Lesson · beginner · 5 min
What a Black Hole Shadow Means
Separate the event horizon from the larger shadow seen in Event Horizon Telescope images.
Learning goal
Distinguish the event horizon from the observed black-hole shadow.
Key idea
Light bends near a black hole. The dark central region in EHT images is a shadow shaped by photon orbits and the horizon — larger than the horizon itself. The bright ring is emission from hot plasma around the hole, distorted by gravity.