Worse, it has deleterious effects on the spacetime inside the bubble too. The leading edge of the bubble has exactly the same curvature as a white hole, and the

Worse, it has deleterious effects on the spacetime inside the bubble too. The leading edge of the bubble has exactly the same curvature as a white hole, and the back edge is exactly like a black hole. The result is a beam of Hawking radiation between them. Expect temperatures on the order of 10³⁵K if you manage to stabilize the bubble, but note that this amount of radiation is much more than enough on its own to destabilize it. <https://en.wikipedia.org/wiki/Alcubierre_drive#Survivability_inside_the_bubble https://en.wikipedia.org/wiki/Alcubierre_drive#Survivability...> So not only do you need “exotic” matter with negative mass to bend spacetime into a warp bubble, the bubble itself creates so much radiation that spacetime is flattened back out again.