Tunnelling and Solidity Misconceptions: Bohr, Orbitals, and Why You Don't Fall Through the Floor

Corrections around tunnelling, solidity and atomic structure — including the ones that show up in confident internet explanations of why you cannot fall through the floor. ## About why you don't fall through **"Your atoms might miss the floor's atoms" is wrong at the premise.** There is no aiming and no missing. Matter is mostly empty space, and what stops you is electromagnetic repulsion between electron clouds plus the Pauli exclusion principle. Solidity is a force field, not a traffic jam of tiny balls. See Why Solids Are Solid: Electron Repulsion and the Pauli Exclusion Principle. **"The Bohr model was disproven, therefore tunnelling is nonsense" is a non-sequitur** — and it is the most common confidently-wrong reply to this question. The conclusion ("you won't tunnel through the floor") happens to be right, but the reasoning is backwards: **the wave picture is exactly what makes tunnelling possible in the first place.** Retiring the planetary model strengthens the case that tunnelling is a real phenomenon; the reason the answer is still no comes from the barrier maths, not from Bohr being outdated. See Can You Tunnel Through the Floor? The Compound Probability and the Barrier Maths. **Dismissing the tunnelling discussion as "treating physics like sci-fi" is itself the overreach.** Barrier tunnelling is textbook quantum mechanics with daily industrial application — scanning tunnelling microscopes, flash memory, tunnel diodes — and active experimental research into tunnelling by increasingly massive systems. ## About electrons **"Electrons aren't really particles at all" is an overcorrection.** The accurate framing is wave–particle duality; in the deepest modern view, electrons and photons are both excitations of quantum fields. Saying electrons "have more in common with photons" is misleading — an electron is a massive, charged, spin-½ fermion and a photon is a massless, neutral, spin-1 boson. They are about as different as two field excitations can be. **"Corpuscule" is not a neutral term.** It is Newton's archaic word for a particle of light and leans toward the particle picture, so it does not sidestep the duality. **Electrons in orbitals are not circling the nucleus.** In a stationary state there is no orbiting. s-orbitals have *zero* orbital angular momentum (ℓ = 0) — a picture of waves "going round multiple times" is itself semi-classical, and wrong. **Electron probability is not uniform around the nucleus.** Probability density is highly structured: radial maxima and nodes, angular nodes, and the distinct shapes of s, p, d and f orbitals. "Equal probability in all directions" is wrong even for s-orbitals in the radial sense. ## About the tunnelling maths **Objects don't tunnel as units.** Each atom tunnels independently, and a macroscopic event is the joint probability of all of them doing it at once. This is *why* the numbers are absurd — it is the product of ~10^26 tiny probabilities, not one mysteriously small number. **Single-atom tunnelling through a floor is not meaningfully "more likely".** It beats the whole-foot event only in the sense that 10^−100000000 exceeds 10^−(10^30). Both round to never. **The bond, not the gap, is the gatekeeper.** An atom must first break a several-eV chemical bond to leave your body at all — a thermal process, not tunnelling. Analyses that jump straight to barrier penetration skip the step that actually sets the rate. ## About what tunnelling really does **Atom tunnelling is real but goes nowhere net.** Hydrogen in metals, the ammonia inversion, cryogenic surface diffusion and heavy-atom tunnelling in chemistry are all measured. Without a bias or an absorbing trap they are random walks with no net transport. See Atom Tunnelling in Real Systems: Hydrogen in Metals and the Ammonia Inversion. **Body radioactivity is not tunnelling.** The ~7,000–8,000 decays per second in a human body come mostly from potassium-40 and carbon-14, which decay by beta emission and electron capture — weak-force processes. Alpha decay is the tunnelling one, and alpha emitters are only trace constituents of the body. **Sliding surfaces really do transfer atoms — mechanically.** Adhesive wear transfers material atom by atom at asperity junctions. Real, but tribology rather than quantum mechanics. See Adhesive Wear: How Sliding Surfaces Transfer Atoms.