This labeled diagram separates features that are often blended together: the event horizon is a boundary, the black-hole shadow is an apparent dark region, and the glowing accretion disk is matter outside the hole. The singularity is a prediction of classical general relativity, not something astronomers can directly observe.
The same hot gas disk looks narrower when you view it from the side. Use the angle slider, or drag across the 3D model to change your viewpoint. The central shadow and the event horizon are not identical objects.
Conceptual 3D geometry, not a photograph or general-relativistic ray-traced simulation. Gas turbulence, bright orbiting knots and differential rotational speed are compressed illustrative patterns, not predicted accretion rates or time. The gas colors, glowing light-bending guide and rotation are illustrative; real gravitational lensing is not ray-traced here: in physical ray-traced images, light from the far side can appear above and below the disk. The upper and lower arc guides in this 3D illustration do not calculate actual photon paths. The critical light-path scale is about 2.60 times the horizon radius for a non-rotating Schwarzschild black hole; an observed shadow depends on the emitting material. The optional camera glide only approaches the illustrative disk; it never crosses the event horizon or calculates a physically possible spacecraft trajectory. The disk is not to scale. NASA: Black Hole Anatomy and Goddard ray-traced visualization.
Event horizon is not a photographed surface. The size guide, when enabled, identifies its model radius inside the apparent shadow; it does not make the invisible horizon luminous.
The exact radii below apply to a non-rotating Schwarzschild black hole where stated. Real astrophysical black holes can spin, which changes the geometry.
| Feature | What it is | What an observer sees | Important distinction |
|---|---|---|---|
| Singularity | A breakdown point predicted by classical general relativity inside the hole. | Not directly observable. | Its true quantum-scale structure is unknown. |
| Event horizon | The causal boundary beyond which signals cannot return to the outside universe. | Not a glowing or solid surface. | For a Schwarzschild black hole, radius rs = 2GM/c². |
| Black-hole shadow | An apparent dark region produced by captured and strongly lensed light paths. | The central brightness depression seen in horizon-scale images. | The shadow appears larger than the event horizon itself. |
| Photon sphere / photon rings | The photon sphere is a region of unstable circular light orbits; photon rings are thin image features made by highly lensed light. | Nested, increasingly thin ring features in idealized images. | For a Schwarzschild hole, the photon-sphere radius is 1.5 rs; the observed ring is not the event horizon. |
| Accretion disk | Hot orbiting matter outside the black hole. | Bright radio, optical, UV, and X-ray emission depending on the system. | Not every black hole has a bright disk; the disk's inner edge depends on spin and flow physics. |
There is no single official four-part list. Introductory diagrams commonly label the event horizon, black-hole shadow, accretion disk, and singularity. More detailed diagrams may add the photon sphere or photon rings, a corona, and jets.
No. At the same distance, an object feels the same gravitational pull from a black hole as it would from any other object with the same mass. The extreme one-way behavior appears at the event horizon.
The EHT reconstructed radio emission around M87* and Sagittarius A*. The images show a bright ring surrounding a central black-hole shadow consistent with general relativity; they are not direct photographs of a solid event horizon or the singularity.
Real images (like the Event Horizon Telescope's) are blurry, radio-wavelength composites — this diagram exaggerates and labels features for clarity, the same "illustration, not photograph" distinction covered elsewhere on this site.
A black hole with nothing nearby to pull in has no accretion disk and emits no light at all — it's detected only through its gravity's effect on nearby stars.
See which stars can end their lives as stellar-mass black holes.
Separate observations, processed data, simulations, and artist concepts before interpreting a black-hole image.
Place stellar and supermassive black holes in the larger cosmic scale.
