scintillation

Short definition from Wiktionary

Noun

1. 1
   A flash of light; a spark.
2. 2
   The twinkling of a star or other celestial body caused by turbulence in the Earth's atmosphere.
3. 3
   The flash of light produced by something (especially a phosphor) when it absorbs ionizing radiation.
4. 4
   A brief expression that is amusing or clever; witticism.