I'm just speculating, and I'm no expert in physical theories, but, I did major in philosophy and I really want to believe that gravity is responsible for cooling things down (maybe not very much) just enough to be real and solidified. It would make sense IMO to explain how extremely small things like atoms are cooled much more rapidly than large things. Imagine if we came across a particle the size of jupiter, I'm guessing that it would be EXTREMELY rare to find one of these, and my reason in believing that is that it would decay EXTREMELY fast. Maybe, somewhere out there, we can find a Higg's particle the size of Jupiter pop into existence and almost immediately decay. That would be a very strange thing to see, and a very interesting thing to talk about.