UFO or Unidentified Flying Object, according to Wikipedia, is an airborne object or optical phenomenon, detected visually or by radar, whose nature is not readily known. Dr. J. Allen Hynek, a late astronmoer, gives more detail definition about UFO.

“A UFO is the reported perception of an object or light seen in the sky or upon the land the appearance, trajectory, and general dynamic and luminescent behaviour of which do not suggest a logical, conventional explanation and which is not only mystifying to the original percipients but remains unidentified after close scrutiny of all available evidence by persons who are technically capable of making a common sense identification, if one is possible.”

Until today, the existence of UFO is still a mystery. Whether it’s real or just a big hoax, nobody ever knew. It is said that the first mysterious flying object appeared across Nort maerica US in 1896-97 (source). According to the newspaper, the ships were usually said to be a type of dirigible, and were usually differentiated from gliders or hot air balloons. Eventhough many investigators think the airship reports were hoaxes, a few ufologists, however, are convinced these airship sightings represent the first reliable UFO reports in history.

The year 1909 probably the busiest years for the UFO. There were several mystery airship appearance during that years in Britain (1909-1910), New Zealand, and US (1909-1910). In 1912-1913, the airship were seen again in Britain.

The war also brought some mystery. During the First World War there were mystery aircraft scares in South Africa, Canada, Great Britain and the USA. And then during World War II, a luminous balls that followed airplanes, called “foo-fighters” – a term based on an expression (”where there’s foo, there’s fire”) from Smokey Stover, a popular comic strip at the time – were reported by both Allied and Axis pilots. The funniest thing is, the Allied command thought that the foo-fighters were secret Germany weapons or surveillance devices. And vice versa, the Axis command also thought that they were American or British secret devices!

Several good sources for UFO-related material:

• http://www.ufo.it/english/index2.htm
• http://www.nuforc.org/ (National UFO Reporting Center)
• http://www.cufos.org/ (Center for UFO Studies)
• http://www.oregonuforeview.com/photos.html (UFO Photo Gallery)