This might sound stupid but so does everything else to me. Einsteins theory shows that something with 0 mass could in fact have motion and be there as a form of energy even if not accountable through a perception of measurement. 95% of it is completly undetectable or unknown where it resides or what happens to it. If outter space was that 0 mass but a form of energy in motion, the missing 95% of measureable energy of matter. Wouldnt it be possible that earth is not rotating...but everything outside of earth- measureable or not, like space the sun,planets and stars and so forth is revolving around the earth. As in the earth is the center of the universe. When you are in space you might sit there and see the earth appear to be rotating. But with the theory that gives insight that 0 mass can in fact have motion as a form of energy. Space has 0 mass and could resemble an "ocean" and be the energy,while earth is the bearing of stillness or solidarity and all other matter out there is just objects stuck in that current of energy that space enables matter to travel through.