Like modern day alchemists, scientists are attempting to transform a common element into a precious metal. This isn’t about making lead into gold, but turning elemental hydrogen into a different, never before seen form of hydrogen.
Scientists are tantalizingly close to producing the first samples of solid metallic hydrogen using powerful lasers, electrical impulses, and other cutting edge equipment. It’s no simple feat, but it could have huge implications for humanity if they’re successful.
Hydrogen is the simplest of elements, consisting of just one proton and one electron. It exists in huge quantities in stars as it’s slowly fused in helium, and then into heavier elements. Like other gaseous elements, hydrogen can change phases based on temperature and pressure.
Scientists propose that metallic hydrogen could be the holy grail of superconductors, a class of materials that can transmit electrical charge without impeding it at all.
Superconductors already exist, and are used on machines like MRIs and the Large Hadron Collider. They only work when cooled to very low temperatures, though. Metallic hydrogen could theoretically act as a superconductor at room temperature.
Hydrogen is a gas at room temperature and atmospheric pressure, but it can be cooled to a liquid and even solid hydrogen ice. It’s the other direction that could lead to metallic hydrogen — extremely high temperature and pressure.
You would think that as the simplest element, hydrogen would be easy to understand. However, when subjected to high heat and pressure, the physics become devilishly complex. What we do know is that if you squeeze any element hard enough, it becomes a metal, allowing electrons to flow freely along its surface.
When you try to do that to hydrogen, pairs of hydrogen atoms begin to assemble into complex solid arrangements rather than a metal.
There are several approaches being used in the quest for metallic hydrogen to study the known forms of complex solid hydrogen. The hope is that eventually one of these techniques will result in the production of true metallic hydrogen.
The oldest method, which still shows promise, is the diamond anvil. These small devices use two tapered diamonds to exert incredible pressure of more than a million atmospheres on a sample, in this case hydrogen. This is how researchers discovered a fourth phase of solid hydrogen in 2011. Alas, it was not metallic hydrogen.
Some researchers have started using lasers to blast small samples of hydrogen, temporarily increasing the temperature and pressure to very high levels.
These experiments have shown some good evidence of metallic behavior, but it’s liquid metal. Some teams are combining lasers with diamond anvils in hopes of solidifying the liquid metal and bringing it down to room temperature.
If none of that works, researchers at Sandia National Laboratories have started using intense bursts of electrical power (the “Z Machine” shown above) to propel a metal plate into hydrogen samples at super-high speeds. If all else fails, hit it harder, apparently.
The current consensus is that metallic hydrogen exists in the solar system within gas giants like Jupiter and Saturn.
It would explain some of their unusual characteristics. If we can produce metallic hydrogen here on Earth, we may understand a lot more about the solar system and build some very cool things in the process.