empty space vs voidness

empty space

noun
  • A feeling of longing for someone or something that is gone; a sense of a thing's absence. 

  • Vacuum; a space containing nothing at all 

  • An unoccupied space where something may be stored 

  • An unoccupied area or volume. 

voidness

noun
  • The state or condition of being void. 

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