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Black Holes Trigger Stars to Self-Destruct Scientists have long understood that supermassive black holes weighing millions or billions of suns can tear apart stars that come too close.The black hotels gravity pulls harder on the nearest part of the star，an imbalance that pulls the star apart over a period of minutes or hours，once it gets close enough. Scientists say this Uneven pulling is not the only hazard facing the star.The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within.Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon，France1,carried out computer simulations of the final moments of such an unfortunate stars life，as it veered towards a supermassive black hole. When the star gets close enough，the uneven forces flatten it into a pancake shape.Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart.But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur. The new simulations investigated the effects of shock waves in detail，and found that even when their effects are included，the conditions favor a nuclear explosion.There will be an explosion of the starit will be completely destroyed, Brassart says. Although the explosion obliterates the star，it saves some of the stars matter from being devoured by the black hole.The explosion is powerful enough to hurl much of the stars matter out of the black holes reach，he says. | 
