blue flash

English

Noun

blue flash (plural blue flashes)

1. (meteorology, astronomy) 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.
2. (nuclear physics) A phenomenon sometimes observed when a criticality incident occurs in nuclear materials, inducing a discharge of radiation into the environment.

See also

• green flash

Anagrams

• flushable