What does the term 'shadow' imply about light-bending around a black hole?

• A. A physical surface on the black hole.
• B. A bright ring of emission.
• C. The dark region where light cannot escape due to extreme bending and capture by the horizon.
• D. A region of space devoid of any light.

Answer: (C)

Light bending in strong gravity creates a dark patch in the black hole’s image because many light paths are captured by the horizon. As photons approach the hole, the curvature of spacetime can direct them into the event horizon, so they never reach your eye. The boundary of this dark region is set by photons that are on the verge of being captured—those that skim near the photon sphere can loop around the hole and may escape, producing the bright ring you sometimes see around the shadow. So the shadow isn’t a physical surface or a complete absence of light everywhere; it’s a deficit of photons from directions that would lead straight into the black hole.