Larger objects, such as the rogue (not members of a solar system) rocks you mention, are classed as MACHOs (massive compact halo objects) in possible dark-matter explanations.
Recent studies [0][1] have pretty much ruled out MACHOs as an explanation, by looking for gravitational microlensing events by MACHOs between us and the Magellanic Clouds and Andromeda Galaxy. They found about 1/1000 of the events predicted by a quantity of MACHOs necessary to explain dark matter's effect on our galaxy's gravity. For very small MACHOs that wouldn't produce enough lensing to be detectable, then you need so many that they'd darken the light, like a gas/dust nebula. This is also not observed.
I don't work in the field, but I studied astrophysics, and I have one or two astronomer friends - it seems these results are regarded as a pretty definitive nail in the MACHO theory's coffin. Current research is mostly looking for WIMPs (weakly interacting massive particles), a novel class of fundamental (atomic/subatomic?) particle, expected to be present throughout all of space, which doesn't interact with the electromagnetic force, so doesn't interact with light, including virtual photons of attraction and repulsion, (such as those holding the particles of your feet together and also repulsing your feet from the ground right now,) that mediate the forces we interpret as "solidity" and "pressure", but has mass.
Thanks for the explanation. It raises other questions, like how they would know small MACHOs haven't darkened the sky (I'm guess either you'd see twinking or it'd shift the stars downward on the Hertzsprung–Russell diagram to some "unnatural" location) - but I get the gist of it. It's an interesting area of research. Really appreciate you illuminating it for me :)
Sorry to be a pendant, but the forces holding things together is just ordinary EM (well, QED probably better stated) while virtual photons are different (virtual since they only appear in higher order corrections in qft).
I love pedants, don't apologise! Happy to be corrected and keep learning. It's been quite a few years since I was in physics classes, so I went and looked this up, and I think my memory was right, as for example, descriptions of the Coulomb force (electrostatic repulsion and attraction as in my foot example) all seem to be phrased in terms of virtual boson exchange.
I agree the forces holding things together is "ordinary EM", but virtual particles as force carriers seems to be ordinary, not rare.
Recent studies [0][1] have pretty much ruled out MACHOs as an explanation, by looking for gravitational microlensing events by MACHOs between us and the Magellanic Clouds and Andromeda Galaxy. They found about 1/1000 of the events predicted by a quantity of MACHOs necessary to explain dark matter's effect on our galaxy's gravity. For very small MACHOs that wouldn't produce enough lensing to be detectable, then you need so many that they'd darken the light, like a gas/dust nebula. This is also not observed.
I don't work in the field, but I studied astrophysics, and I have one or two astronomer friends - it seems these results are regarded as a pretty definitive nail in the MACHO theory's coffin. Current research is mostly looking for WIMPs (weakly interacting massive particles), a novel class of fundamental (atomic/subatomic?) particle, expected to be present throughout all of space, which doesn't interact with the electromagnetic force, so doesn't interact with light, including virtual photons of attraction and repulsion, (such as those holding the particles of your feet together and also repulsing your feet from the ground right now,) that mediate the forces we interpret as "solidity" and "pressure", but has mass.
[0] https://sites.astro.caltech.edu/~george/ay20/eaa-wimps-macho... [1] https://www.nao.ac.jp/en/news/science/2019/20190402-subaru.h...