Empty it was, to all intents and purposes, until Dark Matter came along. Hinting at itself through lensing techniques and laying claim to a vast percentage of the Universe, but refusing to reveal its true nature, you'll find through Google that Dark Matter wasn't discovered by anyone, it's "purely theoretical." Unlike Heisenberg's Uncertainty Principle, Planck's Constant, Bohr's Atom and Einstein's Relativity, Dark Matter is an entity in its own right that not only refuses to be identified, but refuses to allow anyone to claim its identity, either.
All you need to do, if you're a scientist, is meditate. Seriously meditate. I mean, what harm can it do, to give yourself some quiet time away from the damn figures and drift into the landscape of your sub-subconscious mind? You have the keys, the Universe gave them to you. All the necessary tools are there at your disposal. You'll need the math to make sense of what you find out there. But relying on formulas to point the way is like looking for water with a compass.