Some Emerging Possibilities For Space Propulsion

Some Emerging Possibilities For Space Propulsion
nasa.gov

They spend a lot of time discussing quantum vacuum energy, but the one short note about its "propulsion implications" includes the comment that "Those particular gravity theories are still up for debate." That's perhaps generous: quantum gravity isn't far from my field, and I've never heard of this take on the origin of gravity and inertia.

I'm also rather puzzled by the quote "Although gravity’s effects on electromagnetism and spacetime have been observed, the reverse possibility, of using electromagnetism to affect gravity, inertia, or spacetime is unknown." That's really not at all true. Our models of gravity all include very well-defined effects of electromagnetism on spacetime: the energy density in those fields causes space to curve, just like any other form of mass or energy. Hypothesizing anything else would require fundamental changes to the theory. That's entirely possible! But it's misleading to characterize the current state of affairs as having an unfilled gap like this.

So yeah. I'd love a good spacedrive as much as the next guy. But this article doesn't do much to make me optimistic about it.

People always use causality to argue against FTL, but then readily acknowledge that wormholes or Albicurie might allow it. I'm not getting that disconnect?

I remember reading about it somewhere, but I can never find it again.

No offense intended to you, but I feel this is a disastrously negative attitude to have. Except where morals dictate otherwise (which are outside the scope of science anyway) nothing is banned from exploration. Suggesting otherwise implies that we know all there is to know about a subject; to me, this is analogous to willful ignorance. Science is dedicated to removing ignorance, not enforcing it.