nebula General term used for any "fuzzy" patch on the sky,
either light or dark; a cloud of interstellar gas and dust.
neutrino An electrically neutral elementary particle that is one
of the products of nuclear fusion reactions. Neutrinos have
little or no mass, move at close to the speed of light, and
interact very weakly with matter. neutrino oscillations Possible
solution to the solar neutrino problem, in which the neutrino
has a very tiny mass. In this case, the correct number of
neutrinos can be produced in the solar core, but on their way to
Earth, some can "oscillate," or become transformed into other
particles, and thus go undetected. neutron An elementary
particle with roughly the same mass as a proton, but which is
electrically neutral. Along with protons, neutrons form the
nuclei of atoms. neutron capture The primary mechanism by which
very massive nuclei are formed in the violent aftermath of a
supernova. Instead of fusion of like nuclei, heavy elements are
created by the addition of more and more