A supermassive black hole 9 billion light-years away appears to have a companion black hole orbiting around it. As the orbit shrinks, the pair gets closer to merging. Supermassive black holes millions to billions of times the mass of our Sun lie at the heart of most galaxies, and astronomers are eager to know how … Continue reading Astronomers Find Two Supermassive Black Holes Spiraling Toward a Cataclysmic Collision