Response to the Comment on "Observing a wormhole"

Abstract

In the Comment written by Krasnikov \cite{Krasnikov:2019mrd} on our recent paper \cite{Dai:2019mse}, the author argues that a spherically symmetric perturbation coming from a massive object located on the other side of the wormhole would just add up to the total mass of the central object, and is therefore useless as an indicator of the wormhole presence. We point out that our Eq.~(37) represents an {\it acceleration variation} in the motion of the star S2 due to an elliptic (and thus non-spherically symmetric) orbit of the star on the other side perturbing the metric. This time-dependent acceleration variation is in principle distinguishable from the original acceleration coming from the central object. We also point out that the author is trying to apply Birkhoff's theorem in a setup where it cannot be applied in a straightforward way.