empyreal vs superterrestrial

empyreal

adj
  • Of the sky or heavens. 

  • Fiery, made of pure fire. 

  • Pertaining to the highest heaven or the empyrean 

superterrestrial

adj
  • Above the Earth or earthly concerns. 

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