But that could finally change following the official release of information from the Pentagon about the mysterious aerial phenomena.
Based on clues from reported sightings, the typical UFO has a round shape, usually described as spherical or an orb, with a white or silver colour, often translucent.
It also has a size of between 3 and 13 feet (1 to 4 metres) and usually travels through the air at a height just below commercial passenger planes.
The Pentagon has also released a hotspot map that reveals the location of reported UFO sightings, including Japan and the Middle East.
Details about the typical UFO, based on reports between 1996 and 2023, were revealed in the document posted to the new website of the AARO, a dedicated UFO office under the Department of Defense, formed in July last year.
AARO discloses that most UFOs (28 per cent) have been sighted at altitudes of around 20,000 feet – just under commercial air traffic.
Around 10 per cent have been reported at just 5,000 feet – around eight times as tall as Seattle’s Space Needle and three times as tall as New York’s One World Tower.
In terms of shape, most of them (47 per cent) have been described as ‘orb’, ’round’ or ‘sphere’, while one per cent have been Tic Tac-shaped.
One of the most famous and unusual UFOs to date, spotted by the US Navy in 2004, was the floaty white oblong similar to the breath mint.
Other UFO shapes include rectangle, oval, triangle, disk, cylinder, square and even polygon, although 19 have had an ‘ambiguous’ shape.
Meanwhile, 16 per cent have been described as having lights, although in many cases this may have been due to their reflective qualities.
‘Thermal signatures’ include the emission of shortwave or medium-wave infrared light, which is invisible to the naked eye but can be picked up by special detectors.
In terms of velocity, it is generally ‘stationary to Mach 2’ – meaning the UFO will range from not moving at all to moving at two times the speed of sound, which is just over 1,500 miles per hour.
And it has ‘no thermal exhaust detected’, so the ones that move at considerable speeds may have other means of propulsion, albeit unknown.
UFO stands for ‘unidentified flying object’ and so the term doesn’t necessarily describe an object with an extraterrestrial origin.
Department of Defense, commonly known as the Pentagon, now refrains from using the term UFO at all.
This is largely because it is commonly associated with wind up conspiracy theories and paranoia (such as the ‘time traveler’ who claims an alien invasion will take place next year).
Instead, the Pentagon uses UAP – ‘unidentified aerial phenomenon’ – although in most places this has low usage and is yet to enter common parlance. AARO explains: ‘DoD considers unidentified anomalous phenomena (UAP) as sources of anomalous detections in one or more domain (i.e., airborne, seaborne, spaceborne, and/or transmedium).