Project Blue Book Special Report (second copy)

INTRODUCTION
In June, 1947, Kenneth Arnold, a Boise, Idaho, businessman and
private pilot, publicly reported the now-famous sighting of a chainlike
formation of disc-shaped objects near Mount Rainier, Washington. Result-
ing newspaper publicity of this incident caught the public interest, and,
shortly thereafter, a rash of reports of unidentified aerial objects spawned
the term "flying saucers". During the years since 1947, many reports of
unidentified aerial objects have been received by the Air Force from many
and diverse sources.
The unfortunate term "flying saucer", or "flying disc", because of
its widespread and indiscriminate use, requires definition. Many defini-
tions have been offered, one of the best being that originated by Dr. J.
Allen Hynek3 Director of the Emerson McMillin Observatory of The Ohio
State University, who has taken a scientific interest in the problem of
unidentified aerial objects since 1949. Dr. Hynek1 s definition of the term
is "any aerial phenomenon or sighting that remains unexplained to the
viewer at least long enough for him to write a report about it"\l). Dr. Hynek,
elaborating on his definition, says, "Each flying saucer, so defined, has
associated with it a probable lifetime. It wanders in the field of public in-
spection like an electron in a field of ions, until ' captured1 by an explana-
tion which puts an end to its existence as a 'flying saucer'"^).
This definition -would be applicable to any and all of the sightings
which remained unidentified throughout this study. However, the term
"flying saucers" shall be used hereafter in this report to mean a novel,
airborne phenomenon, a manifestation that is not a part of or readily ex-
plainable by the fund of scientific knowledge known to be possessed by the
Free World. This would include such items as natural phenomena that are
not yet completely understood, ps^cjioliigical phejiorne,na, or intruder air-
craft of a type that may be possessed by some source in large enough
numbers so that more than one independent mission may have been flown
and reported. Thus, these phenomena are of the type'which should have
been observed and reported more than once.
Since 1947, public interest in the subject of unidentified aerial objects
fluctuated more or less within reasonable limits until the summer of 1952,
when the frequency of reports of sightings reached a peak, possibly stimu-
lated by several'articles on the subject in leading popular magazines.
Early in 1952, the Air Force1 s cumulative study and analysis of
reported sightings indicated that the majority of reports could be accounted
for as misinterpretations of known objects (suchas meteors, balloons, or
aircraft), a few as the result of mild hysteria, and a very few as the result
of unfamiliar meteorological phenomena and light aberrations. However,
(1) Hynek, J. A., "Unusual Aerial Phenomena", Journal of the Optical Society of America, 43 (4),
pp 311-314, April, 1953.
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