Some context around my understanding:

Protons and neutrons clump together in the core of the atom due to the strong nuclear force.

Protons also repel each other, but the strength of this is not strong enough to overcome the strong nuclear force.

Because the strong nuclear force's range is limited, larger atoms become radioactive as the protons repel each other, undergoing fission.

My question is whether it would be possible for an "atom" to exist in a stable configuration with a hollow nucleus.

What I mean by this, is a spherical object, where the protons and neutrons are on the outside of the sphere, but the inside is hollow. Kind of like a ping pong ball.

Strong nuclear force would cause the neighboring protons and neutrons to attract towards the center, but the protons on opposing sides of the sphere would repel.

This should create a force that causes the "ball" or sphere to be pushed outwards. (but with the strong nuclear force to keep them from going too far outwards.

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Similar to this kind of structure, but with many more protons, neutrons and a larger diameter. Surely there would exist some kind of stable structure at a given ratio of neutrons, & protons

I couldn't find any information around this, but would love to hear opinions.


1 Answer 1


I can't prove it, but I expect such construct to be very unstable. Strong force exponentially decreases with distance between nucleons : $$F_{strong} \propto \frac {1}{r e^r}$$ So as it is pictured now, inside of structure strong force would be minuscule, and electrostatic repelling force between protons would win in effect making this "bubble" going to expand. Unless strong force between nucleons in lattice vertexes is high enough and uniform enough to compensate this outer push.

If for some reason, uniformity of strong force distribution along surface nucleons is broken (field fluctuations, etc), there would arise sort of "holes" in structure which would make such hollow sphere to collapse (same as ordinary soap bubbles collapses) into clumps of nucleons. Some of them which fly apart, analogous to the process of radioactive atom decay.

  • $\begingroup$ Great response. If the protons were far enough (meaning the structure and amount of protons/neutrons was expanded) - around the distance between two bonded hydrogen atoms, I'd could imagine that the strong nuclear force would be strong enough to keep the protons from repelling apart, but it might involve some balancing of the size of the sphere $\endgroup$
    – Albert
    Jan 12 at 10:12

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