I think 99.99% of the universe is made up of stuff we can’t touch, see, smell, or detect in any way. We can’t talk about it or even think about it. We can’t even name it. Or remember it. In fact, by tomorrow no one will remember this post. As “stuff” it is as close to not existing as any stuff could be. That’s how elusive it is. Where’s my proof? Are you kidding? This stuff cannot be proven to exist. That’s probably its only real property. Equations pass right through it. Now where’s my Nobel? Before we forget.
Just like gravity, it’s a name for something they don’t understand..................