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
Up An' Atom training and practice bombing missions and pumpkin bomb missions against industrial targets in Taira and Hamamatsu, Japan. Capt. Bob Lewis's crew B-9 flew it on a pumpkin bomb mission to Tokushima subsequent to the Hiroshima mission, and Lt.Col. James Hopkins and crew C-14 used it to attack Nagoya with a pumpkin bomb. "Up An' Atom" returned to the United States with the 509th CG in November 1945 to Roswell Army Airfield. From April to August 1946 it was assigned to the Operation Crossroads task force. In August 1949 it became part of the 97th Bomb Group at Biggs Air Force