Green Flag. Watch the Scratch Cats being sucked into the Black Hole until they disappear at the Event Horizon. What is a Black Hole? (by Tutor-42) When stars run out of fuel to burn, they collapse under their own gravity. If the stars are large enough they collapse to be so dense with such strong gravitational forces that not even light can escape from them. The boundary where light cannot escape because of gravity is called the "event horizon". There is a Wikipedia definition of a Black Hole in the project Notes and Credits.
