In the previous post, I briefly mentioned that Ultra-Dense Deuterium (D(0)) has several remarkable properties in common with theorized properties of metallic hydrogen. It is important to keep in mind that these properties are difficult to confirm because D(0) has not been produced in bulk. Quantities that can be readily created are in the nanogram range.
The first property, from which it’s common name derives, is D(0)’s incredible density. Because of the inter-atomic bond distance of only ≈ 2.4 picometers, if a bulk sample of D(0) could be created its density is estimated to be in the range of 130-140 kg per cubic centimeter. This is more than 5 order of magnitude more dense than water, and roughly 1/10 th the density of a white dwarf star.
With this property, there is a caveat because the structure of ultra-dense deuterium is not known. There have been two possible proposals for the structure of D(0) and neither suggests a continuous lattice that many typical solids demonstrate (like metals or glass) a polymeric form (like plastics and wood) or even a stable periodic form (most other solids). As such it is most likely that a bulk-material would exhibit a less close-packed liquid or even gas-like form with a lower (though still astonishingly high) density.
This exceptional density means that D(0) is the more energy dense conventional (non-nuclear) material, because, being made of hydrogen, it can be burned in air. For this reason, it could prove to be a revolutionary rocket fuel.
The second property that Holmlid has reported in D(0) is superfluidity, a property previously observed only in very cold liquid helium. Superfluids are a form of matter with zero viscosity. This means that if one had a cup full of a superfluid, and stirred it in some direction, it would continue to spin in that direction indefinitely, implying that it effectively has zero friction. A truly frictionless surface has several obvious engineering applications, and would undoubtedly allow for the construction of more efficient machinery.
Having a cup of superfluid would be impossible because of another property of superfluids. Zero viscosity combined with a non-zero surface tension means that the meniscus of a superfluid is infinite, so it is able to escape from any container that it is contained within and flow to the lowest available point, even if blocked by a wall. This effect has been well demonstrated along with other remarkable properties of superfluids (such as the ability to create unpowered and continuously running fountains) using superfluid helium.
Another notable property of D(0), and perhaps the most potentially useful is superconductivity. A superconductor has zero resistance, meaning it is able to carry an electric current without the loss of any energy. The most obvious application of superconductors is for improving the efficiency of electronics and the electricty distribution system. Because loops of superconductors can carry an electric current in circles indefinitely it can also be used to create very strong permanent magnets and has been the basis of several proposals for “maglev” trains, and is already utilized for devices such as MRI which require exceptionally strong magnetic fields that can be turned on and off.
Many materials are superconductive, including many common metals and metal salts, however, this superconductivity can only manifest below materials’ “critical temperature”. Over the last few decades, there has been extensive work towards developing materials with higher critical temperatures, however, progress has been slow and sporadic. The materials with the highest critical temperature until recently have been the “cuprates”, which have a critical temperature above the temperature of liquid nitrogen. The highest recorded critical temperature is -135 celsius, and it is this low temperature of operation that hinders the large-scale application of superconductors. What makes D(0) remarkable is that it appears to be superconductive at standard temperature and pressure.