Figure 1
From: Quantum communications and quantum metrology in the spacetime of a rotating planet
Alice on Earth sends a photon (localised around the straight line) to Bob in the satellite. The photon experiences the effects of the curvature of spacetime along the whole path while propagating, which can be seen in the picture by the progressive flattening and redshifting of the Gaussian wavepacket. The final effect is a nonlocal and cumulative effect due to travel along the whole path.