Cygnus X-1

Over three decades ago, Stephen Hawking placed, and eventually lost, a bet against the existence of a black hole in Cygnus X-1. Today, astronomers are confident the Cygnus X-1 system contains a black hole. In fact, a team of scientists has combined data from radio, optical, and X-ray telescopes including Chandra to determine the black hole's spin, mass, and distance more precisely than ever before. With these key pieces of information, the history of the black hole has been reconstructed. This new information gives astronomers strong clues about how the black hole was born, how much it weighed, and how fast it was spinning. This is important because scientists still would like to know much more about the birth of black holes.

Video credit: Optical: DSS; Illustration: NASA/CXC/M.Weiss

Note: For more information, see Cygnus X-1: NASA's Chandra Adds to Black Hole Birth Announcement.