How many electron positron pairs are created every second in a cubic meter of vacuum?
Don't these virtual partials pop in and out of existence in a vacuum?
Google "quantum foam" and you'll see the speculative nature of that theory.
Quantum foam does seem very speculative but aren't these particle antiparticle pairs responsible for vacuum fluctuations?
The short answer is that you've been lied to. No theory describes the vacuum as that "sea of particles constantly popping into and out of existence" that popsci authors (and some overly romantic actual-sci ones) seem to like so much.
I think that these could help:
The vacuum state, by definition, is the one state in QFT which is absolutely stable, and nothing pops in and out of existence, because it's the ground state, the state of lowest energy. If there's no energy above the ground state there's nothing excited which could pop out of existence again nor can there be anything pop into existence spontaneously, because energy is conserved.
In normal language, the word "fluctuation" means "variation with time". In QM language, it's more like a synonym for "uncertainty" or "indefiniteness." Vacuum fluctuation does not involve variation with time.
Separate names with a comma.