From what I've seen, the possibility of matter-antimatter to mutually repel each other is ruled out, but, can the following hypothesis be ruled out? : Gravity --> A property of matter & antimatter (not of mass) Matter gravity --> A "force" that pulls "everything" Antimatter gravity --> A "force" that repels "everything" If this is not ruled out, then: In the beggining of the universe, a gravitational effect like this, would make the concetration of matter higher at the center of the tiny universe "globe", while antimatter would mainly concetrate far from it. Therefore there would be 3 types of reactions : Energy ---> Matter + Antimatter Matter + Antimatter ---> Energy Mass ---> Energy Since more matter than antimatter would be at the center (hotter area), the matter mass would disappear at higher rates than the antimatter mass and we would therefore have more antimatter than matter as a total. As matter kept decaying at higher rates into energy due to its gravitational effect, the "repel forces" of the antimatter gravity were becoming more dominant, pushing the universe to expand. And so, the current situation would be: 1) Antimatter is more than matter. 2) Matter continous to decay into energy due to its gravitational effect, and therefore antimatter keeps becoming increasingly dominant 3) We can't detect the antimatter because of its gravitational effect that makes it spread through the entire universe in the form of single individual particles 4) Dark Energy probably is the gravitational effect of this antimatter What do you think of it?