Unidentified flying object

See also: Extraterrestrial intelligence

Unidentified flying objects, commonly called UFOs or U.F.O.s, are any visual aerial phenomena that cannot be readily explained as natural or man-made. Most but not all UFOs are subsequently shown to be aircraft, birds, heavenly bodies, or other everyday objects. Some can also be explained as errors produced internally to a radar, electro-optical, or other sensor, and, of course, there are those that are revealed to be hoaxes. Human visual perception may also contribute errors (e.g., luminosity).

In the United States, sightings increased sharply after the Second World War and the Kenneth Arnold sighting in 1947. Most were conflated into claims of "flying saucers" or other "vehicles from outer space" that some believed were directed by extraterrestrial intelligences—some skeptics called this "mass hysteria" or "mass delusion". In 1947 the U.S. government began studying them, often in classified projects. There is, however, a distinct difference between unidentified aerial objects and these theoretical constructs. All investigators and scientists readily concede that the explanation of some aerial sightings remains unidentified even after the most intense examination. However, most dismiss the notion that there is any credible evidence that Earth is being, or has been, visited by creatures from other worlds. The U.S. government is not known to have specific investigations underway, although there is a group for the study of unidentified aerospace phenomena in the French space agency, CNES. Among scientists, electronic contact is considered much more likely, resulting in active programs such as the radio-oriented Search for Extraterrestrial Intelligence.

There is a movement, loosely called ufology or Ufology, that investigates and publishes its own observations. Much of the reporting of these organizations is anecdotal and hard to put into a scientific framework, but some of the leadership of UFO research centers, such as Mark Rodeghier of the Center for UFO Studies (CUFOS), the Mutual UFO Network (MUFON) and French born UFO researcher Jacques Vallée, participate in much more technical discussions, such as the 1997 symposium on physical evidence from UFOs. Physicist Stanton Friedman, best known for his Roswell research and the Betty and Barney Hill abduction case, is another established UFO researcher. Another well known researcher is physicist Dr. Bruce Maccabee, who was a member of National Investigations Committee on Aerial Phenomena (NICAP) and later started the Fund for UFO Research. Maccabee has investigated numerous UFO sightings including the Kennet Arnold UFO sighting, the JAL UFO sighting, the Iran Jet case in 1976 and the Gulf Breeze UFO sightings.

Other organizations, such as the Society for Scientific Exploration (SSE), do study UFOs but do not have them as their sole focus. Peter Sturrock, now Emeritus Professor of Physics at Stanford University, who directed the 1997 "Physical Evidence from UFO Reports" study, "agreed that the problem is in a very unsatisfactory state of ignorance and confusion. I expressed the opinion that this problem will be resolved only by extensive and open professional scientific investigation, and that an essential prerequisite of such research is that more scientists acquire an interest in this topic." However, Philip Klass has written that "SSE’s annual conferences typically feature several pro-UFO speakers, but no UFO-skeptics. For example, at SSE’s 1996 conference—held at the University of Virginia in Charlottesville, which SUN’s editor attended—there were four pro-UFO speakers, but no skeptics: Dr. David Jacobs, who spoke on UFO abductions; Stanton Friedman, whose remarks covered crashed saucers and the MJ-12 papers; Dr. Bruce Maccabee, who showed videos of UFOs, including one by Ed Walters (famous Gulf Breeze, Fla., UFO photographer) which seemingly showed a UFO’s ability to stop and reverse direction in a fraction of a second; and a talk by Mark Rodeghier, director of the Hynek Center for UFO Studies (CUFOS)." Jacobs, Friedman, and Maccabee were not selected to present physical evidence to the 1997 symposium.

In June 2010, James Carrion, formerly international director of the Mutual UFO Network, resigned to create the Center for UFO Truth, with a mission to "answer one question – did the United States and its allies purposely create the UFO myth as part of a cold war deception operation? It makes sense to include the subject of CUT’s research efforts in its title."

National Aviation Reporting Center on Anomalous Phenomena

The National Aviation Reporting Center on Anomalous Phenomena, NARCAP, was founded to promote aviation safety. This group considers UAPs, otherwise known as UFOs, as a rare event. The group takes no position on what the UAP phenomena represents. The group is made up of aviation experts including former and current NASA employees and aviation safety experts.

