What are our current predictions, if any, about the properties of tachyons? All I know is that their mass is equal to a complex number and that they speed up as they lose energy. I also heard that they thought neutrinos were tachyons until they fixed the loose cable at the OPERA. Have we predicted antitachyons? Could the beginning of tachyons themselves in the early universe have caused minor causality "ripples" in causality and been the reason for quantum indeterminacy? Do they possibly decay? How can they be detected?