First of all I want to say that I am a *scrub* in relativity so when people say things like that the universe expands and/or inflates I still don't get the full grasp of it. Here is my question. When we refer to a vacuum I would expect it to be a region of space that has absolutely no particles (fermions like the electron or bosons like the photon). But what about the gravitational field and its particle the gravitron, is it possible to make a region of space that has absolutely zero gravitational field? Since we cant shield the gravitational field there is no way to construct the perfect "true" vacuum as I say in the title of the thread. Is the perfect true vacuum in the "hypothetical" region of space that the universe hasn't expanded yet there. Like if we imagine universe is a sphere with a diameter of 100bilion light years (just saying I don't have accurate info on what are the estimates for the diameter of the universe), is the perfect true vacuum somewhere in a region outside that sphere, in a radius say of 101 billion light years? Also if someone can recommend me a good book on the Universe Evolution ( birth (matter and antimatter), growth (formation of dust clouds, stars/planets/comets, galaxies cluster of galaxies e.t.c) and possible death of the Universe).