A Planck star is a hypothetical ultra-dense object proposed as an alternative to the classical black hole singularity. Instead of collapsing into a point of infinite density, the core of a black hole could reach a minimum possible size due to quantum gravity effects.
General relativity predicts singularities—points of zero volume and infinite density—at the center of black holes. However, quantum mechanics suggests space-time should be "quantized" at the smallest scales, preventing true singularities.
Formation of Planck star[]
- As a massive star collapses into a black hole, space-time warps around it.
- Normally, this collapse continues indefinitely, forming a singularity. Quantum gravity could prevent this by creating an extreme pressure at the Planck scale (~10−35 m).
- This pressure could cause a "bounce" effect inside the black hole, stopping complete collapse. Thus, a Planck star could be an ultra-compressed, stable remnant inside black holes.
Planck star evaporation[]
- Black holes emit Hawking radiation and slowly lose mass. This process takes trillions of years.
- But if a Planck Star exists, its extreme space-time warping could speed up this process.
- Eventually, the black hole could shrink enough to reveal the Planck star before completely evaporating.
- If true, this means black holes don’t "die" into singularities—they shrink into Planck stars before disappearing.
Observing Planck Star remnants could confirm quantum gravity theories.