Astronomers and various professionals have seemingly always maintained that Outer Space vacuum is a virtual 'null void' with absolutely 'nothing' in it. This always bothered me for some reason, although I could never say exactly why. It was just a nagging suspicion in the corner of my mind that there must be 'something' there, to give it dimension. Otherwise, how would the planets and stars 'know' where they are and where they're going (not to mention where they've been ((i.e. with delayed, lightspeed progression of gravity waves)) )? Now, we're being told there really are different invisible 'fields', one kind of field for each kind of subatomic particle. Momentum seems to me to be another mystery, in which these fields flawlessly endow moving objects with the energy of motion, and pass it along from 'here to there'. I feel this most intensely whenever I see something like a speeding test vehicle video that has been frozen split-seconds before impact, then moved forward in ultra slow motion. As if magically, the vehicle exhibits giving up the 'stored energy' of all that mysterious, invisible, magical 'momentum' as it smashes into the barrier.
As for 'empty Space', then there's also the fact that if you can look in any direction and see stars and galaxies, it means the photons are interpenetrating every supposedly 'empty' patch of Space. Also, I have a suspicion that FTL travel still awaits pending the discoveries of future super science breakthroughs.
^Lightspeed gravity waves virtually guarantee that stars and galaxies will always be drawn to where their neighboring counterparts were before in the more immediate past, not where they actually are at any given moment, resulting in trail-chasing and swirls, as with Grand Design spiral galaxies, instead of direct head-on collisions.
With the concept of invisible and all but undetectable sub-atomic particle fields pervading all of outer space, what seems significant to me is the idea that 'momentum' may belong more properly to the fields, rather than to the solid matter. Of course, I speak conversationally out of the relative ignorance of a layman and astronomy enthusiast.