Atom center of mass, although strictly speaking these particles are believed to be point-like and cannot be said to be rotating. Spin is measured in units of the reduced Planck constant (ħ), with electrons, protons and neutrons all having spin ½ ħ, or "spin-½". In an atom, electrons in motion around the nucleus possess orbital angular momentum in addition to their spin, while the nucleus itself possesses angular momentum due to its nuclear spin. The magnetic field produced by an atom—its magnetic moment—is determined by these various forms of angular momentum, just as a rotating charged object classically produces a magnetic
Captain Atom not mentioned in the panel in which they appear, but the Captain Atom is visually similar to Charlton's original version of the character. However, according to comments by Grant Morrison, this alternate universe is not the pre-Crisis Earth-4. 2007's "" features Captains Atom from alternate universes. The combatants of the series are introduced as a new Breach of Earth-8, a Ronnie Raymond/Nathaniel Adam fusion called "Quantum-Storm" from Earth-37, and another from Earth-38 who rules over his Atomic Knights. Additionally, issue #1 introduces a "Brigadier Atom" from Earth-13 married to Nightshade, and in "Countdown: Arena" #3, Breach gathers together a group