Light from within the shadow: what if it's not a black hole?

For the first time, researchers ran a full 3D magnetohydrodynamic simulation of accretion onto a compact object with no event horizon — and the result looks nearly indistinguishable from a black hole.

The team modeled JMN-1 (Joshi–Malafarina–Narayan) spacetime — a theoretical black hole mimicker arising from gravitational collapse with anisotropic pressure in general relativity. It has a central singularity but no event horizon, meaning light and information can escape outward.

The simulation produced a stable magnetically arrested disk (MAD). For M87* parameters, the accretion rate was ~3.0×10⁻⁶ Eddington — identical to black hole models. Synthetic 230 GHz images are broadly consistent with Event Horizon Telescope observations.

But there's a key difference: detectable brightness appears inside the JMN-1 shadow. This emission originates near the central singularity — a region that would be hidden behind the event horizon in a true black hole. Current instruments can't resolve it, but next-generation radio interferometers should be able to measure this signal and directly test the black hole paradigm.