Green-white fireball with descending branch, no sound — Los Alamos area (Dec 20 1948)

On 20 December 1948, AEC Security Service Inspectors Wilson, Truett, Strang, and Skipper observed a greenish-white fireball. Dr. LaPaz derived a real path showing the object appeared at ≥10 miles altitude, descended at ~45° to a point ~2.3 miles above the observer plane, then leveled off and followed a nearly horizontal path of ~7.5 miles at 3.75–7.5 miles per second. Notably, two red lights trailed the main object and maintained constant relative positions; a sharp horizontal direction change was also observed—features noted as highly anomalous and observed again on 13 December.

“"The unusual feature of these two incidents is that there were reports of two red lights trailing the green fireball. In each case observers noted that the trailing lights retained a constant position with respect to each other and to the green light. Also, these two sightings are the only ones of all the green fireballs where a sharp change of direction in the horizontal plane was observed."”

Observed by AEC Security Service Inspectors at Los Alamos — credible, pre-briefed observers. LaPaz noted the short 8-mile baseline limited precision of path determination, so confidence is moderate-high. Speed converted from ~3.75–7.5 mi/s range; midpoint ~5.6 mi/s ≈ 20,000 mph used but marked approximate. Location coordinates derived from LaPaz report text: appearance ~35°56'N/106°30'W, disappearance ~35°57'N/106°23'W. location_approx true as these are derived from LaPaz's calculated projections, not a directly specified place name.