often is the case – seriously misperceived (such
as a reflection on one’s window or windshield
being perceived as a bright object at a distance).
Nevertheless, the chart introduces several of the
most common descriptions of UFOs, together
with some of their possible identifications.
Observational Issues
Sightings are influenced by the conditions
under which they are observed. For example,
bright stars and planets may become UFOs due
to being watched from a moving car and thus
seeming to keep pace with it.
An important basic observation-related fact
is that neither an estimate of the presumed
craft’s distance from the viewer not its size or
speed can be made unless one of the factors is
known. With multiple unknowns, one is simply
engaging in the widest guessing. If the guess as
to one of the three factors is in error, the others
will be wrong accordingly.
The only way to objectively evaluate an object
or light in the sky is by first characterizing it
with (1) angular velocity (how fast it is moving
through the sky, measured in degrees per
second), (2) angular size (measured in degrees-
for example a full moon subtends and angle
of half a degree), and (3) angular position
(measured in degrees of altitude and azimuth).
Illusions
For our purposes here, we define illusion as a
deceptive but objectively existing image- that is,
something that can actually be seen (and photo-
graphed), such as a mirage. We distinguish
this from the mental image that is imaginary,
hallucinatory, or the like, understanding that
one can transform an objective image into
something quite different by mental action
(for example, one’s expectation may transform
a light into the perception of a shiny metallic
object).
Various common illusions need to be
understood. One can occur when the observer
stares at a bright light in the dark, whereupon
it may seem to dart about, zigzag, wobble, etc.
This can be caused by the natural, involuntary
jerking movements of the human eye and is
known as the autokinetic effect.
Another illusory effect includes the movement
and flashing of colors that are sometimes
ascribed to a bright UFO seen at night. Called
scintillation, it causes the “twinkling” of stars
due to atmospheric turbulence – or of planets
when our atmosphere is especially turbulent. It
may occur even on a clear night and can affect
a single celestial light. Indeed, scintillation
can affect any visible point of light. The effect
results from refraction (bending) of the different
wavelengths, producing (to the eye or camera)
the changing colors and motion.
An illusion of hovering can occur when, for
example, a slow-moving craft flies directly
toward or away from the observer. This gives
the impression that the “UFO” is remaining
motionless and thus “hovering.” In one case,
a New Hampshire UFO with colored lights
appeared to remain stationary for a minute
before it “moved away” from the observers “as
if sensing their approach.” It was, in fact, a well-
lit airplane, a DC-9, making its final approach
to an airport. In one instance a UFO-another
plane-was reported “hovering” in the distance
for some twenty minutes.
Size can also be illusory. For example, it is
a human tendency that the brighter a light
appears, the larger it is perceived.
The dramatic “disappearance” of a UFO may
occur for a variety of reasons. An aircraft may
shut off its bright lights or change the angle
at which the observer views it. As well, a star,
perhaps watched for a long time due to its
flashing colors, may be obscured suddenly by
moving clouds.
Many illusions occur in daytime as well. For
example, a UFO that appears to move against the
wind, and so supposedly cannot be a balloon,
mat be propelled by high-attitude winds that
can differ in direction from ground winds.
The UFO Impostors
Many things can go unidentified in the day or
night sky, particularly to untrained observers-
as most people are, even pilots make “relatively
poor witnesses”-no doubt because they are
trained fly airplanes, not identify a UFO under
unknown and perhaps unusual conditions. TheThe Modern RationalistJuly 2019