The Green Fireballs of New Mexico

Northern New Mexico. December 5, 1948. Two plane crews, on separate flights, watched a brilliant green object cross the sky south-to-north, moving — they all said — too slowly to be a meteor, and the wrong color besides. It was the first of thirty within ten weeks, every one clustered over the same patch of desert: Los Alamos, Sandia Base, White Sands.

By February 1949, the government was worried. The Director of Army Intelligence at Fourth Army Headquarters in Texas wrote that the fireballs "[may be] the result of radiological warfare experiments by a foreign power" — and that, occurring as they were in the vicinity of America's most sensitive installations, "a scientific board [should]…study the situation."

The board convened at Los Alamos on February 16, 1949. Edward Teller was in attendance — the future father of the hydrogen bomb. Lincoln LaPaz was at the table. The agenda was, in effect: are these ours, are they someone else's, or are they meteors? The conclusion did not satisfy anyone in the room. The phenomena were, the report said, "probably of natural origin." Probably.

Lincoln LaPaz, in 1949, was the head of the Institute of Meteoritics at the University of New Mexico — the country's leading expert on what falls out of the sky. If anyone could rule on whether the fireballs were meteors, it was him. He carried a color spectrum chart and interviewed more than a hundred witnesses, asking each to point to the exact shade of green they had seen. Time after time, witnesses pointed to the same vivid, particular green — markedly different from the pale, yellowish-green sometimes reported in genuine meteor falls.

LaPaz traced flight paths, scoured the impact zones, and found nothing. No fragments. No crater. No charred mesquite. A meteor that does not deposit a meteorite is not a meteor.

He kept a list of other complications. The fireballs moved too slowly. They moved level. They did not trail sparks or dust. He sent it all to the Air Force Office of Special Investigations, on the record, and waited for the explanation that did not come.

In December 1949, the Air Force funded a small program to settle the question: photograph one. Project Twinkle set up three cinetheodolite stations near White Sands — the same instruments used to track V-2 launches — with two cameras and a spectrograph operator at each station, watching every clear night. Twinkle ran for roughly two years. It photographed nothing. Its final report concluded that the phenomena remained unexplained but were not "extraterrestrial bodies" — a kind of small-print honesty the rest of the document doesn't earn.

By the mid-1950s LaPaz had moved off "probably of natural origin." His final view, expressed to the Atomic Energy Commission and, later, to Edward J. Ruppelt — who headed Project Blue Book in its first years — was that the fireballs were probably either an "unconventional defensive device" of our own, secretly fielded, or someone else's. He never claimed to have the answer. He claimed that the answer wasn't natural. The Air Force did not endorse his conclusion. They also did not contradict it. Project Blue Book, which absorbed the case in 1952, left it as "unidentified."

Seventy-seven years. The official record still reads: probably of natural origin, three decimal places of uncertainty. Project Twinkle's photographs do not exist because they were never taken. Lincoln LaPaz died in 1985 with the fireballs unexplained — though "unexplained" was, in his framing, a polite word.

On May 22, 2026, the U.S. Department of War's second PURSUE tranche included historical material on the green fireballs of 1949. Nothing in it closed the question. The record is still what LaPaz left it: probably-of-natural-origin, with one professional opinion attached saying otherwise.