Here is the experience:
A photon P travels from X to Y through tube drilled inside the earth from the North Pole to the South Pole. A photon Q travels from A to B, which is the exact same segment translated outside the gravity pull of the earth.
Would the photon P take more time to reach its destination than the photon Q? Said otherwise, does the curvature of space generated by the earth's gravity makes the distance longer?
