Define 'small' black holes. Define "Big" black holes.
THere is empirical data to show that there is a black hole in the center of the Galaxy. For that matter, there is a black hole at the center of every galaxy that the looked at for finding empirical evidence of a black hole. The one in the center of Milky way has the equivilant of nearly 4 million suns. THis is dwarfed by the black hole in the center of andromeda, which is about the mass of 140 millions stars. In a couple of billion years, when the Andromeda galaxy and the milky way 'collide', this should make for interesting disruptions as it is likely the milky way black hole will probably be captured and absorbed by the Andromeda black hole.
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