-------preceding post snipped-------

The big question is "why does the wake turbulence descend?"
Is the air volume inside the vortices denser than surrounding air?
Probably not. So the descent is probably not due to gravitational
force.

------much snipped for brevity------

First of all, what this thread really proves is that it is not necessary for
a pilot to understand this well enough to explain it to a lay person, or
even to another pilot.

I think that the bigger question is: Why have so many people, who should
all know better, taken Mxsmanic's statement regarding the central downwash
portion of an aircraft's wake, which he extrapolated as applicable to the
motion of the entire wake, and simply accepted it as possibly disproving
what *all* of us have consistently observed.

I really don't think that Mxsmanic is an intentional troll, in the usual
sense--but, however inadvertently, he surely is damned good at it!

Peter