Since relativity theory requires that the value of c be the same for all observed physical processes regardless of relative velocity, it seems reasonable to hypothesize that matter that has no electromagnetic interaction with the rest of the universe may be accelerated to arbitrarily high velocities. Examples of such matter are neutrons and neutron stars, and hypothetical causes of superlight speeds might be the gravitational force exerted by a supermassive black hole. Is there anything about relativity theory that is inconsistent with this hypothesis? Testing it would probably be difficult, since all pertinent matter would necessarily be "dark". I presume the prevailing assumption is that relativity theory applies to all matter, but if that assumption were lifted for eletrically neutral particles, would it allow for a self-consistent mathematical model of black hole merger?