Harvard researchers have succeeded in producing the rarest, and potentially
one of the most precious, minerals on the world, over a century after it was
first imagined.
Isaac Silvera, a professor of natural sciences at Thomas D. Cabot
University, and postdoctoral researcher Ranga Dias invented the substance,
called atomic metallic hydrogen. The substance is predicted to have a wide
range of uses, including as a superconductor at room temperature, in
addition to aiding researchers in understanding fundamental concerns about
the nature of matter. An article that appeared in Science on January 26
describes how the unusual substance was created.
This is the pinnacle of high-pressure physics, according to Silvera. It is
the first sample of metallic hydrogen ever found on Earth, so anything you
see when you look at it is brand-new.
It was produced by Silvera and Dias by compressing a little sample of
hydrogen to a pressure of 495 gigapascal, or more than 71.7 million pounds
per square inch, which is higher than the pressure in the Earth's core.
According to Silvera, solid molecular hydrogen, which is made up of
molecules on the solid's lattice sites, breaks down at very high pressures,
and the firmly bonded molecules dissociate to change into atomic hydrogen,
which is a metal.
The study provides a crucial new insight into understanding hydrogen's
general characteristics, but it also provides intriguing suggestions about
potentially ground-breaking new materials.
One crucial prediction, according to Silvera, is that metallic hydrogen
will be meta-stable. Accordingly, if the pressure is released, it will
remain metallic, much like how diamonds develop from graphite when subjected
to high heat and pressure yet continue to be diamonds when the pressure and
heat are released.
According to Silvera, it is crucial to know whether the substance is stable
because it has been predicted that metallic hydrogen may function as a
superconductor at ambient temperature.
He declared, "That would be revolutionary." "Up to 15% of energy is lost
during transmission due to dissipation, so if wires made of this material
could be used in the electrical grid, that narrative might change."
A room temperature superconductor, one of physics' holy grails, might,
according to Dias, fundamentally alter our transportation system by enabling
magnetic levitation of high-speed trains, enhancing the efficiency of
electric automobiles, and enhancing the functionality of several electronic
gadgets.
Since superconductors have no resistance, energy might be saved by
sustaining currents in superconducting coils and then used as needed thanks
to the material's potential benefits in energy generation and storage.
Metallic hydrogen, the most explosive rocket fuel yet found, may play a
crucial role in assisting mankind in exploring the furthest reaches of space
even if it has the potential to change life on Earth.
Metallic hydrogen can only be created by using a vast amount of energy,
according to Silvera. It becomes the most potent rocket propellant known to
man and might completely change the field of rocketry if it is converted
back to molecular hydrogen.
The "specific impulse" (a measure of how quickly a propellant is blasted
from the rear of a rocket in seconds) of the most potent fuels currently in
use is 450 seconds. In contrast, it is predicted that metallic hydrogen has
a particular impulse of 1,700 seconds.
You could easily explore the distant planets with it, Silvera suggested.
The ability to launch heavier payloads and launch rockets into orbit with
only one stage as opposed to two makes this possibility highly
significant.
Silvera and Dias used diamond, one of the world's hardest materials, to
make the novel substance.
Silvera and Dias, however, employed two tiny pieces of meticulously
polished synthetic diamond that were subsequently treated to make them even
harder and positioned opposite each other in a structure known as a diamond
anvil cell in place of real diamond.
Diamond powder is used to polish diamonds, and this process can remove
carbon from the surface, according to Silvera. "We discovered flaws in the
diamond using atomic force microscopy, which could lead to it weakening and
breaking."
He suggested using a reactive ion etching procedure to remove a thin layer
off the diamond's surface that was about five microns thick, or roughly
one-tenth of a human hair. A thin film of alumina was then applied to the
diamonds to stop the hydrogen from soaking into their crystal structure and
weakening them.
After more than 40 years of research and over a century after it was
initially postulated, Silvera said it was exciting to witness the substance
for the first time.
It was a lot of fun, he remarked. 'Ranga was running the experiment, and we
believed we may make it, but when he called and said, 'The sample is
glowing,' I sprinted over there and saw metallic hydrogen.
We changed the lab because "I said right away that we have to make the
measurements to confirm it," he added. It's a remarkable accomplishment, and
even if it only exists under extreme pressure in this diamond anvil cell,
the finding is basic and transformational.
Provided by
Harvard University
