Unidentified Flying Objects

UFO's in general

UFO is short for "unidentified flying object", and not "extraterrestrial spacecraft", despite what many people seem to think. A better name might be "unidentified aerial phenomenon" (UAP), but "UFO" has stuck. I've also seen "unidentified aerial object" (UAO) and the U as "unconventional" or "unexplained". There is also an underwater version: USO, "unidentified submerged object".

Here is a UFO that I (lpetrich) once saw. I was traveling by airplane from Newark NJ to Ithaca NY in the winter, and I saw on the clouds a whitish spot that looked like a reflection off of a glass or clear-plastic pane. But there was no such pane in evidence, and my location was an unlikely one for such a pane. It would have to be huge. The spot sometimes flickered, but usually stayed constant in brightness. An extraterrestrial spacecraft following my plane? I decided that the clouds below my plane had an odd property: they had specular reflection in addition to diffuse reflection. I later found out that this was due to ice crystals in the clouds getting oriented as they fell. They have hexagonal symmetry, allowing them to have different optical properties in the horizontal and vertical directions. Others have seen this effect, and photographed it, and it is called a "subsun".

The term UFO was introduced by the United States Air Force as an alternative to "flying saucer", a rather goofy-sounding name. The USAF had investigated UFO's for two decades because of the possibility that some of them might be secret Russian airplanes or spy balloons.

The large majority of UFO's that have been investigated in detail have turned out to be known phenomena, though sometimes odd variations of them. Identified ones are sometimes called IFO's, Identified Flying Objects. Identification studies of UFOs - Wikipedia lists numerous identifications.

The planet Venus has been reported as a UFO numerous times, for instance. However, there are poorly-understood phenomena that some people have observed, like ball lightning. These may almost be called "real UFO's", but these are more likely odd natural phenomena than extraterrestrial spacecraft.

There are also nightmares, hallucinations, fantasies, and outright hoaxes. UFO skeptic Philip Klass once conceded that

I never encountered a single hoaxer during my entire 10 years with GE. And in my first 14 years at Av Week, up until the time I began investigating UFO reports, I encountered only one spinner of tall tales. So, believe it or not, when I first began looking at UFO reports, I naturally assumed that the witnesses were probably just honestly describing what they believed they had seen. But I quickly learned that I was too trusting.
(Phil Klass Interview). That's the General Electric corporation and the magazine Aviation Week and Space Technology, which Philip Klass had long written for. Many seemingly high-quality pictures and videos of extraterrestrial spacecraft have various features that suggest fakery.

UFO's have been classified in various ways. UFOlogist Dr. J. Allen Hynek has helpfully worked out a classification of UFO sightings, and various other authors have extended it (Close encounter - Wikipedia).

My UFO was a daylight disk that I decided was an IFO.

In recent years, we have been seeing what may be called the twilight of the UFO's: TWILIGHT OF THE GULLIBLE | More Intelligent Life. The proliferation of smartphones and digital cameras ought to mean an enormous amount of video of extraterrestrial spacecraft or whatever else "real UFO's" are supposed to be. Something like what we got for the 2013 Chelyabinsk meteor: numerous video clips from several vantage points and numerous pictures and video clips of its aftereffects in several places. This was like the L'Aigle meteorite fall of 1803, but bigger and more spectacular. But the opposite is happening, not only a fall-off in UFO sightings, but also in interest in UFO-investigation groups. So we may be seeing an anti-L'Aigle.

Here might be a good logo for UFO contactees:

The Friendly UFOnaut

(SVG version, a vector-graphics version for Inkscape and various web browsers)

It must be noted that many believers in extraterrestrial-spacecraft UFO's look down on the contactees as the lunatic fringe of their movement. This even includes many believers in UFO abductions. I suspect that a good part of it is objection to something that seems too good to be true. Who wouldn't like some Star Trek United Federation of Planets? Complete with very likable emissaries. By comparison, abductees' UFOnauts often seem like clumsy wildlife biologists, and they are certainly not very likable.

Links to other pages here

Meteorites: Unidentified Falling Objects

Some UFOlogists have compared skepticism about UFO's to skepticism about meteorites, comparing extraterrestrial spacecraft to extraterrestrial rocks, though there are also iron meteorites. The extraterrestrial hypothesis goes back to antiquity, where Anaxagoras (ca. 510 - 428 BCE) extrapolated from it to conclude that the celestial bodies were rocky or metallic objects, some of them hot enough to glow. However, Aristotle (384 - 322 BCE) believed that the celestial realm had a composition very different from the terrestial realm, so he believed that meteorites were Earth rocks blown by strong winds. Thus, the terms "meteor" and "meteorite", related to "meteorology", the science of weather. By comparison, the science of extraterrestrial rocks is "meteoritics".

