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Using the supersharp radio “vision” of the National Science Foundation’s Very Long Baseline Array, astronomers have made the first detection of orbital motion in a pair of supermassive black holes in a galaxy some 750 million light-years from Earth. The two black holes, with a combined mass 15 billion times that of the sun, are likely separated by only about 24 light-years, extremely close for such a system.
Supermassive black holes, with millions or billions of times the mass of the sun, reside at the cores of most galaxies. The presence of two such monsters at the center of a single galaxy means that the galaxy merged with another some time in the past. In such cases, the two black holes themselves may eventually merge in an event that would produce gravitational waves that ripple across the universe.Image credit: Josh Valenzuela/University of New Mexico
