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The much debated photo from Viborg first captured our attention in 1979 when it was published in the January issue of OMNI magazine. To this day, we consider it one of the most intriguing photos in existence. Both ufologists and non-ufologists who investigated the negative agree that it shows no sign of manipulation and depicts a three-dimensional object of considerable dimensions.

We close the ranks : the photo does indeed look authentic, something that cannot be said of the majority of "flying saucer" pics published in the specialized literature. The problem is to know whether it shows a solid object, or merely a cloud, as GSW suggested.

The Tactical Flight Squadron in Karup had a clear-cut opinion on this. Immediately after they had received K.K.ís police report, the Chief of Aviation stated that the unusual object was probably a rare type of cloud phenomenon, possibly related to a release of steam. In an attempt to find out more, the squadron contacted the Viborg Heating Installation. It turned out that releases of steam were quite common at their heating centres, and that, sometimes, these releases produced unusual cloud effects, especially when the bottoms of the boilers were cleaned.

As can be seen in the image below, a sudden release of steam can indeed create a cloud very similar to the "object" in the Viborg photo.

Ned KAHN at work

Not only a release of steam, also a giant flame thrower can create a jellyfish-like cloud, as can be seen in the picture to the right.

Smoke ring with distinct jellyfish features at the Burning Man Festival in Nevada.

[Photo by Waldemar HORWAT - see VO-RI-07 for an uncropped version and more info]

American artist Ned KAHN at work on one of his installations. KAHN's artworks are inspired by natural phenomena such as wind, water and fire and can be found in museums and public spaces worldwide. Here a pumpkin-shaped cloud with tentacles hovers over one of his installations.

[Image found on (more images and videos of cloud rings and tornados created by Ned KAHN can be viewed on the artist's personal web site at]
Smoke ring

Those familiar with the UFO literature may have noticed the resemblance between the Viborg photo and a series of six black and white photos taken by a U.S. army private at the military base of Fort Belvoir, Vancouver, in September 1957. The series in question show a black smoke ring with a miniature ball-shaped cloud of a lighter colour developing inside the ring [5]. An investigation conducted by astronomer William K. HARTMANN for the CONDON report [6] revealed that the ringed cloud had been caused by an atom bomb simulation, a controlled explosion frequently carried out at Fort Belvoir (usually to impress visiting officials and military cadets). A sergeant-major of the base described the technique behind these explosive demonstrations as follows : five 55-gal. drums of gasoline, diesel fuel, TNT, and white phosphorus are arranged in a circle and detonated. The blast throws up a fireball enveloped in black smoke. The top of the mushroom cloud is a stable vortex ring, which ultimately drifts away. Depending on the weather and explosion conditions, this ring sometimes never forms at all and at other times forms a perfect, persistent circle. According to the sergeant-major, the white phosphorus produces a white smoke that eventually envelops the black vortex produced by the diesel fuel.

smoke ring

A smoke ring engulfed by a ball-shaped cloud. Photos taken at Fort Belvoir, Virginia, in 1957.

[Images borrowed from FLYING SAUCERS, UFO Reports No. 4, 1967.]

It seems as if, in the 1970s, simulated atom bomb explosions experienced a burst of popularity at European military bases. Accidently or not, on October 19, 1978, one such demonstration was held at the Danish military base of Holstebro, located some 50 km (31 miles) west-southwest of Viborg. The explosion resulted in a huge smoke ring which two young passers-by described as "A white wreath which surrounded a massive black ring. The white whirling around the ring while it rose up in the sky and evaporated slowly". Fortunately, a Mrs. Birthe JENSEN, who was visiting the adjacent village of Nørre Felding that afternoon, had managed to take seven photos of the phenomenon. Mrs. JENSEN described it as "a sharply delineated black ring that dissolved and turned into a small cloud". Aware of similar incidents from the past, SUFOI collaborator Ole J. KNUDSEN contacted the base at Holstebro and was given his own recipe on how to make these wondrous rings : "You take five 200 litre petrol drums, add diesel oil and place the drums in a ring. In the middle you place 200 grams of TNT and the lot is then ignited with a white phosphor discharge. From this develops a mushroom cloud about 100 m in diameter. The top of the cloud may develop further into a concentrated black ring of smoke. Around the ring the air is whirling quite fast and in the end it loses its energy and may be seen as a small white cloud" [7].

Our picture gallery of ring-shaped vortices contains another series of photos that show a white miniature cloud developing from a disintegrating black smoke ring. These photos, three in total, were shot in Leusden, the Netherlands, in 1973. Here too the cloud was caused by an atom bomb simulation at a nearby military base.

