Another point about Nightshifts questions/statements. There is nothing to say that somewhere there are particles that travel faster than light. (eg the much discussed Tachyon) However for normal Baryon matter (electrons, neutrons and protons etc) it would take infinite energy to accellerate to the speed of light. As the velocity increases, its mass would increase, requiring more energy to accellerated it, requiring more energy to accellerate it, increasing its mass ..... ad infinitum. Therefore any Baryon object accellerated to the speed of light would gain infinite mass requiring infinite energy to keep it accellerating.
The same holds true for the theorized Tachyon. It would require infinite evergy to slow it down to the speed of light.
This is all according to theory of course
Does this apply to dark matter? Who knows. We can't even agree on what it is.