blue flash (English, noun)
expansion: blue flash (plural blue flashes)
Senses:
topics: astronomy
climatology
meteorology
natural-sciences
glosses: A very rare phenomenon observed in the morning or evening when the sun is crossing or immediately below the horizon, in which a momentary flash of blue light appears above the upper rim of the solar disk, caused by refraction of light in the atmosphere.
qualifier: nuclear physics
glosses: A phenomenon sometimes observed when a criticality accident occurs in nuclear materials, inducing a discharge of radiation into the environment.
Forms:
form: blue flashes
tags: plural