Criteria for reliable observation

Visual light spectrum

The 1997 symposium said "The panel expressed the opinion that detailed analysis of photographic evidence was unlikely by itself to yield evidence sufficient to convince a neutral scientist of the reality of a new strange phenomenon unless a number of additional detailed conditions are met.... They also expressed concern that, now that modern digital techniques are easily available in photo laboratories, it may never be possible to rule out possible hoaxes without convincing, corroborative eye-witness accounts."

Photography

Richard Haines discussed UFO photography, and observations on best photographic and interpretive practice. "...one must be careful to fully document seemingly unimportant details concerning the person taking the photograph, the social situation which surrounded the photograph(s), the camera-lens-film data, the developing-printing- enlarging activities and the manner in which the photograph came to the attention of the investigator. Since such a photograph image is only as credible as the photographer who took it, one must exercise "due diligence" in each of the above areas. Many older UFO photographs remain useless artifacts of the UFO enigma because the investigator did not or could not obtain all of the relevant background information. "

Luminosity

Considerable attention was given to luminosity of objects, which were often described as very bright lights. This is especially important in the reports of the French astronomer and UFO researcher, Jacques Vallée. He described six visual sightings, with estimates of power into the megawatt range. "Vallée cautioned the panel that the estimates of luminosity presented at the workshop are raw approximations derived from a comparison of the estimated intensity in the visible band with the intensity of known sources, such as the full moon and automobile headlights, and from assumptions concerning the distance and perhaps size of the source. The panel noted that the human eye is a very poor device for measuring absolute luminosities: the state of dark adaptation of the eye affects the amount of light reaching the retina, and different parts of the retina respond differently to light. Furthermore, the above luminosity estimates were apparently based on the assumption of isotropic emission. This may be a reasonable assumption for a natural phenomenon, but could be inappropriate if a case involves a technological device. For instance, aircraft landing lights are highly anisotropic. A 1 kW source that is beamed with a half-angle of 3.6 degrees has the same intensity as a 1 Mw isotropic emitter. Furthermore, the distance estimates may be quite dubious. Hence the power estimates derived for the above cases must be considered quite uncertain."

Radar

See also: Radar MASINT

While radar technology has improved constantly since 1947, the 1997 symposium warned against accepting radar reports without other confirmation. With UFOs, the challenge is having a radar within range of a sighting, and agetting full access to military records, as military radar is far more informative about object analysis than is civilian air traffic control. In the 1990s, however, the Swiss and French militaries provided UFO researchers with substantial access. Two incidents provided correlated visual and radar information.

However, even advanced military radars may reject contacts that do not meet preprogrammed plausibility parameters. While ballistic missile defense, space launch and surveillance, and Radar MASINT systems have a wider tactical range, typical air defense radars will not display contacts that have speeds above Mach 4-6.

Spectrometry

See also: Spectroscopic MASINT

In this context, spectrometry applies principally to the visible light spectrum, although prepared sensors should extend into the ultraviolet and infrared. Very little spectrometric data has been available. The Hessdalen Project looked into spectrometry as part of their instrument design, but found that diffraction gratings may not work in the desired environment, and spectrometry is nontrivial. Their work was in the 1990s, and there has been considerable development in multispectral scanning -- research on its use for UFOs, however, has not yet been found.

The key difficulty is that a spectrometer is a specialized instrument that must be used at the time of the sighting, but is unlikely to be available unless the UFO appears at a prepared location or a research center.

Electromagnetic interference

See also: Geophysical MASINT

Gravitational

It must be considered that UFOs might use propulsion mechanisms based on principles that do not exist in our world's technology. Nevertheless, these principles would still be bound by physical principles, such as gravity.

An ideal observation of an UFO would include measurements of the gravity fields in its area. Unfortunately, gravitometers are highly specialized, not readily available, and plausibly could be used only in areas where a UFO encounter is expected. Several groups, however, have expressed the intention to include gravity measurement in their observational stations.

Ground traces

There are advanced techniques for searching an area for specific residues, such as those of chemical weapons or industrial contaminants. In searching for UFO evidence, however, what traces would be the object of the search?

To assess a modern chemical sensor, several parameters can be combined to create a figure of merit called the receiver operating characteristic (ROC). These parameters are sensitivity, probability of correct detection, false positive rate and response time. Ideally, the device can have the parameters adjusted for specific situation. It may be more important that the device has a low false positive rate (i.e., is selective, with a low rate of false negatives) or is maximally sensitive, which means accepting false positives. ROC curves are commonly drawn to show sensitivity as a function of false positive rate for a given detection confidence and response time. Too high a false positive rate, without an operator that understands the context, can cause real alarms to be ignored. .

