Learn more about spacetime itself and the particles inhabiting it in the video below:
What Fills The Vast Expanse Of Space? (Video)
2. 5. 15 by Jaime Trosper
By definition, 'empty' means devoid of matter, or lacking in substance. So when most people hear the term empty space, they assume that, indeed, space is entirely empty. Once upon a time, we thought this was true, but these days, we know that space isn't a perfect vacuum. It, in fact, contains things we can't even conceive of, like virtual particles, which pop in and out of existence at a black hole's whim.