Discovery of an Ionizing Radiation Field in the Universe
  We draw attention to observational evidence indicating that a substantial
fraction of the well-known cosmic celestial diffuse ultraviolet background
radiation field is actually due not to dust-scattered starlight, but
rather---considering its spectral character at most locations in the sky---has
an unknown physical origin. We arrive at this conclusion from re-examination of
spectra of the diffuse ultraviolet background that were obtained---long
ago---using the ultraviolet spectrometers aboard the two Voyager spacecraft,
which were located far out in our solar system, and at very different
locations. As there is neither a reasonable nor even an unreasonable
conventional astrophysical source for this newly-identified fraction of the
radiation, we are led to speculate that the photons that we observe have their
origin in the very slow decay of the particles that make up the ubiquitous dark
matter, which we know envelopes our Galaxy. Whether or not that actually is the
source, this new radiation field extends somewhat below 912 {\AA}, so we have
found, at last, the radiation that re-ionized the universe.
