astroengine writes "Some of the supermassive black holes at the centers of galaxies have powerful jets blasting from their poles, and others have weak jets, but many don't have jets at all. Why is this the case? In new simulations carried out by astronomers at NASA and MIT, it would appear that the way in which the black hole spins relative to its accretion disk may be a contributing factor. Strangely enough, the results indicate that if the black hole rotates in the opposite direction to its accretion disk, the most powerful jets form. The region between the black hole event horizon and the accretion disk still baffles scientists, so these simulations are very speculative, but the results seem to match what radio astronomers are seeing in the cores of active galaxies. Perhaps it's time to fire up that event horizon telescope!"