- A broad glowing arc, sometimes seen high in the western sky at twilight,
caused by fine particles of dust scattering light in the upper atmosphere.
PHENOMENA AND STRUCTURES
- Lingering radiation, also called postluminescence,
that remains after an event such as a gamma-ray
burst (which has an X-ray afterglow) or the Big Bang (the afterglow
of which is the cosmic
microwave background radiation). The term is also used as an alternative
name for phosphorescence.