U - Unidentified
F - Flying
O - Object
A UFO is any moving object spotted in the sky that cannot be identified by the observer. However, the term’s meaning has shifted since it was first used in the 1950s. Today, many people equate the term UFO with the sighting of an alleged alien spacecraft. Indeed, the term has become so synonymous with the idea of extraterrestrial visitation that the US government reclassified unidentified sightings as unidentified aerial phenomena (UAP) to avoid the association. -Richard Sheposh, Salem Press Encyclopedia of Science
Although many UFOs remain unidentified, we can't conclude that any or all of them are the workings of extraterrestrials. After all, the most recent UFO sighting to make headlines was later disclosed as being a spy balloon. You can read more about that specific encounter HERE. But with all the uncertainty of what's actually seen in the sky, one of the ways we can learn more is from the pilots who spot them first. Click Here for an article about a former Navy pilot making a group to do just that.
Ancient civilizations relied on a knowledge of the sky for their survival, as the movement of the sun, moon, and stars told them when to plant and harvest crops. Any celestial object that was out of the ordinary would surely have been noticed, although observers were far more likely to consider it a divine omen or harbinger of doom. Some accounts from ancient Egypt tell of “stars” falling to earth and defeating the pharaoh’s enemies, or of talking “flying disks,” but these are likely to be exaggerations from the time or possibly modern hoaxes. A fourth-century CE Roman text called the Book of Prodigies features historical accounts of strange objects burning through the sky and the sighting of mysterious celestial figures. However, the book was written centuries after the sightings allegedly occurred and the author could easily be referring to meteors or other common astronomical events.
In 1561, residents of the German city of Nuremberg reported witnessing a sky full of strange flying cylinders and globes that seemed to them like a celestial battle. The event was recorded by a Nuremberg printer on a broadsheet illustration. Modern experts dismiss any extraterrestrial involvement, saying the sightings could have been an astronomical event known as a sun dog. This occurs when sunlight is reflected by ice crystals in the atmosphere, giving the appearance of multiple suns in the sky.
During the nineteenth century, reports of lights in the sky or strange flying objects increased across the globe (though this perceived increase is likely in part simply due to better documentation). For example, in 1878, a farmer near Dallas, Texas, reported seeing a circular object in the sky. He referred to the object’s shape as a “large saucer.” In 1896 and 1897, residents across the United States reported seeing mysterious airships in the skies. However, none of these reports were considered to be of alien origin. The Texas farmer likely saw a hot air balloon, while experts believed the airship sightings were just inventors testing out a new technology. It was only near the start of the twentieth century that the idea of extraterrestrials was attached to the phenomena of mysterious atmospheric sightings. --Richard Sheposh, Salem Press Encyclopedia of Science
For further involvement in UFOs and the like, look at these articles:
