What does spacetime curvature imply about motion near a black hole?

• A. Objects and light travel in straight lines in flat spacetime.
• B. Gravity curves spacetime so that matter and light follow geodesics, producing redshift, lensing, and time dilation.
• C. Only light is affected, not massive particles.
• D. Curvature only affects distant objects far from the horizon.

Answer: (B)

General relativity says mass-energy curves spacetime, and free-falling objects follow the straightest possible paths in that curved geometry, called geodesics. Near a black hole, the curvature is extreme, so what looks like a straight path in ordinary space becomes a curved trajectory when described from afar. Both massive particles and light thus bend their paths not because of a force acting sideways, but because their natural motion is dictated by the curved spacetime around the hole. This curvature leads to three observable effects: gravitational redshift, where light climbing out of the deep gravitational well loses energy and shifts to longer wavelengths; gravitational lensing, where light’s path is bent by the mass, producing distorted or multiple images; and gravitational time dilation, where clocks closer to the black hole tick more slowly relative to distant clocks. So the motion near a black hole is governed by spacetime geometry that guides all objects along geodesics, with these hallmark consequences.