tlb wrote:Just to make clear, here is a summary of my understanding.
An active sensor is any device that sends out a signal and reads the echo: so LIDAR or RADAR, etc.
A passive sensor is a device that reads the signals generated by (or at) the object of interest: so gravitics from wedges or transitions or heat signature, etc.
We do not know of any active FTL sensor. We expect that the spider drive creates vibrations in that Alpha wall (so FTL).
The spike when a spider drive starts up might be an electromagnetic power surge, which would be light speed.
Though there are deliberate FTL transmissions - FTL coms/fire control. It's just, as far as we know, there's nothing that those can echo back off of - so they can't be used as an active sensor.
(Though a few folks here have speculated that it's possible that a spider tractor's grab on the Alpha wall might cause a 'hard spot' that would distort or even reflect the grav ripples of FTL coms as they tried to pass through the point a spider tractor was currently grabbing -- potentially allowing FTL coms to be turned into some kind of spider drive detector. But that's purely forum speculation)