Whenever I attempt to research this question, my search results yield "Is the Universe Infinite" where the question ALWAYS refers to the volume of the universe. This question is usually answered along the lines of: "If the universe is closed, than it's volume, aka it's 3D surface area in 4-space, is finite, otherwise if the universe is 'flat' or 'open' it's volume is infinite." And yes, I'm aware that's a crude nutshell version of the answer. The question I've always wondered is: "Is the mass of the universe finite." I've come across statistics that measure "how many atoms are in the universe," but upon further inspection they always mean "in the observable universe." Do we in fact know whether or not the mass of the entire universe (including the unobserverable universe) is finite?