Energetic neutral atom Energetic neutral atom Energetic neutral atom (ENA) imaging, often described as "seeing with atoms", is a technology used to create global images of otherwise invisible phenomena in the magnetospheres of planets and throughout the heliosphere, even to its outer boundary. This constitutes the far-flung edge of the solar system. The solar wind consists of ripped-apart atoms (called plasma) flying out of the Sun. This is mostly hydrogen, that is, bare electrons and protons, with a little bit of other kinds of nuclei, mostly helium. The space between solar systems is similar, but they come from other stars in our galaxy.
Discovery of the neutron integer multiple of "ħ" (the reduced Planck constant). Yet both protons and electrons carry an intrinsic spin of ½ "ħ", and there is no way to arrange an odd number (14 protons + 7 electrons = 21) of spins ±½ "ħ" to give a spin that is an integer multiple of "ħ". The Klein paradox, discovered by Oskar Klein in 1928, presented further quantum mechanical objections to the notion of an electron confined within a nucleus. Derived from the Dirac equation, this clear and precise paradox showed that a high-energy electron approaching a potential barrier has a high probability of