New Mexico Green Fireball Phenomenon (1948-1952)
Explore Visualizations
View this incident on the interactive incident map and timeline
Evidence quality · 6 components
Behavioral anomalousness · 4 components
TL;DR
A formally documented, institutionally confirmed sustained series of anomalous green luminous objects was observed over New Mexico's nuclear weapons complex (Los Alamos, Sandia Base) from 1948 to 1952. The AFSWP recorded 209 sightings with physical trace evidence (copper powder). Meteor expert Lincoln LaPaz definitively ruled out the conventional meteor explanation. Project Twinkle — the first formal U.S. government UAP scientific investigation — was commissioned specifically to resolve the phenomenon. It failed to do so.
Confirmed
- ✓209 formal sightings were documented by the Armed Forces Special Weapons Program in DOW-UAP-D017, a 116-page classified report released via PURSUE Release 2 (2026)
- ✓Copper powder physical trace evidence was recovered at Sandia Base sighting sites (confirmed in DOW-UAP-D017)
- ✓Project Twinkle was formally commissioned by the U.S. Air Force in April 1950 at Holloman AFB — the first purpose-built government scientific investigation of a UAP phenomenon
- ✓Lincoln LaPaz conducted formal field investigation for the 4th Army Counterintelligence Corps starting January 1949 and concluded the objects were inconsistent with conventional meteors
- ✓LANL scientists reported five green objects in formation over the Jemez Mountains and officially reported sightings to LANL Protective Force HQ (DOE-UAP-D002)
- ✓DOW-UAP-D017's AFSWP origin confirms the sightings were formally treated as a national security concern at the highest level of the nuclear weapons program
- ✓A February 16, 1949 conference was convened at Los Alamos specifically to address the phenomenon — attended by top nuclear scientists including Dr. Edward Teller and Dr. Joseph Kaplan
Unresolved
- ?The origin and nature of the objects — no definitive explanation was found by Project Twinkle, Project Grudge, or subsequent investigations
- ?Whether the copper powder trace evidence is directly linked to the observed objects or has an alternative source
- ?Whether Soviet reconnaissance technology, classified U.S. test vehicles, or an entirely unknown phenomenon is responsible
- ?Whether observations continued after 1952 and were suppressed or simply not formally compiled
- ?The full content of DOW-UAP-D017's 116 pages — the 2026 release is the first public access to this document
Strongest mundane explanation
New Mexico in 1948-1952 was the most active test range complex in the world — V-2 rockets, early guided missiles, and aeronautical experiments were routine at White Sands and Holloman AFB. Some researchers argue that classified test vehicles with unusual propulsion systems could account for unusual aerial phenomena. However, LaPaz's formal meteor expertise, extensive triangulation analysis, and inability to match the objects' behavior to any known experimental or natural phenomenon gives this dismissal limited purchase. The copper powder physical evidence at Sandia sighting sites has no proposed conventional source.
Between 1948 and 1952, a series of anomalous bright green luminous objects were repeatedly observed over New Mexico's nuclear weapons complex — including Los Alamos National Laboratory, Sandia Base, and the Jemez Mountains. The phenomenon was alarming enough to generate the first formal U.S. government scientific investigation of UAPs: Project Twinkle (1950-1952), commissioned by the Air Force and based at Holloman AFB. The Armed Forces Special Weapons Program (AFSWP) formally documented 209 sightings in a 116-page classified report (DOW-UAP-D017, released via PURSUE Release 2). Physical trace evidence — copper powder deposits — was recovered at Sandia Base sighting sites. Meteor expert Dr. Lincoln LaPaz of the University of New Mexico conducted extensive field investigations and definitively concluded the objects were inconsistent with conventional meteors: they followed horizontal trajectories with no downward ballistic arc, displayed no fragmentation, and produced no sonic boom pattern expected of natural fireballs. The phenomenon remained unresolved when Project Twinkle concluded in 1952. LANL scientists continued reporting observations through at least 1961 (DOE-UAP-D002).
Key Facts
- ›The green fireball phenomenon is the earliest period of systematic, institutional U.S. government UAP investigation — predating Project Blue Book
- ›The Armed Forces Special Weapons Program (AFSWP) had jurisdiction over nuclear weapons and nuclear facility security — its involvement confirms the events were treated as a nuclear security concern, not merely a curiosity
- ›The 209 documented sightings in DOW-UAP-D017 span 1948-1950 from Sandia Base alone; LANL sightings in DOE-UAP-D002 extend the documented record through 1961
- ›Project Twinkle deployed Baker-Nunn phototheodolite tracking cameras and spectrographs at Holloman AFB (New Mexico) and secondary stations to attempt photographic documentation
- ›Lincoln LaPaz's scientific authority was significant: he was one of the foremost meteor scientists in the U.S. and had consulted on recovered meteorite analyses across the Southwest. His conclusion that the objects were not meteors was not made casually
- ›The February 1949 Los Alamos conference included Dr. Edward Teller (hydrogen bomb architect), Dr. Joseph Kaplan (University of California atmospheric physicist), Lincoln LaPaz, and senior USAF officers — underscoring the institutional gravity of the phenomenon
- ›Dr. James Tuck, a British physicist who worked on implosion lens design at Los Alamos, received a letter from a LANL colleague describing green light sightings in the Jemez Mountains including a five-object formation; the LANL contact reported the sightings to LANL Protective Force HQ (DOE-UAP-D002)
- ›The copper powder recovered at Sandia Base is significant because: (a) no conventional aircraft of the era would deposit copper particulate in open terrain; (b) meteors do not deposit copper powder in this manner; (c) no classified test vehicle program of the era is publicly known to use copper in a way that would explain the deposits
- ›Project Twinkle concluded in 1952 without resolving the phenomenon. Its final report acknowledged instrument failures and coverage gaps that prevented definitive conclusions