If space is not actually a void, then there's something shooting around in it, I'm guessing a lot like molecules in a gas. Could we apply a $(PV/T = k)$ -like gas law to it. Obviously we're not measuring a regular everyday gas but some theoretical "fluid" that we don't know enough about yet. Also regular radiation might also be part of the total pressure, and there's a wikipedia article on that.
What are your thoughts on this?
If there is such a fluid, and it obeys the gas law, then there's either an infinite amount of this fluid in our currently observable universe or the universe is finite in volume.