In
1924 the spin of the electrons was discovered, an angular momentum, a rotation
of the electron on itself at a speed close to that of light. Consequently, in
quantum mechanics the momentum of the spin cannot be considered equal to zero
and the extended energy-momentum-mass equation of special relativity is
required, with its uncomfortable retrocausal solution. The first equation that
combined special relativity and quantum mechanics was formulated in 1926 by
Oskar Klein and Walter Gordon. This equation has a retrocausal (advanced waves)
and a causal (delayed waves) solution. The second equation, formulated in 1928
by Paul Dirac, has two solutions: electrons and neg-electrons (now named
positrons) that propagate backwards-in-time. Positrons were experimentally
observed in 1932 by Carl Andersen.
The Vital Needs Theory - page 4