▁Max well ' s ▁equations ▁are ▁invariant ▁under ▁a ▁much ▁wider ▁group ▁of ▁transformation ▁than ▁the ▁Lor ent z - group , ▁i . e ., ▁the ▁spher ical ▁wave ▁transformations , ▁being ▁a ▁form ▁of ▁conform al ▁transformations . ▁Under ▁those ▁transformations ▁the ▁equations ▁preserve ▁their ▁form ▁for ▁some ▁types ▁of ▁acceler ated ▁mot ions . ▁A ▁general ▁cov ari ant ▁form ulation ▁of ▁elect rod ynam ics ▁in ▁M ink owski ▁space ▁was ▁eventually ▁given ▁by ▁Friedrich ▁K ott ler ▁( 1 9 1 2 ), ▁where by ▁his ▁form ulation ▁is ▁also ▁valid ▁for ▁general ▁relativ ity . ▁Conc ern ing ▁the ▁further ▁development ▁of ▁the ▁description ▁of ▁acceler ated ▁motion ▁in ▁special ▁relativ ity , ▁the ▁works ▁by ▁L ange vin ▁and ▁others ▁for ▁rot ating ▁frames ▁( B orn ▁coordinates ), ▁and ▁by ▁Wolfgang ▁R ind ler ▁and ▁others ▁for ▁uniform ▁acceler ated ▁frames ▁( R ind ler ▁coordinates ) ▁must ▁be ▁mentioned . ▁ ▁R ig id ▁bodies ▁and ▁Ehren fest ▁par ado x ▁Ein stein ▁( 1 9 0 7 b ) ▁discussed ▁the ▁question ▁of ▁whether , ▁in ▁rig id ▁bodies , ▁as ▁well ▁as ▁in ▁all ▁other ▁cases , ▁the ▁velocity ▁of ▁information ▁can ▁exceed ▁the ▁speed ▁of ▁light , ▁and ▁explained ▁that ▁information ▁could ▁be ▁transm itted ▁under ▁these ▁circumstances ▁into ▁the ▁past , ▁thus ▁caus ality ▁would ▁be ▁viol ated . ▁Since ▁this ▁contra ven es ▁rad ically ▁against ▁every ▁experience , ▁super l um inal ▁veloc ities ▁are ▁thought ▁impossible .