|
Definition of Blue flash
1. Noun. (meteorology astronomy) A very rare phenomenon observed in 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. ¹
2. Noun. (nuclear physics) A phenomenon sometimes observed when a criticality incident occurs in nuclear materials, inducing a discharge of radiation into the environment. ¹
¹ Source: wiktionary.com