In ufology, a close encounter is an event in which a person witnesses an unidentified flying object. This terminology and the system of classification behind it was started by astronomer and UFO researcher J. Allen Hynek, and was first suggested in his 1972 book The UFO Experience: A Scientific Inquiry. He introduced the first three kinds of encounters; more sub-types of close encounters were later added by others, but these additional categories are not universally accepted by UFO researchers, mainly because they depart from the scientific rigor that Hynek aimed to bring to ufology.
Sightings more than 500 feet (150 m) from the witness are classified as "Daylight Discs," "Nocturnal Lights," or "Radar/Visual Reports." Sightings within about 500 feet are subclassified as various types of "close encounters." Hynek and others argued that a claimed close encounter must occur within about 500 feet to greatly reduce or eliminate the possibility of misidentifying conventional aircraft or other known phenomena.
Hynek's scale became well known after being referenced in a 1977 film, Close Encounters of the Third Kind, which is named after the third level of the scale. Posters for the film recited the three levels of the scale, and Hynek himself makes a cameo appearance near the end of the film.
- 1 Hynek's scale
- 2 Extensions of Hynek's scale
- 3 See also
- 4 References
Lights in the night sky.
UFOs seen in the daytime, generally having discoidal or oval shapes.
UFO reports that seem to have radar confirmation. Though seeming to offer harder evidence of physical reality, the vagaries of radar propagation often make the ascription ambiguous.
Close Encounters of the First kind
Visual sightings of an unidentified flying object seemingly less than 500 feet away that show an appreciable angular extension and considerable detail.
Close Encounters of the Second kind
A UFO event in which a physical effect is alleged. This can be interference in the functioning of a vehicle or electronic device; animals reacting; a physiological effect such as paralysis or heat and discomfort in the witness; or some physical trace like impressions in the ground, scorched or otherwise affected vegetation, or a chemical trace.
Close Encounters of the Third kind
UFO encounters in which an animated creature is present. These include humanoids, robots, and humans who seem to be occupants or pilots of a UFO.
The UFO researcher Ted Bloecher proposed six subtypes for the close encounters of the third kind in the Hynek's scale.
- A: An entity is observed only inside the UFO.
- B: An entity is observed inside and outside the UFO.
- C: An entity is observed near to a UFO, but not going in or out.
- D: An entity is observed. No UFOs are seen by the observer, but UFO activity has been reported in the area at about the same time.
- E: An entity is observed, but no UFOs are seen and no UFO activity has been reported in the area at that time.
- F: No entity or UFOs are observed, but the subject experiences some kind of "intelligent communication".
Subtypes D, E, and F may be unrelated to the UFO phenomenon.
Extensions of Hynek's scale
Close Encounters of the Fourth kind
Hynek's erstwhile associate Jacques Vallee argued in the Journal of Scientific Exploration that a CE4 should be described as "cases when witnesses experienced a transformation of their sense of reality", so as to also include non-abduction cases where absurd, hallucinatory or dreamlike events are associated with UFO encounters.
Close Encounters of the Fifth kind
A UFO event that involves direct communication between aliens and humans. This type of close encounter was named by Steven M. Greer's CSETI group and is described as bilateral contact experiences through conscious, voluntary and proactive human-initiated cooperative communication with extraterrestrial intelligence. 
Close Encounters of the Sixth kind
Close Encounters of the Seventh kind
The creation of a human/alien hybrid, either by sexual reproduction or by artificial scientific methods.
- Extraterrestrial hypothesis
- First contact (science fiction)
- List of UFO sightings
- HC SVNT DRACONES
- Hynek, Allen J. (1998) [First published 1972]. The UFO Experience: A Scientific Inquiry. Da Capo Press. ISBN 978-1-56924-782-2.
- Clark, Jerome (1998). The UFO Book. Detroit: Visible Ink Press.
- Hynek, 1972, 1998, p. 6
- Hynek, 1972, 1998, p. 20; see also the program UFO Hunters episode "Alien Contact" aired on 23 April 2008 on the History Channel.
- Steven J. Dick (28 December 1999). The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science. Cambridge University Press. pp. 309–. ISBN 978-0-521-66361-8. Retrieved 24 October 2011.
- Donald Goldsmith; Tobias C. Owen (April 2001). The search for life in the universe. University Science Books. pp. 521–. ISBN 978-1-891389-16-0. Retrieved 24 October 2011.
- J. Allen Hynek, The UFO Experience: A Scientific Enquiry, Ballantine Books, 1972, p. 41.
- J. Allen Hynek, The UFO Experience: A Scientific Enquiry, Ballantine Books, 1972, p. 59.
- J. Allen Hynek, The UFO Experience: A Scientific Enquiry, Ballantine Books, 1972, pp. 80-1.
- J. Allen Hynek, The UFO Experience: A Scientific Enquiry, Ballantine Books, 1972, pp. 98-9.
- J. Allen Hynek, The UFO Experience: A Scientific Enquiry, Ballantine Books, 1972, p. 158.
- Hendry, Allan (August 1979). The UFO Handbook: A Guide to Investigating, Evaluating and Reporting UFO Sightings. Doubleday. ISBN 978-0-385-14348-6.
- What're close encounters of the first, second, third, fourth and fifth kind?. S.P.S. Jain. The Times of India. 22 March 2003. Retrieved 4 April 2014.
- The UFO Experience: A Scientific Enquiry. 1972. ISBN 978-1-56924-782-2.
- Vallee, Jacques. "Physical Analysis in Ten Cases of Unexplained Aerial Objects with Material Samples." 1998. Journal of Scientific Exploration. Vol. 12, No. 3., pp. 359-375. URL accessed 23 August 2009
- Haines, Richard (1999). "CE-5 Close Encounters of the Fifth Kind.". Sourcebooks, Inc.
- McCarthy, Paul (December 1, 1992). "Close encounters of the fifth kind. (communicating with UFOs)". Omni (magazine). Archived from the original on 2007-05-12. Retrieved 2007-05-12.
- Judith Joyce, The Weiser Field Guide to the Paranormal: Abductions, Apparitions, ESP, Synchronicity, and More Unexplained Phenomena from Other Realms 2010, pp. 7.
- Stuart A. Kallen, Aliens (Monsters, and Mythical Creatures) 1995, pp. 24.
- "Close Encounters with Extra-terrestrials". BBC - h2g2. 25 April 2010 [19 May 2003].
- "C.D.B. Bryan of "Close Encounters Of The Fourth Kind"". Retrieved 2007-02-13.
- "close encounters". Retrieved 2007-03-22.
- "UFOLOGY Resource Center". scifi.com. Archived from the original on 2007-03-21. Retrieved 2007-04-12.
- "UFO.WHIPNET.ORG". Retrieved 2009-11-04.
- "The Black Vault Encyclopedia Project". Retrieved 2009-11-04.
- Däniken, Erich von (1972). Chariots of the Gods. Berkley Publishing Group. ISBN 0-425-16680-5.