#50YearsAgoToday #Blackrock debuted in @dc.com #ActionComics #458 when #UnitedBroadcastingCompany #RAndDDirector #DrPeterSilverstone sought to challenge #GalaxyBroadcasting’s #Superman #eyeballGarneringCoverageSuccess by inventing via #RadioAndTVWaves #UBC’s own #SuperPoweredRevenueGeneratingMascot