How a Whirlpool in a Cup Becomes a Black Hole Bomb
When liquid is swirled in a cup, a vortex with an empty center forms. In this empty core, waves find a trap: bouncing off the walls, they siphon energy from the vortex and grow like a flame along a fuse — each wave stronger than the last, until a surge breaks loose.
Astrophysicists have described the same chain reaction around black holes.