that just won't work in so many ways
e.g. light is faster, so the timescale would be shorter.

To get a year delay you'd need an optical path a (heh) light year long. For six years, it'd have to (in effect) travel to Alpha Centauri and back.

Unless you want to posit a nearby group of atom-trapping physicists with some kind of slow-light holographic storage system and a tunable recurrence time. Has anybody seen such a thing near their ghost sightings? Should be easy to spot ... especially by the impressive blizzard of publications in PRL and Nature Physics appearing shortly thereafter.

Alternatively, I could nip downstairs to the Centre for Cold Matter's labs and try to see if there's an unexplained spectral presence.
(haberman is singing in the changes, Thu 3 Jul 2008, 12:56, Reply)