Powerful relativistic jets are observed in certain AGN, in particular blazars and radio galaxies.  Launched magneto-centrifugally from the environs of supermassive black holes, they accelerate while being collimated, and dissipate to accelerate particles and emit non-thermal radiation very efficiently.  Interferometric observations of nearby radio galaxies like M87 trace the jet collimation process all the way to the BH crescent image.  Blazars occasionally produce remarkably rapid and luminous gamma-ray flares.  Numerical simulations provide clues on the 3D structure of jets and their stability.  Yet, many mysteries of relativistic jets remain to be solved.

Sponsored by the McDonnell Center for the Space Sciences.