The E wrote:And as David Weber himself has said in this very thread, that is why most planets that have traffic control also have very strict rules about the use of impellers anywhere near them, including lethal responses if it looks like a ship intends to disobey orders to shut down its impellers.
Oh, I'm not really criticise the tech itself. I'm just feeling that any argument about the physics problems of c fractional velocity object detection and limitations is kind of silly and unnecessary given that the danger is enormous even without it.
But as for the orbital security...
Let's say you do the accelerating in question somewhere outside Jupiter orbit, at a time where earth is on the opposite side of Sun, and then hide it as part of a convoy and kill it's accel before they can be counted (or something. The books have several examples of ways gravitic sensors can be spoofed to miss strength/number of sources, so it's not impossible).
Basic orbital mechanics should enable anyone to create a collision course with a cork-screw orbital path so that it will hit from any direction you choose in 10 months or so...
How would anyone detect a dead multi-megaton freighter hulk travelling at 0.01c? It'll take it some time to reach it's target, but what is a year for a planet-killer?
In the end we must assume that:
If this technology existed, these sort of problems certainly would have been considered (you probably can't get rid of all the nerds, whatever you do) and a solution would have been found, or else there would be dead planets.
All-in-all, since the concepts of an anti-gravity civilization requires rather fundamental (to say the least) shifts in our understanding of both relativistic and quantum physics, we can probably assume that our discussions on it's limitations are rather pointless.
And the number of consequences any physics-breaking technology can have are huge, so why focus on the big ones. The smaller ones are usually much scarier, and funnier, in my experience.
How to destroy a spaceport/city/annoying commie-anarcho-capitalist-leftist-conservative?
See the fate of PNS Tepes...
There is the point where we simply have to activate our suspension of disbelief...