Clarification: I should have said "particle pairs" instead of just "pairs". One of the particle pairs is matter, and the other is anti-matter. And these virtual particle pairs are continually emerging from the vacuum, and then recombining and disappearing back into the vacuum. This is related to the concept of "quantum foam". For more info, see: https://en.m.wikipedia.org/wiki/Quantum_foam..."quantum foam" in which virtual matter / anti-matter pairs are constantly emerging...
So the empty vacuum of space, and indeed the space between our atoms, the space interpenetrating everything, has a subtle infinitely energetic existence, and is not just a nothingness. In fact, in this universe, there is nowhere that is a nothingness, even in the purest vacuum.
Exotic alternative energy researchers are trying to harness this so-called zero point energy, which can actually be demonstrated to exist in the lab as the Casimir Effect. See: https://en.m.wikipedia.org/wiki/Casimir_effect
Some say zero point energy has already been tapped as an energy source, but is suppressed technology because of the effect it would have on the global energy economy, and greed, of the current stakeholders. If so, that ignores the vast abundance that would result, not to mention the resolution of a wide variety if environmental issue.
The actualization of zero point energy utilization appears frequently in science fiction, like Stargate's ZPM (Zero Point Module), a technology of the Ancients. It also appears in the third "Atlas Shrugged" film, based on Ayn Rand's novel of the same name.
Finally, I'll note that for a lot us viewing TOS way back then, Star Trek was our first exposure to the idea of antimatter - I know it was for me. I learned a lot of science from Star Trek, and speculative future science - inspiration on which to dream and build the future. Thank you Gene Roddenberry!