The Galactic Core refers to the dense, star-cloud at the center of the galaxy. It is approximately 7000 light years in diameter and its nucleus is nearly 30,000 light years from Known Space. It was discovered by the Puppeteers to be undergoing a cataclysmic explosion, caused by a chain reaction of supernovae, sending out waves of deadly radiation that will engulf Known Space in approximately 20,000 years.