KnowraTachyonLinked fromLinked fromThe 4 pages that link to Tachyon, each with the reason it gives.All 4Compared with 4Speed of lightCompared with: It is a speculative exception to the usual subluminal-or-light-speed particle picture.Light coneCompared with: Its proposed motion lies outside ordinary light cones and conflicts with standard causal order.Wigner classificationCompared with: Tachyonic representations differ from the usual positive-energy particle classes.Massless particleCompared with: Tachyons are not ordinary zero-mass particles and do not provide another established massless particle type.