Energy shifts of photons crossing an Alcubierre warp drive
We study the energy shifts of light propagating through an incoming Alcubierre warpdrive spacetime by numerically integrating the null geodesic equations derived from the warpdrive metric. We find that from the perspective of a distant observer in a co-moving reference frame with respect to the warpdrive, light passing through the Alcubierre warpdrive experiences an overall blueshift whose magnitude depends on the photon's impact parameter and the warp drive's velocity. The maximum net blueshift occurs at an impact parameter b ~ 3.46 − 0.098v with a maximum that scales as ~ 1+v. Thus, greater net blueshifts result from interacting with faster warpdrives, with the maximum blueshift occurring at smaller impact parameters.