The ageing problem of twins in Reissner–Nordström spacetime

In this paper, we explore the effect of gravity on the flow of proper time near static spherically symmetric black hole possessing an electric charge. We use the Reissner–Nordström metric. In the first case, the traveling twin travels away from the black hole and in the second it travels toward it. We then compare it with the case of relativistic kinematics where the static twin ages faster than the traveling twin.