Independent Replication of Nuclear Test-Transient Correlations and Earth Shadow Deficit in POSS-I Photographic Plates

TL;DR

This paper independently replicates prior findings linking transient sources on photographic plates to nuclear tests and observes a deficit of transients within Earth's shadow, confirming previous statistical claims.

Contribution

It provides an independent validation of the correlation between transient detections and nuclear tests, and the Earth shadow deficit, using original data and extended analysis methods.

Findings

Confirmed temporal correlation between transients and nuclear tests (p=0.011)

Observed significant deficit of transients within Earth's shadow (p=0.006)

All transients predate Sputnik 1 launch.

Abstract

Transient sources on astronomical photographic plates are objects that appear on a single exposure but have no counterpart in modern sky surveys or on temporally adjacent plates. I present an independent replication of two findings reported by Bruehl and Villarroel (2025) and Villarroel et al. (2025): (1) a temporal correlation between transient detections on Palomar Observatory Sky Survey (POSS-I) photographic plates and atmospheric nuclear weapons tests, and (2) a deficit of transient sources within Earth's geometric shadow cone at geosynchronous orbit altitude. Using the original dataset provided by the authors, I reproduce the chi-square contingency analysis (relative risk = 1.45, p = 0.011), extend the analysis with negative binomial regression controlling for precipitation, lunar illumination, and cloud cover (all-transient incidence rate ratio = 1.80; sunlit-only IRR = 3.98, reproducing the original paper's reported findings), and confirm temporal specificity of the association via a 10,000-iteration permutation test (p = 0.006). The Earth shadow classification identifies 499 transients (0.46%) within the umbral cone in the full catalog and 142 (0.45%) in the more stringent center-of-plate subset, both significantly below the geometric expectation of approximately 1.4%, consistent with the findings of Villarroel et al. (2025). All transients predate the launch of Sputnik 1. These results confirm the core statistical claims of the original papers based on an independent analysis.