I'm trying to sketch out what empty space is composed of and I'm drawing a blank (pun intended). http://instantrimshot.com/ No, really though, I'm trying to wrap my head around just what exists in this newly-modeled seething foam we used to call "nothing." From what I understand, within the vacuum there is a continuous "boil" of quantum fluctuations whereby virtual particles pop in and out of existence in a process called "pair production." That's about all I'm fairly confident of at this point. I have scoured several Wiki pages trying to get a better picture of what is going on. Here are a few of those: http://en.wikipedia.org/wiki/Quantum_foam http://en.wikipedia.org/wiki/Quantum_fluctuation http://en.wikipedia.org/wiki/Dirac_sea http://en.wikipedia.org/wiki/Virtual_particle http://en.wikipedia.org/wiki/Zero-point_energy http://en.wikipedia.org/wiki/Pair_production One main question I have that I didn't get from reviewing these is whether or not anything besides electrons-positrons are involved in the pair production/quantum fluctuation process. Most specifically, do quark and anti-quark pairs pop in and out of the vacuum. None of these articles say. The closest I could get was this statement from the pair production article: From this statement it looks as though it's just leptons? Am I wrong? What about neutrinos? They are electrically neutral leptons, do they pair produce in the vacuum? One more thing. The Unruh effect. From the article: http://en.wikipedia.org/wiki/Unruh_effect If, say, pair production in the vacuum were limited to just electrons-positrons, is this what the empty space surrounding an arbitrary inertial observer would look like to an accelerating observer? A warm gas of isolated positrons and electrons in thermal equilibrium? What else might be in there?