Advancing to the eighteenth century, many members of the scientific community, to the extent that it could be said to exist, dismissed the extraterrestrial hypothesis as gross superstition. They preferred hypotheses like ejection from volcanoes, being blown by wind (Aristotle's), forming in the upper atmosphere like super hailstones, and meteorites being Earth rocks on the ground that got struck by lighting ("thunderstones") (1982Metic..17Q.295W Page 295 - The Eighteenth Century Meteorite Controversy: Aspects and Episodes). But the extraterrestrial theory did have some advocates, notably Ernst Florens Friedrich Chladni (1756 - 1827). In 1794, he published an account of his researches into meteorites. From his legal training, he recognized that people can be at least partially reliable in recalling sudden, fast, and unusual events, which is what meteorite falls were. He collected accounts of meteorite falls, and found them to be rather similar. From multiple accounts, he could estimate how high up they appeared and how fast they were falling. Much higher than most clouds and far too fast to be terrestrial. So fast that they made the air glow around them as they traveled. It was evident that meteorites were from elsewhere in the Universe. But Chladni's report was dry and technical, and it did not make much impact.

In 1803, there was reports of a meteorite fall in L'Aigle, France (L'Aigle (meteorite) - Wikipedia), and the French Academy of Sciences dispatched Jean-Baptiste Biot (1774 - 1862) to check out those reports of Unidentified Falling Objects. He interviewed many people there, and many people had seen them fall, people who don't usually interact with each other. He also found lots of rocks that were much alike, but very unlike other rocks from the area. So he concluded that those were extraterrestrial rocks, fragments of a big rock that broke up as it fell, and that the L'Aigle townspeople had observed these rocks falling (The meteorite fall at L'Aigle and the Biot report: exploring the cradle of meteoritics, The Meteorite Report by Jean-Baptiste Biot translated by Anne-Marie de Grazia). He wrote his report in a lively and entertaining style, and it was widely reprinted. His colleagues then reassessed other meteorites and meteorite falls, and concluded that they also were from elsewhere in the Universe.

Biot and his contemporaries quickly concluded that meteorites were produced by volcanoes on the Moon, but that hypothesis was eventually discredited. Most meteorites come from the asteroid belt, and some of them have been identified as coming from the asteroid Vesta. Various other meteorites have been identified as coming from the Moon and Mars from various chemical quirks in them.

More broadly, the shift may be interpreted in Bayesian terms. Bayes's theorem is a theorem about conditional probabilities that is both very useful and very controversial. Here it is, for data D and hypothesis H:

P(H if D) = P(D if H) * P(H) / P(D)
where one finds P(D) by making all the P(H if D)'s add up to 1 over the hypotheses. In non-mathematical terms, it is roughly
(Probability of a hypothesis for some data) ~ (probability of the data for that hypothesis) * (prior probability of that hypothesis)
Much of the controversy over applying Bayes's theorem concerns the prior probabilities of the hypotheses. How does one find them? Experimentally or a priori?

Applying Bayesian reasoning to the meteorite controversy, the anti-extraterrestrial people tended to believe that P(extraterrestrial) was vanishingly small, compared to at least one of P(volcanic), P(windblown), P(upper-atmosphere), and P(lightning-strike). But Chladni discovered that P(volcanic if meteorite speed) was vanishingly small, and the same for other non-extraterrestrial hypotheses. So to get a sensible value of P(observations), he decided to adjust P(extraterrestrial) upwards. It worked.

Friendly Contacts vs. Abductions

Here is a comparison table:

What Contacts Abductions
Appearance Good-Looking Neutral to Ugly
Friendliness Friendly Neutral to Hostile
Communication Talkative Silent
Reporter's Travels Voluntary Involuntary

To illustrate the difference further, I will quote from contactee George Adamski's book Inside the Spaceships:

I was delighted when I saw [spaceship crewwomen] Ilmuth and Kalna coming forward to greet me warmly. “Did anyone tell you about the surprise we have for you tonight?” Kalna asked, and without waiting for a reply continued enthusiastically, “A certain promise made to you will be fulfilled!”

It was to be taken to the Moon. Is there anything close to that in any UFO-abduction account?

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