Lincoln LaPaz was an American mathematician and astronomer who founded the Institute of Meteoritics at the University of New Mexico and became one of the country's leading authorities on meteorites. In UFO history he is the scientist Air Force investigators turned to when bright green lights began crossing the skies over New Mexico's atomic installations in late 1948, and he never accepted that they were ordinary meteors.

Born in Wichita, Kansas, in 1897, LaPaz earned a mathematics degree from Fairmount College in 1920, a master's degree from Harvard in 1922 and a doctorate from the University of Chicago in 1928. He taught at Dartmouth and then at Ohio State University, where he rose to full professor in 1942. During World War II he worked as a research mathematician and then as technical director of an operations analysis section of the Second Air Force, and he studied the Japanese balloon bombs that reached the United States. That wartime work on ballistics drew him to meteorites. In 1945 he moved to Albuquerque, founded the Institute of Meteoritics, which he directed until 1966, and headed the university's department of mathematics and astronomy.

When the green fireballs appeared in December 1948, intelligence officers at Kirtland Air Force Base asked for his help. Edward Ruppelt, who later headed Project Blue Book, called LaPaz a "world-famous authority on meteorites" and wrote that after he plotted one fireball's path and searched its predicted impact area without finding anything, it was the first time LaPaz seriously doubted the objects were meteorites. LaPaz saw one himself on December 12, 1948, and argued from then on that their paths were too flat, their color too green and the absence of fragments too complete for a natural fall.

He was the principal speaker at the 1949 Los Alamos Conference on Aerial Phenomena, where the physicist Edward Teller questioned him closely and the meeting ended without an identification. Ruppelt later wrote that the conference judged the fireballs a natural phenomenon, but LaPaz held to the view that they were artificial; at various times he suggested secret military devices, foreign or American. The conference transcript released in 2026 lists those present, and neither Joseph Kaplan nor a Project Sign representative appears on it, although later retellings often place them there.

LaPaz passed away in 1985. His role returned to view in 2026, when the Pentagon's PURSUE releases published Sandia Base correspondence on the fireball reports in May and the Los Alamos transcript in July, and posts circulating the attendee list named him beside Teller and the laboratory director Norris Bradbury. Online researchers proposing new tests of the fireballs against archived White Sands ionosphere records cited his rejection of the meteor explanation. As the meteorite specialist who insisted that the green fireballs did not behave like meteorites, he gave the episode a scientific standing that few early UFO cases had.