[lovegoblin]

> The Alcubierre drive “beats” the speed of light

The Alcubierre drive is only a thought experiment that requires "exotic matter" (aka fairy dust) to work.

[baja_blast]

Papers have been published that have found ways to create warp drives without the need for exotic matter: https://arxiv.org/pdf/2006.07125.pdf

[xondono]

I know, I was making reference to this

> They are only theoretically possible if you allow for negative mass and energy--not an engineering problem so much as a "need to find exotic matter"

Basically people ran the EFE "backwards" to see what matter distribution makes the wanted curvature. You get either negative mass-energy or the bubble doesn't travel ftl iirc.