scintillate vs shimmer

scintillate

verb
  • To give off sparks; to shine as if emanating sparks; to twinkle or glow. 

  • Of a star or other celestial body: to vary rapidly in brightness; to twinkle. 

  • Especially of a phosphor: to emit a flash of light upon absorbing ionizing radiation. 

shimmer

verb
  • To shine tremulously or intermittently; to gleam faintly. 

noun
  • A measure of the irregularities in the loudness of a particular pitch over time. 

  • A faint or veiled and tremulous gleam or shining. 

  • A thin electronic device that is fit inside a card reader, such as on automated teller machines (ATMs), or point-of-sale terminals (POS's), that acts as an intermediate interface between the chip on a chip-and-pin technology card and the chip reader of the machine, to allow one to clone the chip. 

How often have the words scintillate and shimmer occurred in a corpus of books? (source: Google Ngram Viewer )