© 2026 David R. Young — Spectrum Energy Research Foundation · CC BY-NC-SA 4.0
What determines how well a metal conducts electricity? The conventional answer points to free electrons — how many, how mobile. But a different pattern emerges when conductor metals are examined through the lens of their inner electron shells. The best conductors share a specific combination: a full, deeply buried inner shell and a single electron contributed to the conduction sea. The depth and completeness of that inner shell — not the number of free electrons — appears to be the primary variable controlling conductivity. This same variable explains why the best normal conductors are the worst superconductors, and opens a question about what happens at the superconducting transition.
When a generator produces electricity, it launches an electromagnetic wave down the conductor. That wave travels through the wire's atomic lattice at nearly the speed of light. The lattice — the rigid, repeating arrangement of metal atoms — acts as the base for this wave. The wave does not move the lattice. It rides it.
The wave's job is to push the conductor's free electrons into motion. These outer-shell electrons, shared across the entire metal in what is called the electron sea, drift through the lattice in response to the electromagnetic wave. Their movement is the current.
Resistance arises because the lattice atoms are not still. At any temperature above absolute zero, every atom vibrates randomly around its resting position. These vibrations span a broad frequency range — roughly 0.5 to 15 terahertz — with no dominant frequency. It is thermal noise, not a coherent wave. When drifting electrons collide with vibrating atoms, they lose energy. That energy becomes heat.
This is well understood. What has not been examined is what determines how much those atoms vibrate and how hard the electrons collide with them. The answer lies in a part of the atom that conventional conductivity discussions largely ignore — the inner electron shell.
In a metal like copper, each atom gives up one outer electron to the shared electron sea. What remains is a positively charged ion core — the nucleus plus all the inner electrons. The attraction between these positive ion cores and the negative electron sea is what holds the lattice together. The electron sea is not just the carrier of current. It is the glue holding every atom in place.
When current flows, the glue moves. The electron sea, which was holding the ion cores in their positions, is now being pushed through the lattice by the electromagnetic wave. The stabilising force that was holding the lattice together is simultaneously being used as the carrier of energy. Moving the glue weakens the lattice.
This observation reframes resistance. It is not simply electrons bumping into atoms. It is the lattice destabilising because its stabiliser — the electron sea — is busy doing something else.
Each copper ion core retains 28 bound electrons after giving one to the sea. These electrons are arranged in shells. The outermost bound shell — the third shell, containing 18 electrons including a full set of 10 in what is called the 3d subshell — sits right at the boundary between the ion core and the electron sea. It is the surface the sea flows past.
The character of that surface determines how the sea and the ion interact. If the surface is smooth, rigid, and complete, the sea slides past with minimal disturbance. If the surface is rough, soft, or has holes in it, the sea drags against it, disturbing the ion core and generating resistance.
In copper, the 3d shell sits very close in energy to the conduction band — closer than in any other element with a full 3d shell. Research has shown that this closeness creates coupling between the 3d electrons and the conduction electrons. That coupling actually lowers the lattice's vibrational potential energy — it makes the lattice softer, less stable, more easily disturbed.
And it gets worse with temperature. A 2022 study using photoemission spectroscopy found that at room temperature, thermal energy shakes some 3d electrons out of their shell and up into the conduction band. Each one that leaves creates a hole — an empty seat in the inner shell. These holes make the surface of the ion core rough and magnetically irregular. As temperature drops, the electrons settle back into their seats. The shell fills back in. The surface becomes smooth again.
So cooling a conductor doesn't just quiet the lattice vibrations. It simultaneously repairs the inner shell. These two effects have never been separated to determine which contributes more to the reduction in resistance.
When the best conductor metals are laid out alongside their inner shell properties, a striking pattern emerges.
The top conductors — silver, copper, and gold — all share three features: a full inner d-shell, a single electron contributed to the sea, and a face-centred cubic (FCC) lattice — the densest, most symmetrical arrangement possible, with each atom touching 12 neighbours.
What separates them is the depth of that inner shell.
Silver's 4d shell sits about 4 electron-volts below the conduction band. Copper's 3d shell sits about 2 electron-volts below. Gold's 5d shell, which should sit even deeper given gold's larger size, is pushed back up to about 2 electron-volts by relativistic effects — gold's 79 protons create such an intense nuclear charge that the inner electrons reach speeds approaching the speed of light, distorting the shell structure.
The conductivity ranking follows the depth ranking exactly. Silver is the best conductor. Copper is second. Gold is third. Deeper inner shell, better conductor.
Below the top three, the pattern continues to hold:
Aluminium has no d-shell at all. It avoids the entire d-shell coupling problem but contributes three electrons to the sea instead of one. More traffic in the sea, more crowding. It conducts at 61% of copper.
Zinc has a full 3d shell that sits deeper than copper's, but contributes two electrons to the sea. The extra traffic in the electron sea prevents it from reaching its potential. It conducts at 27%.
Nickel has a 3d shell with two holes — two empty seats. Iron has four holes. Their conductivities are 22% and 17% respectively. The more holes in the inner shell, the worse the conductor. Those empty seats are places where conduction electrons can scatter into the inner shell instead of flowing past it.
The pattern across all conductor metals is this: the best conductor is the one whose inner shell is the most complete, the most deeply buried, and the least disturbed by the current flowing past it. Not the one with the most free electrons. The one with the quietest, most stable armour around each ion core.
Silver, copper, and gold — the three best normal conductors — never become superconductors. Not at any temperature ever achieved. This is one of the most well-known unsolved puzzles in physics.
The conventional explanation is that their electron-phonon coupling is too weak. The electron sea does not interact strongly enough with the lattice to form the paired electrons that the BCS model says superconductivity requires.
