Fortean Picture Library
Most UFO reports turn out to have conventional explanations. Typically, IFO (identified flying object) sightings are of stars, planets, meteors, balloons, advertising planes, optical illusions, and hoaxes. Skeptics argue that the remainder of the reports could probably be explained if additional information were available. This argument sounds logical but is in fact demonstrably false.
Between 1952 and 1955 the Battelle Memorial Institute in Columbus, Ohio, a think tank that does classified analytical work for the U.S. government, studied a collection of UFO reports from Project Blue Book. The Institute established that the unexplained sightings were fundamentally different from both explained sightings and those sightings with insufficient information for evaluation. Moreover, the "unknowns" came from the best-qualified observers, the sightings were of longer duration, and the unknown objects seldom bore any resemblance to their conventional counterparts.