So, our universe has a very odd descripancy: we have much more "regular" matter than antimatter. To briefly explain what that is, take the electron of regular matter. Now imagine the electron had instead a postive, rather than a negative, charge. That is a positron, one of the many antimatter particles we have discovered following Paul Dirac's unification of quantum mechanics and special relativity.
Now, why do we have more matter than antimatter? While, one important characteristic of antimatter is that is moves "backwards" in time, or rather it just flows the opposite way in time than our matter. My theory is that the missing antimatter that throws our ratio off is actually just all flowing backwards in time in a "reverse" universe, until it meets the Big Bang, where the antimatter does a U-turn and becomes regular matter. The same goes for regular matter, and then once it reaches the end of our universe (a Big Chill, most likely), that matter turns around and becomes antimatter. Â This is similar to a theory proposed to John Wheeler, but it only involved one single electron zipping through time, and today that theory has not been taken too seriously. My theory means we have a finite amount of matter (energy, equivalently under E=mc^2), so this theory doesn't contradict the Law of Conservation of Energy (very important, even though it seems trivial). This theory also helps explain why special relativity forbids us from going backwards in time, it just can't happen. Most importantly, it helps to explain where our missing antimatter from measurements is. This is also pretty neat, it's like we are a part of a big Feymann diagram reaction!
If you are in academia and can help me publish or get more attention to this theory/idea, please feel free to reach out. Thanks for reading!!