[suilusargaino]

So while we are talking about inertia:

I will define a "warp drive" as any mechanism that accelerates a body by warping space/time around it, rather than by applying a force to the body and an equal and opposite force to some other bodies (which will accellerate in the opposite direction).

If such a drive is possible in principle it seems to me that the Law of Conservation of Momentum goes out of the window, at least for the bits of space/time where the warp drive has been working.

As evidence, consider a warp driven spacecraft operating somewhere near Earth. It fires up its warp drive and 2 hours later is say 1.8 light hours from Earth (we'll leave faster than light travel out of the picture for now). The centre of mass of the Earth/spacecraft system has now moved, since part of that system has moved 2 light hours, without a balancing movement of any other mass in the opposite direction.

How does this fit in with conservation of momentum?

Or doesn't it?