According to quantum theory, particles appear and disappear all the time. If they could be made to not disappear, that would be a practical energy source. That is probably what happened on a large scale during big bang. Such large scales of vacuum energy would bud off to form a separate universe, not damaging anything in this universe or any other preexisting universe. Vacuum energy could rescue the Universe from thermodynamic death, and creating new universes would create lots of new space! Maybe travel betwen universes can be achieved by wormholes. The Casimir effect is probably generated by a deficiency of vacuum energy caused by materials blocking the way for the energy. The workforce should test if graphene can generate a Casimir effect. Some blasted wikians delete all information about the Casimir effect from their article about graphene!