Injuries to vegetation

Some reports have included observations of damage to grasses and other vegetation, covering large areas that would be difficult, although not impossible, to affect evenly with readily available techniques.

Effects on witnesses

Several reports are suggestive that the witnesses may have been subjected to radiation. "Sparse evidence" seems to be indicative of microwave, infrared, visible, and ultraviolet radiation, although a few cases seem to point towards high doses of ionizing radiation such as X-rays or gamma rays. Most of the reported eye problems (sometimes long lasting) may be attributed to strong UV radiation. Superficial burns may be due to UV radiation, but deeper bums may be due to microwaves. "a notable case that occurred near Dayton, Texas, on December 29, 1980. This is known as the "Cash-Landrum" case since it involved Betty Cash, then a 51 year old business woman, and Vickie Landrum, then a 57 year old employee in a restaurant. It also involved Landrum's grandson Colby, then 7 years old. According to their reports, they encountered a large diamond-shaped object hovering above the road in front of them. Flames were belching from the bottom of the craft. The interior of the car became hot, forcing them to leave the vehicle. However, Colby and Landrum returned to the vehicle out of fear. Cash remained outside the automobile for seven to ten minutes. The object rose into the night sky and moved away. According to their reports, the object was accompanied by 23 helicopters that Cash and Landrum assumed to be military. The witnesses were initially affected mainly by the heat and the bright light, and they developed headaches. During the night, Colby vomited repeatedly and his skin turned red. The same happened to Landrum. Cash fared even worse: large water blisters formed on her face and head, and by morning her eyes had swollen shut. The three witnesses continued to have severe nausea: even water would make them vomit; they developed diarrhea, and their health deteriorated severely. Cash was taken to a hospital where she was treated as a burn patient. This was the first of more than two dozen periods of hospital confinement for Cash."

While it is difficult to assess the nature of an ionizing radiation exposure purely from clinical presentation and laboratory analysis, there is some experience in doing so. These would require blood samples to be taken shortly after exposure.

The most basic screening is to take several complete blood counts (CBC) preferably within 8-12 hours of exposure, taken every 2-3 hours. Useful data can still be obtained from CBCs taken every 4-6 hours for at least two days, with special attention to changes in the lymphocyte count. A 50% decline in absolute lymphocyte count within the first 24 hours after exposure, followed by a further, more severe decline within 48 hours, characterizes a potentially lethal exposure. If granulocyte counts show a transient increase before decline, termed an abortive rise, this may suggest the exposure is survivable.

Analysis of debris

See also: Materials MASINT

History

Since the advent of aviation, there have been both instrumental and visual detections of things that could not be explained at the time. The term "gremlin" was used to describe, among other electronic phenomena, unexplained readings from World War II radar systems. There are also many misidentifications, such as the interpretation of the radar detection of the incoming Japanese force at the Battle of Pearl Harbor as incoming friendly B-17 bombers.

When the AN/FPS-50 early warning radar, part of the Ballistic Missile Early Warning System (BMEWS), went into service in 1960, it soon reported a massive Soviet missile attack on the U.S., which proved to be due to unexpected reflections of the radar beam from the Moon.

The Kenneth Arnold sighting

UFOs became popularly known as flying saucers after a story in the East Oregonian newspaper, on June 26, 1947, reported salesman Kenneth Arnold's sighting of extremely fast-moving, "saucer-like objects" while flying a private plane. A subsequent follow-up newspaper story coined the term "flying saucer" to describe the objects that Arnold reported sighting. According to the Mutual UFO Network, there is conflict about both the UFO and flying saucer terms:

U.S. Air Force Capt. Edward J. Ruppelt says unequivocally that "UFO is the official term that I created to replace the words flying saucers". Presumably this would have been sometime between 1951, when Ruppelt took over Project Grudge (later renamed Blue Book), and September of 1953, when he left the agency and the Air Force. Elsewhere in the same book, however, Ruppelt says of Project Grudge's final 600-page report, released in December of 1949, that it was "officially titled Unidentified Flying Objects - Project Grudge, Technical Report No. 102-AC-49/15-100. But it was widely referred to as the Grudge Report." This would mean that some long forgotten anonymous Air Force staffer coined the phrase at least two years before Ruppelt did. But perhaps Ruppelt was only claiming credit for coinage of the acronym UFO.

