The idea of tachyons (however unlikely their existence) is fascinating. Do you have any references that describe how they might explain the things you mention?

@Coffeo Way over my head but quantum entanglement because they could form the faster than light link between the particles. We don't have a mechanism to explain the expansion of the universe and we also don't have an antiparticle for the graviton which could could carry a repulsive force. If we had a whole new family of particles most of the antimatter could have ended on their side of the divide to maintain symetrey. If something moves at "infinite speed" it could be anywhere or everywhere when viewed from our side so we would need a new level of correspondence. It we view time as a 4th spacial dimension we could also view the tachydon field as a 5th spatial dimension that overlaps ours everywhere at once. Also I misspoke it would better explain dark energy not dark matter

@Buttercup I've always liked the idea of tachyons, but there are also lots of problems with the idea. It would really shake things up if their existence was demonstrated!

@Coffeo Yup, things get real crazy real quick.