The Skeptics Society & Skeptic magazine

Black Holes are the ultimate death state of very massive stars. Collapsing under their own weight, the dead cores will curve spacetime so strongly that not even light can escape. Black holes emit no light and reflect no light. They are dark against a dark sky and effectively invisible. When two black holes move in orbit around each other, they churn up the spacetime around them, emanating waves in the fabric of space itself…