Researchers have been chasing the dream of metallic hydrogen for decades, ever since the material was first theorized by Princeton University scientists Eugene Wigner and Hillard Bell Huntington in 1935. If it exists, metallic hydrogen could fundamentally transform the way we used energy. Now, two scientists claim they’ve successfully created solid metallic hydrogen, but the scientific community is not yet convinced.
Metallic hydrogen is exactly what it sounds like — pure atomic hydrogen that has been put under such immense pressure that it collapses into a shiny metal. Isaac Silvera and post-doctoral fellow Ranga Dias from Harvard subjected a sample of hydrogen to 495 gigapascals of pressure, which is around 71.7 million pounds per square inch. That’s more pressure than it would experience in the center of the Earth. The pair claim the material that resulted from this process is the fabled metallic hydrogen.
To exert all that pressure, the scientists used a device known as a diamond anvil cell that compresses a sample between two diamond surfaces. However, they could not use just any diamond. The imperfections in polished synthetic diamonds could cause them to break or allow hydrogen to diffuse through the structure. The solution was to shave a five-micron layer off the diamond surface to remove imperfections and then coat it with alumina.
Silvera and Dias claim they’ve created metallic hydrogen based on their measurement of pressure and the formation of material that matches the expected properties of metallic hydrogen. They have not, however, performed any more rigorous tests on the sample. This is what most scientists who have evaluated the peer-reviewed paper (published in Science) have called for, worrying that the shiny material created in the anvil could just be alumina from the diamonds. Silvera and Dias say they do intend to do this, but they were waiting for publication first. They worry the sample could be destroyed by additional testing, so it has been preserved in a cryostat container until publication.
If the presence of metallic hydrogen is confirmed, this could change numerous industries. Metallic hydrogen is believed to be a room-temperature superconductor. That means it has zero electrical resistance, making it ideal for the construction of super-efficient batteries and electrical systems that don’t lose any energy to heat. Metallic hydrogen could also be used as a fuel source, as it retains all the energy used to compress it into a metallic state. Metallic hydrogen returning to regular molecular hydrogen would release a huge amount of energy, which could be used to propel a rocket.
There’s still more work to do in order to confirm the presence of metallic hydrogen, but this could be an amazing advancement. Even if it turns out to be real, this is just a tiny sample and all that exists on Earth. Making enough metallic hydrogen to be useful could be a completely different problem.
Now read: What are superconductors, and when will we all get maglev trains and unlimited electrical power?