The Black Panther is set to make his solo big screen debut in the Marvel Cinematic Universe, and the broader, non-comic book reading public is about to be introduced to the technologically advanced country of Wakanda. The wealth of certain nations is correlated with the natural resources found within its borders. Think of the oil-rich countries in the Middle East, or the abundant timber forests of Canada. In the Marvel universe, one of the most fortunate countries on the face of the planet is Wakanda, for in these lands an extra-terrestrial meteorite landed, depositing a rich load of an extremely rare and valuable mineral – Vibranium.
As suggested by its name, vibranium’s unique properties relate to how the atoms in this material process external sources of vibrations. In particular, vibranium is a perfect shock absorber, converting the kinetic energy and atomic vibrations from any projectile into non-lethal forms of energy. The king of Wakanda, T’Challa, defends his country as the superhero the Black Panther, wearing a suit composed of vibranium, that provides head-to-toe bullet-proof shielding. The kinetic energy of a bullet will ordinarily cause such extreme atomic vibrations that the chemical bonds holding together the outer uniform will be broken, and the bullet will penetrate through to your body, causing comparable damage. When a bullet strikes a vibranium suit, on the other hand, its kinetic energy is presumably rapidly shunted away from the point of impact, and transformed into a less destructive form. While vibranium does not exist in our more mundane, non-superhero world, there are real-world materials that can approximate these amazing properties.
A simpler term for vibrating atoms is ‘sound,’ and all matter, whether vapor, liquid or solid, is able to transmit sound waves. How easily sound can propagate through an object depends on such details as its density and the strength of the connections between neighboring atoms. Sound moves much faster (in general) through a solid than through air – which is why you’ll hear the approach of the distant train much sooner if you feel the locomotive’s vibrations through the steel rails, rather than waiting for the sound to reach you through the air.
It requires energy to generate a sound wave – propagating regions of pressure or density modulations, and sound can be damped if the energy of the atomic vibrations can be deflected into other directions. The sound in the steel rail does not continue forever – some of the atomic vibrations transfer their energy to the surrounding air, which then carries some of the sound’s energy away from the metal. When enough energy is transferred, the amplitude of the sound’s vibrations becomes comparable to the atomic vibrations that all matter at a given temperature has, and the sound will have dissipated.
So, one way to make a ‘bullet-proof’ analog of vibranium is to make a material that transmits the localized kinetic energy of an incoming projectile away from the point of impact before the atomic vibrations are able to break the chemical bonds holding the material together. A good rule of thumb will be – the faster the speed of sound in a material, the harder it will be to penetrate the material with an external projectile. Recent studies of graphene, a unique ultra-thin form of carbon that is only one atom thick, where the carbon atoms are arranged in a honeycomb, hexagonal pattern, find that its speed of sound is extremely high. Consequently, much more energy is needed to penetrate multiple layers of graphene, compared to a comparable mass of lead, or even Kevlar.
But sweeping the atomic vibrations away from the point of impact will protect the region where the external kinetic energy first strikes the graphene, but that energy is still present in the material. One way to handle these vibrations is to convert them into another form of energy that is less harmful to the material (and any person wearing such a super-suit). There is a phenomenon termed ‘sonoluminescence’ where sound waves are converted into light. The energy of a sound wave is typically many times smaller than the energy in a beam of light, so this is one way that a large amount of kinetic energy due to an impacting projectile could be transformed into a non-lethal form.
In the Black Panther film, we learn that the Panther’s sister Shuri, a scientific genius who’s skills rival Tony Stark’s, has refined the Black Panther suit so that it can store incident kinetic energy, and release it in a single focused blast. Perhaps the suit has a series of fiber optic cables woven into its fabric, so that the light generated by the sonoluminescent process can be carried off and stored in some sort of ‘optical battery,’ to be dramatically discharged at some later time. I certainly could not design and fabricate such a suit and mechanism but someone Shuri can!