogen-hard-pressed-1....
- ajuc 12y agoWow, this reads like technobable from bad sci-fi :) I mean too good to be true kind.
- aqme28 12y agoWow, I never considered the concept of a planet with a superconducting dynamo. That's a fascinating possibility.
- throwaway_yy2Di 12y agoEven cooler: there's articles that claim the interiors of neutron stars are superconducting -- the current carried by proton pairs, rather than electron pairs. Maybe this is the source of magnetar dynamos. http://www.ohio.edu/research/communications/neutronstar.cfm http://www.ohio.edu/research/communications/neutronstar.cfm https://en.wikipedia.org/wiki/Magnetar#Origins_of_magnetic_fields https://en.wikipedia.org/wiki/Magnetar#Origins_of_magnetic_f...
- Xcelerate 12y agoThe metastability at STP is particularly intriguing. I wonder what quantum chemistry calculations have been performed on this material. I need to look this up, and maybe perform a few of my own! Supposing that we can actually generate enough pressure to generate metallic hydrogen at some point, I wonder what the downsides of the material would be.
- saalweachter 12y agoIt causes cancer in rats.
- throwaway_yy2Di 12y agoThat sounds like a fun weekend hack.
- Xcelerate 12y agoI mean, it would have to be its own research project haha. There's no way I could begin to get a simulation like that going in a weekend.
- 542458 12y ago> the downsides of the material would be Well, considering how energy-dense it is... As a construction material, wouldn't it be more than a tad dangerous if it ever caught on fire?
- TrainedMonkey 12y agoGiven temperature and pressure it formed at I am not sure oxidation would be a problem at all.
- andrewflnr 12y agoIt wouldn't so much catch on fire as revert to gas, straight from solid to H2. Otherwise known as an explosion. Then maybe you get burning hydrogen.
- ChuckMcM 12y agoIf it were stable at STP it would make for a hell of an explosive. Simply cracking a small piece and blam! Instant over pressure and frost bite as the phase changed sucks all that energy out of the surrounding environment.
- yxhuvud 12y agoWell, the frost bite might end when the hydrogen meet some oxygen.
- ChuckMcM 12y agoIt would be interesting to see if it would go exothermic or not. On the one hand you would suddenly have a bunch of free hydrogen atoms, presumably becoming H2 as they expanded. The pressure wave would be caused by sudden decrease in density (phase shift from solid to gas) but and in the process the new molecules would probably briefly become liquid and then gas. There would not be enough oxygen in the center of that expansion to convert to water, but on the edges of the expanding pressure wave their would be. One possible outcome would be that on the surface of the pressure wave, oxygen would combine with hydrogen to form water, but that water would then insulate the hydrogen behind it from any oxygen, stopping any further reaction. At some point thought he heat going into the phase shift is going to come out of the water, which will force it to freeze, and the as the surface area of the pressure bubble expands, its pressure will decrease until it is in equlibrium with the frozen water's surface tension. One possible outcome then is than a conversion would result in a 'pop', and the sudden appearance of an ice sphere which is filled with pure hydrogen.
- ars 12y agoFee hydrogen (atomic hydrogen) releases a tremendous amount of energy when it reacts to make molecular hydrogen (H2). Far far more than reacting with oxygen. So the oxygen part is pretty irrelevant when analyzing this.