The Universe (or the Earth, at least) has billions and billions of particles of dust swirling around it. You can see them floating in a beam of light.
That proves that space is not empty. All of that dust has got to account for something. Has anyone estimated how much all of the dust would weigh?
What about Kirlian photography? Everthing has a force field (both around and within). Perhaps that's why the mirrors in the experiment have an "attraction" to each other.