Viborg photo (detail)

Left : the Viborg photo (detail) - Centre : photo #3 of the Leusden series (detail) - Right : photo #2 of the Nørre Felding series (detail). The images speak for themselves; all photos show dark smoke rings enveloped in white clouds.

[Respective copyrights : SUFOI Picture Library - OUDEJANS/CAELESTIA - JENSEN/SUFOI Picture Library]

In the Viborg case it is believed that the origin of the ringed cloud cannot be attributed to an explosion. In situ inquiries by HENNINGSEN learned that the military in Karup were probably right when they assumed that the cloud had been the by-product of a steam release from one of city's three heating centres in the area (while the cloud itself consisted mainly of steam, the dark ring may have been formed by soot particles). The best candidate smoke and steam blower proved to be the chimney of a plant at Odshøjvej, which is only about 320 m (350 yards) east-southeast of where the witness stood when he took his picture. In fact, had he turned his camera a little to the right, the top of the chimney would have been visible in the photo.

heating centre

Left : photo taken at the same spot from where the UFO photo was taken. The chimney of the Odshøjvej heating centre can be seen on the right. The lamp post that also appears in the initial document is visible to the left. Right : a closer view of the chimney and the heating centre.

[© Ole HENNINGSEN/SUFOI Picture Library - photos shown with permission]

sighting location

Google Earth map of the sighting location on the east bank of lake Nørresø. Indicated are (1) the spot where the witness stood when he took the photograph (the yellow arrow indicates the direction in which the photo was taken), and (2) the location of the Odshøjvej heating centre (the blue arrow indicates the direction that a hypothetical cloud of steam and smoke propelled by a southwestern wind would have travelled. The distance between (1) and (2) is approximately 320 m or 350 yards.

[Based on maps provided to us by Ole HENNINGSEN]

The weather data obtained from the meteorological station in Karup indicates that there was a strong breeze (nearly 20 knots) blowing from the southwest. As can be seen on the map above, a southwestern wind would indeed have carried smoke and steam from the chimney to the position in the picture that is occupied by the cloud.

Measured on a full frame print of the photo, we calculated that the linear width of the cloud's image on the 36x24 mm negative must have been close to 3.6 mm. This measurement can be converted to the real size of the object for any assumed distance using the formula for image formation of an object on the film of a camera. Assuming a distance of 500 m between the object and the camera lens, we get that the size of the object equals this distance divided by the focal distance (50 mm) and multiplied by the size of the image of the object on the negative (3.6 mm). In other words, if the object was 500 m (1,640 feet) away from the camera, its diameter would have been 36 m (121.39 feet).

 Our opinion

The Viborg photo is to be considered as a rare example of a miniature cumulus-type cloud developing from a black smoke ring.

The case prompted CAELESTIA to set up a new research project, the purpose of which is to track down other UFO reports that mention oval-shaped objects with a rim around their circumference and find out how many more of these reports can be attributed to ringed clouds.

Our special thanks to Ole HENNINGSEN of SUFOI for sending us scanned versions of photos and maps from the initial investigations.

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 Notes & References

[1] The International Get Acquainted Program (IGAP) was launched in 1959 by contactee George ADAMSKI, a Polish-born American who claimed to have spoken and travelled with people from Venus and Mars. The group still exists and Major PETERSEN now runs the international branch of the program. The group's web site is at

[2] UFO-Kontakt No. 1, 1979.

[3] HESEMANN, Michael, UFOs: The Secret History, Marlowe & Company, New York, 1998. Quote taken from

[4] Scandinavian UFO Information (SUFOI). Some of the group members have been active in the field of UFO research since the mid 1950s. Unlike most UFO groups, SUFOI is concerned with identifying the unidentified rather than with promoting and sustaining mysteries. The group can be contacted at The majority of the information we publish here is based on the article "Airy Spaceship over Viborg", published in SUFOI Newsletter, No. 15 (1995) and compiled by Ole HENNINGSEN, board member of SUFOI since 1963. An online version of this excellent article can be found at

[5] RANKOW, Ralph, "The Ring-Shaped UFO" in FLYING SAUCERS, UFO Reports No. 4, Fall 1967, pp. 7-10 (a scanned version of this article can be found on

[6] CONDON, Edward U. (Director) & GILLMOR, Daniel S. (Editor), Scientific Study of Unidentified Flying Objects, Vision Press Ltd, London, 1970 - first published in 1968), pp. 427-434. Generally referred to as the "CONDON report", this nearly 1,000 pages thick report issued from an official study of UFOs conducted by the University of Colorado under contract with the U.S. Air Force. An on-line version of the report can be found at

[7] UFO-Nyt No. 4, July-August 1979.