1949 Los Alamos Conference on Aerial Phenomena

The Conference on Aerial Phenomena met at 1 p.m. on February 16, 1949, in conference room P-162 of the Los Alamos Scientific Laboratory, now Los Alamos National Laboratory. Its subject was the green fireballs, bright green lights that airline pilots, security inspectors, special agents and others had been reporting over New Mexico's atomic installations since December 1948. Sidney Newburger of the Atomic Energy Commission's Santa Fe security office opened the meeting by declaring the subject classified Secret. Those present included laboratory director Norris Bradbury, the physicist Edward Teller and four other laboratory scientists, Fourth Army intelligence officers, Lieutenant Commander Richard Mandelkorn of Sandia Base, an FBI representative, and Lincoln LaPaz, the University of New Mexico meteor specialist who had been assisting military investigators without pay.

LaPaz did most of the talking. He contrasted the fireballs with conventional meteorite falls, drawing on the one he had watched himself near Starvation Peak on the night of December 12, 1948. It appeared at full brightness instantly, glowed a yellow-green he had never seen in a meteor, crossed on a nearly horizontal path at what he took to be constant speed and lasted about two seconds before breaking into fragments that were still bright green. He said investigators had tried hard to confirm the sounds some witnesses mentioned and had obtained no such reports. According to the government's summary of the file, LaPaz said that "nothing like this, to [his] knowledge, has ever been observed in the case of meteorite drops." He added that his former boss, the UCLA physicist Joseph Kaplan, had agreed during a lecture visit to Albuquerque that these could not be conventional meteorite falls. Asked for his own explanation, LaPaz said he suspected defensive maneuvers by a higher U.S. command, an idea for which he said he had been scolded.

Teller asked most of the questions, pressing LaPaz on duration, brightness and the absence of sound, and remarked that it "certainly sounds like everything else but meteors." He then spent about twenty minutes at the blackboard estimating light output, speed, kinetic energy and shock waves, and suggested that if the fireballs were not a "material body," an "electron phenomenon" might be the cause. When Teller asked why flying discs had come up, Newburger said the Air Force now placed the discs and the fireballs in a single category, and Captain Neef reported a letter indicating that Project Sign, renamed Project Grudge, covered the New Mexico reports and had meant to send a representative. Teller said the discs were reasonably explained as meteorological balloons. Asked about German wartime experiments, LaPaz mentioned the Germans' "so-called stations in space" but said he knew of no experiments.

The meeting ended without an identification. The government's summary says the leading hypothesis was meteors entering the atmosphere at a shallow angle and high altitude, though no consensus formed. On March 22, 1949, the commission's Santa Fe office sent the transcript to Mandelkorn at Sandia Base. The reports continued, and in December 1949 the Air Force set up Project Twinkle, a network of observation and camera posts that was never fully implemented and was dropped about two years later with the conclusion that the phenomena were probably natural.

The Department of Energy's 25-page file, DOE-UAP-D004, was published on July 10, 2026, in PURSUE Release 04, with the commission's declassified cover letter. CBS News described the transcript as a record of top scientists trying and failing to explain the fireballs, and the researcher Richard Dolan featured it in his review of the release. Online readers seized on Teller's remark about flying discs and on LaPaz's reference to German space stations, which the researcher Geoff Cruickshank suggested might relate to the transient objects Beatriz Villarroel has studied on old sky survey plates. The transcript also corrects later retellings that list Joseph Kaplan and Project Sign among the attendees, since neither appears on its list of those present. It preserves a record of senior weapons scientists treating unexplained lights near the country's most secret laboratory as a technical problem they could not solve.