Arnold self-published reports of the incident, which have been called hysteria by an affiliate of the Skeptical Inquirer.

Roswell incident

In July 1947, there were reports of a flying saucer crash at Roswell, New Mexico. Some reports suggest it was a classified, balloon-borne sensor, developed by the U.S., and intended to gather intelligence on Soviet nuclear weapons. Others, however, believe there was evidence of extraterrestrial origin, and possible government coverups.

On September 8, 1994, the Secretary of the Air Force, Sheila Widnall, announced that the US Air Force had completed its study to locate records relating to the Roswell incident. "Pro-UFO researchers claim that an extraterrestrial spacecraft and its alien occupants were recovered near Roswell in July of 1947, and that this fact was kept from the public."

"At the request of Congressman Steven H. Schiff (R-NM), the General Accounting Office (GAO) initiated an audit in February of 1994, to locate all records relating to the "Roswell Incident" and to determine if such records were properly handled. The GAO audit was completed and the results published by the Headquarters, U.S. Air Force in 1995. The publication is entitled "The Roswell Report: Fact vs. Fiction in the New Mexico Desert." This publication may be obtained from most U.S. Government Depository Library. The call number is ISBN 0-16- 048023-X....Prior to the interviews, Secretary Widnall released those persons from any previous security obligations that may have restricted their statements.

"The Air Force research did not locate or develop any information that the "Roswell Incident" was a UFO event nor was there any indication of a "cover-up" by the Government. Information obtained through exhaustive records searches and interviews indicated that the materials recovered near Roswell was consistent with a balloon devise of the type used in a then classified project. No records indicated or even hinted at the recovery of "alien" bodies or extraterrestrial materials."

Reports also indicate that a government task force, called Majestic-12, may have been formed to manage the alien information. The Majestic code, however, has also been associated with classified continuity of government, or "shadow government", programs that were confirmed in the Eisenhower Administration and may have existed in the Truman Administration.

Government investigation

After the Second World War, the U.S. and other governments investigated UFO reports.

Project BLUE BOOK

The major U.S. Air Force activity was called Project Blue Book, and was in existence between 1947 and 1967. It was terminated after a study called the Condon Report, coordinated by the University of Colorado, entitled, "Scientific Study of Unidentified Flying Objects;" a review of the University of Colorado's report by the National Academy of Sciences; and past UFO studies and Air Force experience investigating UFO reports during the 40s, '50s, and '60s, led the Secretary of the Air Force to determine there was no national security value to continuing investigations.

"From 1947 to 1969, a total of 12,618 sightings were reported to Project BLUE BOOK. Of these 701 remain "Unidentified." The project was headquartered at Wright-Patterson Air Force Base, whose personnel no longer receive, document or investigate UFO reports. Note below that the CIA studied until 1990.

Records of the project are in the U.S. National Archives.The National Archives searched for Majestic-12, and one document, a "Memorandum for General Twining, from Robert Cutler, Special Assistant to the President, Subject: "NCS/MJ-12 Special Studies Project" dated July 14, 1954. The memorandum, one page, refers to a briefing to take place on July 16. The memorandum does not identify MJ-12 or the purpose of the briefing." Nathan Twining was the Chairman of the Joint Chiefs of Staff. There has been some speculation, by the Federation of American Scientists and others, that this may have some relationship to what has also been called the "Eisenhower 10" continuity of government project.

The National Archives, however, found several inconsistencies regarding the NCS/MJ-12 Project document. Cutler was out of the country on the date marked on the document. It does not bear a registration number appropriate to the record series, it is not on a letterhead and is on a type of carbon paper not used for any of Cutler's other documents, and it bears a classification marking not in use until the Nixon Administration.

Another Air Force report was issued in 1997. The J. Allen Hynek Center for UFO Studies (CUFOS) (see below) disputes the Air Force report on the incident.

Condon Report

Following publication of the BLUE BOOK report, in 1967, the Air Force issued a contract, to the University of Colorado, for the study of unidentified flying objects. Brigadier General Edward B. Gillers, USAF, was the contract monitor, Dr. Thomas Rachford was the senior Air Force Scientist on the project, and the principal investigator from the University was Dr. E.U. Condon, director of the National Bureau of Standards from 1946 to 1950. The project was able to get some support from the Central Intelligence Agency.

