The Reissner–Nordström black hole is a solution to Einstein’s field equations that describes a charged, non-rotating black hole. Unlike the Schwarzschild black hole (which has no charge or spin), this type of black hole carries electric charge, making it an important model for exploring how electromagnetism interacts with gravity.
This solution introduces two key features:
- Outer and inner horizons: Instead of a single event horizon like the Schwarzschild black hole, a Reissner–Nordström black hole has two—an outer event horizon and an inner Cauchy horizon.
- Singularity shielding: The electric charge influences the spacetime structure, altering the way gravity behaves near the singularity.
In theory, if the charge becomes too large relative to the mass, the horizons disappear, exposing the singularity—leading to what’s called a naked singularity, which violates the cosmic censorship conjecture.
While such highly charged black holes are unlikely to exist in nature—since astrophysical objects tend to neutralize quickly—the Reissner–Nordström solution is important for understanding how black holes behave when influenced by electromagnetic forces as well as gravity.