Re-creating the Cap/Bucky fight, of course, requires us to also figure out how Cap works.

(Note: This means that my roommate is humoring me in discussions now. You should not do this. Moggie learned early on that it is a bad idea to engage me on any idea you really think is too crazy to put into practice. I am too dumb to understand what stuff I'm not supposed to be able to teach myself.)

The shield is a particular sticking point. Cap's fighting style, while creative, is nothing you can't figure out with a reasonable amount of enthusiasm and athleticism. The thing is, you can't actually do what it looks like you're doing, because no real world material behaves like Cap's shield.

Captain America's shield is made of a vibranium steel alloy. Materials that experience elastic collisions compress into the point of impact and then expand back to their original shape, i.e., they bounce. Materials that experience inelastic collision dissipate kinetic energy into deformation, i.e., they go splat. Vibranium does neither; it has the magic property of absorbing all vibration, experiencing neither an elastic nor an inelastic collision as we recognize them. The comics say that the kinetic energy so stored goes into strengthening the bonds within the crystal structure of the metal, which is scientific rubbish, but not specific enough rubbish to really argue with, so we'll just let that go.

The point is that the shield, unlike a similarly shaped piece of steel or aluminum, doesn't bounce or rattle at all. It's still subject to friction, which is how Steve gets it to bank off of things -- it hits, and instead of losing energy to its own deformation, it deforms whatever it hits, and kicks off again in the direction of its spin. If it deforms the target enough, there isn't anything to kick off of, and it embeds itself into the material (or blows straight through, if the target is fragile enough); if it's subject to enough friction while moving, it eventually slows to a halt. If he landed hard on it from a long drop and didn't grind it across the highway, the energy of the impact would just reflect back through the shield and into him and break most of his super-soldier bones anyway.

There are a few interesting implications with regards to heat as well. Heat is just vibration on a molecular level. Since vibration makes the bonds stronger rather than weaker, they must have formed the initial alloy ingot by applying colossal pressure at ambient (or even very cold) temperatures over a very long period of time, until the metal slowly flowed into the shape of the mold. The final shaping would have to be done via friction, possibly using a pure vibranium shard as a grinding wheel. The surface of the shield has concentric brush marks, so it was probably done on a lathe. The surface color, particularly the translucence and the way bullets can scar it without mechanically damaging the shield beneath, looks like it was done via anodization, which is an electrochemical process and probably works all right even on vibranium.

Although the metal itself would have to be forever "cold" in an absolute molecular sense -- and, in that sense, colder and more rigid the more energy it absorbs -- its vibration-reflecting property would bounce nearby heat emissions right back to the source. Pure vibranium would feel as if it were at either ambient or body temperature, whichever is higher. Cap's shield, being partly steel, would continually absorb small amounts of environmental heat, and stash it away in the neighboring vibranium lattice. At any temperature Steve could likely survive, his shield would always be faintly cool to the touch. And every time he lays his hands on it, it becomes just a little bit stronger.

Using it as a death-frisbee as Steve tends to do would basically turn the shield into a force bolt, plus bonus inertia from the mass. (In the comics, when the shield was damaged, he did use a pure energy force shield for a while. He likes having the metal one back, thankyouverymuch.) Since it absorbs no kinetic energy, whatever kinetic energy he gives it at the moment of release is transmitted directly to the target. It works brilliantly on most people. Nothing but vibranium ever behaves like that, and since Cap has pretty much all of the vibranium available outside of Wakanda, it's not even possible to train anyone to counter it.

On the other hand, if you can tank the full impact of the throw, as the Winter Soldier can, and grip the shield hard enough to stop the spin, you can yank it right out of the air without even a hint of reverberation. Surprised the fuck out of Steve; no one else has ever figured out they can do that. Although it does bode well for when he gets his brains back and the two of them can partner up again. If his arm is tough enough to take the impact of the shield edge, that means Steve can bank it off an accomplice who can adjust its trajectory at will.

Implications for stage fighting are... annoying. If we want it to look right, I'd have to figure out how to pull my strikes in a non-obvious direction, and she's going to have to just absorb any impact I can't cheat. That'll take some planning.


  1. "Nothing but vibranium ever behaves like that, and since Cap has pretty much all of the vibranium available outside of Wakanda, it's not even possible to train anyone to counter it."

    (Incidentally, in the comics Echo has a fighting staff with "a sliver of vibranium" after she moves to LA and works with Moon Knight. He subsequently gets her killed but there's still a partly-vibranium staff floating around somewhere.)


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