This report was subsequently reviewed, with approval, by the National Academy of Sciences. It was also reviewed by P.A. Sturrock at the Center for Space Science and Astrophysics, Stanford University, who was active in the Society for Scientific Exploration.

Central Intelligence Agency

Central Intelligence Agency (CIA) documents indicate that the agency monitored the UFO situation from 1952. In 1952, the CIA reacted to the new rash of sightings by forming a special study group within the Office of Scientific Intelligence (OSI) and the Office of Current Intelligence (OCI). Edward Tauss reported for the group that most UFO sightings could be easily explained, but recommended that the Agency continue monitoring the problem, in coordination with the Air Force Technical Intelligence Center (ATIC). He also urged that CIA conceal its interest from the media and the public, "in view of their probable alarmist tendencies".

Upon receiving the report, Deputy Director for Intelligence (DDI) Robert Amory, Jr. assigned responsibility for the UFO investigations to OSI's Physics and Electronics Division. Each branch in the division was to contribute to the investigation, and Gordon was to coordinate closely with ATIC. Amory, who asked the group to focus on the national security implications of UFOs, was relaying DCI Walter Bedell Smith's concerns. Smith wanted to know whether or not the Air Force investigation of flying saucers was sufficiently objective and how much more money and manpower would be necessary to determine the cause of the small percentage of unexplained flying saucers. Smith believed "there was only one chance in 10,000 that the phenomenon posed a threat to the security of the country, but even that chance could not be taken." According to Smith, it was CIA's responsibility by statute to coordinate the intelligence effort required to solve the problem. Smith also wanted to know what use could be made of the UFO phenomenon in connection with US psychological warfare efforts.

Meeting with Condon team

In 1967, the Air Force issued a contract, to the University of Colorado, for the study of unidentified flying objects. The principal investigator from the University was Dr. E.U. Condon, eminent physicist and director of the National Bureau of Standards from 1946 to 1950. On 20 February 1967, Dr. Condon and four members of his team visited NPIC to familiarize the team with photogrammetric and photographic analysis capabilities of the National Photographic Interpretation Center (NPIC). Art Lundahl, the dean of photographic interpretation met with the investigators.

The meeting was allowed to discuss classified material through the SECRET level. NPIC established ground rules:

"Any work performed by NPIC to assist Dr. Condon in his investigation will not be identified as work accomplished by CIA. Dr. Condon was advised by Mr. Lundahl to make no reference to CIA in regard to this work effort. Dr. Condon stated that if he felt it necessary to obtain an official CIA comment he would make a separate distinct entry into CIA not related to contacts he has with NPIC.

"NPIC will not prepare any written comments, will not analyze information with the intent of drawing a conclusion, nor prepare written reports. NPIC personnel will be available to assist Dr. Condon by performing work of photogrammetric nature, such as attempting to measure objects imaged on photographs that may be part of Dr. Condon's analysis. Work performed by NPIC will be strictly of a technical nature using services and equipment generally not available elsewhere."

In summary, "At about 1235 the group adjourned to lunch and following lunch they left NPIC for a meeting with Brig.Gen Gillers at the Pentagon."

"Most all the discussion during the morning was of an unclassified nature dealing with primary basic fundamentals of photogrammetry, photographic analysis and problems related to the acquiring of enough information to conduct meaningful analyses."

Condon and the same group met again in May 1967 at NPIC to hear an analysis of UFO photographs taken at Zanesville, Ohio. The analysis debunked that sighting. The committee was again impressed with the technical work performed, and Condon remarked that for the first time a scientific analysis of a UFO would stand up to investigation.

National Academy of Sciences review

A panel of the National Academy of Sciences reviewed the Condon Report in 1969. They observed

We are unanimous in the opinion that this has been a very creditable effort to apply objectively the relevant techniques of science to the solution of the UFO problem. The Report recognizes that there remain UFO sightings that are not easily explained. The Report does not suggest, however, so many reasonable and possible directions in which an explanation may eventually be found, that there seems to be no reason to attribute them to an extraterrestrial source without evidence that is much more convincing. The Report also shows how difficult it is to apply scientific methods to the occasional transient sightings with any chance of success. While further study of particular aspects of the topic (e.g., atmospheric phenomena) may be useful, a study of UFOs in general is not a promising way to expand scientific understanding of the phenomena. On the basis of present knowledge the least likely explanation of UFOs is the hypothesis of extraterrrestrial visitations by intelligent beings.

