As most people who have done any amount of physics know, no object is truly solid; go small enough and you will find vast amounts of space containing atoms, electrons, etc, all relatively enormous distances away from each other.
What would happen, then, if you had a truly solid object? One that, no matter how much you zoomed in, even to atomic scale, was one monolithic piece of substance (I can't even specify a substance, since that would suggest an atomic/molecular structure, which this couldn't have)? How would you even go about trying to answer this? Such an object seems to break everything I know about physics (which isn't a lot). Would any quantity of it just instantly collapse into a black hole?
Edit: The suggested duplicate question, while correcting my erroneous initial statement, doesn't answer the main question, which, as I have rightly been informed, is a 'what if' question about an object entirely comprised of solid matter (as opposed to energy occupying the 'space' within atoms)