>When 'liewitnesses' claim sudden changes in direction, they are using their
own
>stationary reference. Anyone experienced in air operations of tactical
military
>or other high performance aerobatic aircraft know that this perception is
false,
>because the people are ignoring changes in distance. To the observer, a
vehicle
>travelling across one's field of view will seem to come to a rapid stop and
>hover, then zoom off in another direction, when in actuality they are
conducting
>a turn where the midpoint of the turn is when the plane is either moving
toward
>or away from the observer, so it just seems to hover. Whenever I hear of a
UFO
>report that includes 'rapid changes in direction', I know what is actually
going
>on, and that the eyewitness is ignorant of flight dynamics, and lacks an
ability
>to think in three dimensions. Note that people have poor depth perception at
>long range.
Quite true in a great many cases, but there is a body of close-range reports and other, videotaped reports, that indicate that we might be dealing with a truly exotic propulsion system. There have been a handful of mass-sighting reports when the object under question was seen by many only at certain angles; to all intents and purposes, it was "invisible" to other witnesses who saw the object reappear shortly after.
Mac Tonnies