Extraordinary claims. Ordinary investigations.

Location: Lago de Cote, Costa Rica
Date: September 4th, 1971

The unusual photography was taken by an official mapping aircraft of the Costa Rican government, flying at 10.000 feet over Lago de Cote, Arenal region. The mapping photos were automaticlly taken, and the four crewmen, including an aerial photography specialist, a geographer, a topographer and the pilot, didn’t notice anything unusual at the time. The apparent discoidal object over the lake was noticed only after developing. The filme, black and white, special for those tasks, is very big, measuring 23 cm x 23 cm, which resulted in an extraordinary clarity. According to Jacques Valleé, who analyzed the case, “one can see the cows on the field“.

Comment: This is an unexplained photographic case to this day. It involves a real UFO. Or not.

The photo came to light on the 1980s, thanks to one of the crewmen, who contacted costa-rican ufologist Ricardo Vilchez. In 1985, a second generation negative got to the hands of Jacques Valleé, who along with Richard Haines, conducted an analysis published in the Journal of Scientific Exploration. The ufologists also had access to the negatives taken just before and just after the negative with the UFO — as those were all taken by an automated system. On those adjacent images, taken 20 seconds before and after, there is nothing unusual.

This photographic case is close to perfect. The possibility of a hoax is very small, given the official source. Precise date and location are known, furthermore, the negative is of an exceptional quality. Vallé and Haines analyzed the scenario geometry and estimated that the maximum value for the disk size, assuming a real object at ground level, would have been 210 meters. Their analysis also involved computerized image processing, something rare at the time. Their conclusion:

“In summary, our analyses have suggested that an unidentified, opaque, aerial object was captured on film at a maximum distance of 10,000 feet. There are no visible means of lift or propulsion and no surface markings other than darker regions that appear to be nonrandom. This case must remain “open” until further information becomes available.”

The analysis was published along with a critical review by Marilyn E. Bruner, scientist from Lockheed Palo Alto Research Laboratory. Peer review is a common scientific practice that one seldom see on ufology, so that adds to the validity of the studies on this case. Bruner wrote that:

“While I agree that the image is very suggestive, my impression is that it probably does not represent a physical object”.

Noting several inconsistencies of the image, she noted that

“the oval image is more likely to be an artifact such as a pressure mark than a photographic image of a physical object. Such a mark could have been caused by a foreign particle trapped between two layers of the film on the supply spool.”

On February 1990, Valeé and Haines finally obtained the original negative, and conducted a new analysis. They managed to confirm their previous evaluations, no signs of hoax were detected on the film. Equally important, they evaluated Bruner’s suggestion that the disk could have been the result of some defect on the film. According to them, as the original negative had no protrusion nor depression, her hypothesis failed to be verified.

The new analysis concludes:

“In summary, our good fortune in obtaining the original negative … has resulted in confirmation of our earlier speculation that the aerial disc is certainly anomalous. While it may not be inexplicable, it is at least unidentified.”

Indeed, it remains unidentified. Could it have been a real disk more than 200 meters in diameter coming from inside Lago de Cote’s waters?  It would have been something extremely anomalous, for various reasons.

The shots taken second before and seconds later show nothing unusual. Assuming the disc was not photographed on those other images because it quickly moved away from the camera field of view, one can estimate its minimum speed if it did indeed come from the lake. Valleé and Haines themselves made the calculations, and suggested the disc in this case must have moved at a minimum speed of 2,300 km/h.

Coming from the lake and shooting at such speed, one would expect a sonic boom, and also some perturbation on the water, which would have been visible on the images taken seconds later. No such things were reported or seen.

Of course, one could always assume that such an anomalous object would have such anomalous characteristics as absence of a sonic boom or significant perturbation of the water. But those characteristics suggest the object was not material — or at least, it didn’t behave like a common material object.

It could also be that the object was actually much smaller and closer to the camera, in which case one would assume it was not that fast and didn’t touch the water. But it’s appearance in this case, with a significant part seemingly vanishing in the clear sky, is also puzzling.

See: Photo Analyses of an Aerial Disc Over Costa Rica
And also: Photo Analysis of an Aerial Disc Over Costa Rica: New Evidence