# Interaction of external light or matter and an Alcubierre warp bubble

For a hypothetical vehicle traveling in an Alcubierre bubble at faster-than-light (FTL) velocities, what would happen when the leading edge of the bubble encounters incident particles or photons?

Let's say either a stationary particle of matter, a photon traveling in the opposite direction to the vehicle, or a photon traveling in the same direction as the vehicle. Would they ultimately end up inside the bubble to encounter the vehicle traveling within?

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This ArXiv pre-print by Brendan McMonigal actually answers this problem! He considers particles of velocities ranging from $-c$ to $+c$ (the sign denoting direction relative to the bubble, I believe) and finds that, for the most part, the particles would indeed enter & exit the bubble (receiving a velocity boost) without much trouble.