Goksel Daylan Esmer

A black hole is like a whirlpool in a river: anything that falls in can never escape. But it also has an outer zone, the ergosphere, where space itself moves faster than light and drags any object along. Usually, the size of this zone is tightly linked to the hole's mass and spin rate.

Normally, by rapidly oscillating a mirror in a vacuum, you can conjure real particles from nothing: this is the dynamical Casimir effect. But near a black hole, things are different. The spacetime curvature itself stifles any attempt to create something.