Physical concept · Astrophysics
The Event Horizon
Cosmology & UniverseEstablished Science
Definition
The boundary around a black hole beyond which nothing, not even light, can escape.
Scientific overview
The event horizon is not a physical surface but a point of no return: once matter or light crosses it, it cannot come back out. The Event Horizon Telescope imaged the shadow cast by this boundary around the black holes in M87 and the Milky Way.
Rests on
Related discoveries & objects
Measured by
Related topics
Knowledge connections
- Related toThe Schwarzschild Radius
- Related toGravitational Singularity
- Related toBlack Hole
- Related toSupermassive Black Hole
- Depends onGeneral Relativity
- Related toThe First Image of a Black Hole
- Measured byEvent Horizon Telescope (EHT)
- Related toM87*
- Related toSagittarius A*
- Related toGravitational Singularity
- Related toAccretion Disk
- Related toThe Schwarzschild Radius
- Required byBlack Hole
- Required bySupermassive Black Hole
- Associated withThe Ergosphere
- Associated withThe Photon Sphere
- Associated withThe No-Hair Theorem
- Associated withFrame-Dragging
- Associated withGravitational Redshift
Sources & references
The primary and reference sources this topic draws on.
- Event Horizon TelescopeEvent Horizon Telescope Collaboration
Horizon-scale images of supermassive black holes (M87*, Sagittarius A*).
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.