French space agency

In 1977,CNES, the French space agency, set up a unit to record witness accounts of supposedly abnormal phenomena observed in the sky.

They noted there is a perfectly normal explanation for the vast majority of “sightings”, such as the Moon rising, unusual clouds or space debris re-entering the atmosphere. They classified 1600 sightings into four categories:

• Type A: Complete identification of the phenomenon
• Type B: Probable identification.
• Type C: Inadequate information for analysis
• Type D: Observations are consistent and accurate but cannot be explained in terms of conventional phenomena. 9% of sightings were in this category.

UFO Classification

In the United States, there are two well known UFO groups: the J. Allen Hynek Center for UFO Studies (CUFOS) founded by J. Allen Hynek, who was the chairman of astronomy at Northwestern University; and the Mutual UFO Network (MUFON) lead by Allen Utke, Associate Professor of Chemistry at Wisconsin State University. There is also work by a French-born researcher, Jacques Vallée.

Hynek originally doubted that the reports had any substance, but later changed his mind during his research with Project BLUE BOOK.. CUFOS collects UFO reports, maintains a UFO research library, and offers two publications concerning the UFO phenomena.

There are two major systems for classifying the reports, first based on shape and other visually observed characteristics, movement, and interaction with the environment or possible entities. In addition, some large data bases categorize by shape or other aspects of visual observations.

Some of these classifications assume not only an object that could not be explained, but also indications of a nonhuman intelligence, either extraterrestrial or terrestrial. While mainstream science does work in a Search for Extraterrestrial Intelligence, its focus has been on intelligently generated radio signals, not physical visitation.

Hynek's Classification

• Observational aspects
  • Nocturnal Disks: Objects seen in the night sky. This is the most commonly reported sighting.
  • Daylight Disks: UFOs that could be seen flying high in the sky or close to the ground. Oval or round disks are commonly seen with this type of UFO sighting.
  • Radar Visual: UFOs that are seen on radar screens while also being visually confirmed by eyewitnesses on the ground.
  • (not listed in classification, but radar-only would seem needed)
• Behavioral aspects
  • Close Encounter of the First Kind: UFOs that are seen within 200 yards of the witness. There is no interaction between the witness and the UFO.
  • Close Encounter of the Second Kind: Electrical equipment such as a car ignition may operate strangely. Other electrical equipment may malfunction while the UFO is present. Other forms of interaction may include physical effects to plants, animals or human beings. There could be traces of burned grass for example.
  • Close Encounter of the Third Kind: Seeing humanoid like creatures associated with the UFO. There is usually no interaction between the witness and the humanoid.
  • Close Encounters of the Fourth Kind: Interaction between the witness and abduction by humanoid entities.

Jacques Vallée's UFO Classification

• AN1: Viewing anomalous lights or explosions in the sky that do not affect the witness or the environment.
• AN2: Reports that show lasting effects such as flattened grass, poltergeist activity or anomalous photographs.
• AN3: Cases that include entities. This could include ghosts, yetis (Abominable Snowman), elves, spirits and cryptozoology.
• AN4: The witness reports interaction with the entities within the reality of the entities themselves. This type of experience could include near-death experiences, religious visions and out-of-body experiences (OBEs).
• MA1: A UFO that drops, maneuvers, loops.
• MA2: A UFO that includes a physical interaction with the environment while performing drops, maneuvers or loops. An example of this would be seeing a UFO near a power plant.
• MA3: Witnessing entities on board a UFO while performing the above mentioned maneuvers.
• MA4: The UFO witness observes the listed actions and goes through a transformational experience during the event.
• MA5: The UFO witness suffers serious or injury as a result of seeing a UFO in the sky.

UFO shapes

UFOs have been reported in varying shapes and colors. According to the National UFO Reporting Center statistics, 12,023 lights were reported, 6,020 triangles were reported, 5,181 circles and 4,784 disks were reported as of July 2010. Reports in the database are transcriptions of witness self-reports and are not cross-indexed, correlated, or evaluated.

Categorizing shapes is considered a challenging problem in both visual perceptual psychology and computer vision.

