By Ron Cowen
More evidence has emerged that supermassive black holes wield influence far beyond the grasp of their gravity.
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Five years ago, astronomers discovered that the core stars of a galaxy always weigh about 500 times as much as the galaxy’s supermassive black hole (SN: 1/22/05, p. 56: Available to subscribers at The Hole Story). That correlation seemed astonishing because a black hole’s pull extends less than a light-year from the galactic core, whereas the stars lie up to 20,000 times that distance.