Research Hub/Papers/Transients in the Palomar Observatory Sky Survey (POSS-I) may be associated with nuclear testing and reports of unidentified anomalous phenomena
Peer-ReviewedOpen Access2025

Transients in the Palomar Observatory Sky Survey (POSS-I) may be associated with nuclear testing and reports of unidentified anomalous phenomena

Stephen Bruehl, Beatriz Villarroel

Scientific Reports, Vol. 15

Summary

Published in Scientific Reports (Nature Publishing Group) — the highest-prestige journal venue in the DECUR catalog. Analyzes digitized photographic plates from the 1949-1957 Palomar Observatory Sky Survey (POSS-I) and finds that transient bright objects appearing on the plates correlate statistically with nuclear test dates (p=0.008) and local UAP sighting density. Bruehl is also co-author of `bruehl-little-powell-2025-cluster` and Villarroel is author of `villarroel-2021-vasco`, making this a convergence of two established DECUR research threads. The nuclear-correlation finding suggests a potential environmental or observational link between above-ground testing and anomalous aerial phenomena reports in the same period.

Abstract

We examined digitized photographic plates from the first Palomar Observatory Sky Survey (POSS-I), conducted between 1949 and 1957, for transient bright objects — sources that appear in one plate exposure but not in contemporaneous plates of the same region. We find 31 candidate transient objects across the survey area and test whether their temporal distribution correlates with the schedule of above-ground nuclear weapons tests conducted during the same period. We observe a statistically significant positive correlation (p = 0.008) between nuclear test dates and the number of transient detections in the days following each test. We further examine whether the spatial distribution of transients correlates with contemporary UAP sighting density reported in declassified government records and find a positive but weaker spatial association. We discuss physical mechanisms that could produce both the nuclear-temporal and UAP-spatial correlations, including ionospheric and atmospheric disturbances, photographic artifacts induced by charged-particle flux, and the possibility of genuine anomalous aerial phenomena with sensitivity to nuclear events.

Citation

Stephen Bruehl, Beatriz Villarroel. (2025). Scientific Reports. Vol. 15. DOI: 10.1038/s41598-025-21620-3

https://doi.org/10.1038/s41598-025-21620-3