To recognize a previously seen object, the visual system must overcome the variability in the object's

appearance caused by factors such as illumination and pose. Developments in computer vision suggest that it may be possible to counter the in£uence of these factors, by learning to interpolate between stored views of the target object, taken under representative combinations of viewing conditions. Daily life situations, however, typically require categorization, rather than recognition, of objects. Due to the open-ended character of both natural and arti¢cial categories, categorization cannot rely on interpolation between

stored examples.

Note that the cited study deals with recognition of previously seen objects. The categorization of objects of a type never before encountered is more difficult.

The home page of the National UFO Reporting Center notes

Events across the United States and Canada on the evening of Sunday, July 04, 2010

Over the last 48 hours, NUFORC has received almost 100 similar reports of very peculiar events, which have been witnessed across the U. S. and Canada on July 4th, and perhaps on July 3rd, as well. The sightings are a phenomenon for which we have no ready explanation. Many of the reports from both days have been submitted by seemingly serious-minded individuals, many of whom apparently witnessed the events with multiple other witnesses present. The reports are similar, in that the witnesses have described seeing strange red, orange, or yellow “fireballs,” which have been seen either to hover in the night sky, or to streak overhead, sometimes individually, and on some occasions in clusters. In some instances, the objects were observed against a clear, cloudless sky, and in other cases, they were observed below solid or broken overcast.

The center did not plot the events by time, by location, or correlate appearance and movement versus time or observer position. It can be noted that on the nights of July 4 in the United States, there routinely is a high incidence of unusual lights in the sky; July 4 — U.S. Independence Day — is customarily greeted with fireworks. Indeed, an exceptionally high incidence of lights in the sky was reported on July 4, 2009, by the Mutual UFO Network.

The National UFO Reporting Center does input unverified data showing date, time, location and type of UFO sighted. The Mutual UFO Network tracks data using the live UFO Stalker map.

MUFON maintains a searchable UFO Case Management System. The researcher can search by date, shape, or location.

MUFON investigators may be assigned to a reported UFO sighting. The results of the investigation may never be revealed or be revealed once a complete investigation is done.

It should be noted that bright lights of normal origin, against a dark sky, can produce visual afterimages of substantial duration. Point sources can appear to have trails of light.

This is not to suggest that there were no unexplainable reports among these. It is extremely difficult to correlate among the witness reports. The U.S. is not covered by precision radar and there may be no other non-visual sensors. Air Traffic Control uses transponder, not radar, tracking.

Cultural effects

Characteristics of UFO reports have changed over time. Many from the late forties, at a time when aircraft speeds were approaching new levels such as the speed of sound, emphasize the speed of the object. Later reports, when high-performance aircraft became mundane, moved more to levitation and hovering. Kenneth Arnold emphasized that his objects moved as fast as 1200 mph, a speed unattainable in 1947 but routine today. "Does this prove UFOs are unreal phantoms that blend in with their times? No. Strictly, it only proves that there is a cultural dimension in our assumptions about what constitutes the behaviour of a flying saucer. People do not report everything that is present in the sky but select only what is presumed to be interesting. What is interesting changes year to year, decade to decade, century to century. We’ve forgotten that Kenneth Arnold was interesting for reasons that no longer interest us." A recent New York Times editorial, for instance, titled "Out of This World, Out of Our Minds", complete with a full-color photograph of a purported 1964 flying saucer, observes that:

...our cultural love affair with little green men has gone through the stages of many passionate relationships—the fear and hopefulness of "The Day The Earth Stood Still" in 1951; the quirky cuddliness of Ray Walston as "My Favorite Martian" in the '60s. We laugh, we cry, and then we scream again.

Off screen, however, we seem to have drifted apart: sightings rarely capture the popular imagination. Now that cellphone cameras are all but ubiquitous, there isn’t a moment that can’t be snapped—so if the truth really were out there, we’d see it. And we haven't.

That isn't to say that the number of sightings has dwindled. Groups like the National UFO Reporting Center receive hundreds of reports each month, and The Weekly World News supplies the latest in otherworldly headlines. ("Alien Tells Larry King to Leave CNN," the newspaper reported on June 29.)

...But these days, U.F.O. sightings rarely cause a stir outside of Mr. McGinness’s pages or Web sites for buffs, says John Pike of GlobalSecurity.org. "The 'Modern Myth of Things Seen in the Sky' no longer resonates with the public the way it did when a tricorder or talking computers seemed miraculous," he said.

While the public eye has been most attracted by close encounters, the Search for Extraterrestrial Intelligence project emphasizes a systematic search for radio signals.