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martyb [soylentnews.org] writes:

nextBIGfuture is reporting [nextbigfuture.com] on the creation of Solid Metallic Hydrogen (SMH). Let that sink in for a moment. Hydrogen is the lightest of all the chemical elements. We've heard of liquid hydrogen which, when combined with liquid oxygen makes for some powerful rocket fuel. Now Some Harvard researchers have gone one step further and, for the first time ever, have created solid hydrogen! Not only that, they have confirmed that it is metallic; thus: Solid Metallic Hydrogen is now a reality. From the article:

* they have made some metallic hydrogen and have it in a cryostat in liquid nitrogen
* they might leave it under pressure and let it warm to room temperature or they could keep it cold and release the pressure
* they are planning to test for high temperature superconductivity

If it stays a metal at room temperature and after releasing pressure and was also a superconductor then it would be the holy grail of physics.

Controlled nuclear fusion, production of metallic hydrogen, and high temperature superconductivity have been listed as the top three key problems of physics. These problems all involve hydrogen and its isotopes.

Early theoretical predictions of metallic hydrogen being created at a pressure of 25 GPa (100GPa=1megabar) was way off. Modern quantum Monte-Carlo methods, as well as density functional theory (DFT), predict a pressure of ~400 to 500 GPa for the transition. The most likely space group for the atomic lattice is I41/amd. Metallic hydrogen has been predicted to be a high temperature superconductor, first by Ashcroft, with critical temperatures possibly higher than room temperature. Moreover, SMH is predicted to be metastable so that it may exist at room temperature when the pressure is released. If so, and superconducting, it could have an important impact on mankind’s energy problems and would revolutionize rocketry as a powerful rocket propellant.

From the full report on arXiv.org (pdf) [arxiv.org]:

We have studied solid hydrogen under pressure at low temperatures. With increasing pressure we observe changes in the sample, going from transparent, to black, to a reflective metal, the latter studied at a pressure of 495 GPa. We have measured the reflectance as a function of wavelength in the visible spectrum finding values as high as 0.90 from the metallic hydrogen. We have fit the reflectance using a Drude free electron model to determine the plasma frequency of 30.1 eV at T= 5.5 K, with a corresponding electron carrier density of 6.7x10²³ particles/cm³, consistent with theoretical estimates. The properties are those of a metal. Solid metallic hydrogen has been produced in the laboratory.

The report also contains images of the sample as it underwent increasing pressures — revealing changes in appearance and behavior. There are also phase diagrams showing possible pathways from SMH at low temps and high pressures to SMH at room temperature and pressure. If realized, it would totally revolutionize rocket engines, among other possibilities.

Original Submission