But look at what makes them great conductors. Their deep, complete inner shells decouple the electron sea from the lattice. The sea flows freely because it barely interacts with the lattice structure. Minimal drag, minimal disturbance, minimal resistance.
The same property that makes them great normal conductors — the inner shell's decoupling of sea from lattice — is what prevents them from reaching zero resistance through superconductivity.
The lattice structures confirm this. The best normal conductors are all FCC — face-centred cubic, 74% packing density, 12 neighbours per atom, maximum lattice stability. The best elemental superconductors — niobium, vanadium, tantalum — are all BCC — body-centred cubic, 68% packing density, only 8 neighbours per atom, more open space, more responsive to passing electrons.
Strong inner-shell coupling to the sea: poor normal conductor, potential superconductor.
Weak inner-shell coupling to the sea: excellent normal conductor, never a superconductor.
The inner shell sits on a spectrum between these two outcomes, and nobody appears to have identified it as the single variable controlling both.
Research Note 042 established through a logical deduction that no electrons move in a superconductor — moving electrons is work, work costs energy, and the persistent current does not decay. What circulates in a superconducting ring is the electromagnetic force wave itself, traveling at the speed of light in a closed loop. The material has decoupled from the wave — the wave glides along the surface without the lattice absorbing any of its energy (Research Note 042, "The Ice Rink").
The inner shell analysis in this note proposes a mechanism for that decoupling.
At the transition temperature, the last thermal holes in the inner electron shell fill. The electrons that were thermally excited into the conduction band settle back into their seats. The inner shell becomes complete — every seat occupied, the surface smooth, rigid, and magnetically uniform.
With the inner shell complete, there are no coupling points between the lattice and the force wave. The rough spots that created drag — the holes, the magnetic irregularities, the places where conduction electrons could scatter into the inner shell — are gone. The surface the wave rides past has become frictionless.
This connects directly to the Tc/θD ratio examined in Note 042. Within a single element, every isotope transitions at the same fraction of its Debye temperature — the same fraction of its lattice's maximum vibrational capacity. The inner shell analysis offers a physical reason: the transition happens when the lattice vibrations drop below the threshold needed to shake electrons out of the inner shell. Heavier isotopes vibrate less at the same temperature (lower Debye temperature), so they reach that threshold at a lower temperature. The isotope effect follows from the inner shell completing at different temperatures for different masses.
The wave then persists because nothing is left to drain it. It is not a static state — it is a wave traveling at c. But nothing in the material responds to it, so nothing takes energy from it. The inner shell is the mechanism. The decoupling is the result. The persistent wave is the consequence.
This also explains the paradox in Section 5. Silver, copper, and gold have inner shells that are already deeply buried and nearly complete at room temperature. Their surfaces are already smooth — which is why they conduct so well normally. But "nearly complete" is not "complete." At no achievable temperature do the last coupling points disappear entirely. The inner shell never quite finishes the job. The decoupling never reaches zero. So superconductivity never occurs.
The best elemental superconductors — niobium, vanadium, tantalum — have inner shells with significant coupling to the lattice at room temperature. They are poor normal conductors. But at their transition temperatures, those coupling points close. The inner shell completes. The surface goes from rough to frictionless in a sharp transition. The wave, which was heavily drained at room temperature, suddenly has nothing to drain it. The contrast is dramatic — which is why the transition is sharp rather than gradual.
The superconductor's decoupled surface — where the force wave glides without coupling to the lattice — connects to the electromagnetic propulsion concept described in Research Notes 022 and 024. Both involve a boundary between a region where electromagnetic fields interact with matter and a region where they do not.
If the gravity=EM hypothesis proposed in Note 014 is correct — that gravity and electromagnetism are aspects of the same field at different scales — then a superconducting boundary represents a surface where that coupling can be controlled. This is already demonstrated in superconducting levitation, where the boundary between the internal zero-field state and the external field produces a measurable force with no power input.
Whether this boundary can be engineered for propulsion — creating directional asymmetry in the coupling between the internal and external field states — is an open question that depends on the undemonstrated gravity=EM premise. The superconductor provides the boundary. The premise determines whether that boundary interacts with gravity. The engineering follows only if the premise holds.
This session identified three specific research directions:
Inner shell stabilisation. If the inner electron shell is the control variable for conductivity, then engineering its stability — making it deeper, more complete, or more resistant to thermal disruption without cryogenic cooling — would reduce conductor resistance at room temperature. The s-d coupling between copper's 3d shell and its conduction band is the specific mechanism to target. Any intervention that reduces this coupling stiffens the lattice.
Superconducting transition and inner shell completeness. A testable hypothesis: the critical temperature of a superconductor corresponds to the temperature at which its inner electron shell becomes fully complete — where thermal excitation can no longer shake any electrons out of that shell. This can be checked against measured critical temperatures and known thermal excitation thresholds for d-shell electrons in superconducting elements.
Propulsion architecture. The superconducting boundary as a surface where field coupling can be controlled, with exterior electromagnetic systems providing interaction with the external field. This direction is conditional on the gravity=EM hypothesis (Note 014) and should not be developed further until that premise has stronger support.
© 2026 David R. Young — Spectrum Energy Research Foundation
Licensed under CC BY-NC-SA 4.0 for research and education. Commercial use requires a separate license from Spectrum Energy Research Foundation. Contact: secharts@proton.me
© 2026 David R. Young — Spectrum Energy Research Foundation
Licensed under CC BY-NC-SA 4.0 for research and education. Commercial use requires a separate license from Spectrum Energy Research Foundation. Contact: secharts@proton.me