A boiling kettle on the stove eventually boils dry — and so, according to the classical picture, a black hole should gradually vanish in a hiss of radiation. But what if you add a special ingredient to the kettle? In a new study, physicists added a scalar field to the black hole equations — something like an omnipresent background that slightly changes the rules of the game.

It turns out that this additive acts like a regulator on the flame under the kettle. As the hole loses mass, its surface gravity (a measure of how strongly it pulls) decreases on its own. Hawking radiation, which usually heats up the surroundings, becomes colder and colder.

Calculations show that evaporation does not go to completion: the hole stops halfway, turning into a stable cold remnant — tiny but massive.

The most interesting part is the fate of information. It was usually thought that everything falling into a hole gets irreversibly mixed and leaks away with the radiation. Here, since the radiation flux dries up, the quantum entanglement between the hole and the emitted particles stops growing. Information is not erased but locked inside the cooled remnant, like a letter in a safe that is never opened again. This changes the famous Page curve — the graph describing how information returns from the hole — and does so without any discontinuities or catastrophes at the event horizon.