Some Transients in the Palomar Observatory Sky Survey (POSS-I) May Be Associated with Above-Ground Nuclear Testing and Reports of Unidentified Anomalous Phenomena

Some Transients in the Palomar Observatory Sky Survey (POSS-I) May Be Associated with Above-Ground Nuclear Testing and Reports of Unidentified Anomalous Phenomena | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Some Transients in the Palomar Observatory Sky Survey (POSS-I) May Be Associated with Above-Ground Nuclear Testing and Reports of Unidentified Anomalous Phenomena Stephen Bruehl, Beatriz Villarroel This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6347224/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 19 Oct, 2025 Read the published version in Scientific Reports → Version 1 posted 11 You are reading this latest preprint version Abstract Transient star-like objects of unknown origin have been identified in the first Palomar Observatory Sky Survey (POSS-I) conducted prior to the first artificial satellite. We tested speculative hypotheses that some transients are related to nuclear weapons testing or unidentified anomalous phenomena (UAP) reports. A dataset comprising daily data (November 19, 1949 -April 28,1957) regarding identified transients, nuclear testing, and UAP reports was created (n=2,718 days). Results revealed significant (p = .008) associations between nuclear testing and observed transients, with transients 45% more likely on dates within +/- 1 day of nuclear testing. Significant (p<.001) associations were also noted between total number of transients and total independent UAP reports per date, with the largest association observed for dates on which at least one transient was identified (Spearman’s rho = 0.14, p = 0.015). For every additional UAP reported on a given date, there was an 8.5% increase in number of transients identified. Small but significant (p = .008) associations between nuclear testing and number of UAP reports were also noted. Findings suggest associations beyond chance between occurrence of transients and both nuclear testing and UAP reports. These findings may help elucidate the nature of POSS-I transients and strengthen empirical support for the UAP phenomenon. Physical sciences/Astronomy and planetary science/Astronomy and astrophysics/Transient astrophysical phenomena Earth and environmental sciences/Planetary science/Atmospheric chemistry Transient Unidentified Anomalous Phenomena UAP UFO Nuclear Testing Figures Figure 1 Figure 2 Introduction Transient star-like objects have been identified in sky surveys conducted prior to the launch of the first artificial satellite on October 4, 1957 1,2 . These short-lived transients (lasting less than one exposure time of 50 minutes) are absent in images taken shortly before the transients appear and in all images from subsequent surveys 3 . As reported previously in this journal 3 , in some cases multiple transients appear in a single image, exhibiting characteristics not easily accounted for by prosaic explanations (e.g., gravitational lensing, gamma ray bursts, fragmenting asteroids, plate defects) 3 , 4 . We have identified numerous transients in the Palomar Observatory Sky Survey (POSS-I) as well as in other sky surveys as part of the Vanishing and Appearing Sources during a Century of Observations (VASCO) project 1 – 3 . The source of the transients identified remains unknown and cannot be directly tested due to their historical nature. Nonetheless, examination of contemporaneous correlates of these transients may provide information useful for elucidating their possible origin. Systematic research of this type has not previously been conducted. However, anecdotal reports suggest speculative hypotheses regarding possible correlates of transients for which sufficient data are available to enable empirical testing. Possible associations of transients with nuclear weapons testing might be considered for two reasons. From 1951 until the launch of Sputnik in 1957, at least 124 above-ground nuclear tests were conducted by the United States (U.S.), Soviet Union, and Great Britain. In some circumstances, nuclear radiation is known to cause a visible glow (i.e., Cherenkov radiation) 5 . Consistent with this concept, glowing “fireballs” in the sky were reported in multiple instances to occur shortly after nuclear tests in locations where significant nuclear fallout was expected 6 , 7 . Based on such observations, we hypothesize that some transients might represent an unrecognized atmospheric effect of nuclear testing. We also considered a very different potential reason for links between nuclear testing and transients. Contemporaneous newspaper accounts and records from the Air Force’s Project Blue Book investigation of what are now called Unidentified Anomalous Phenomena (UAP) indicate that unusual, apparently metallic objects of unknown origin were reported in the sky on multiple occasions on dates surrounding nuclear weapons tests 6 . UAP have often been reported at nuclear power plants and sites involved in nuclear weapons production as well 7 , 8 . We hypothesized that if UAP seen during nuclear tests were metallic, they might reflect sunlight (or possibly emit light directly) and thus appear as transients if they were in geosynchronous orbits immediately before or after their appearance during nuclear testing. In an extension of this latter hypothesis, transients might also be associated with witness reports of UAP more broadly, outside of the nuclear testing context. Consistent with this, we note POSS-I images from July 19, 1952 and July 27, 1952, each of which exhibit multiple bright transients (see Fig. 1 ) 4 , 9 . These dates coincide with two consecutive weekends during which multiple UAP were observed for several hours both visually and on radar over Washington, D.C. 9 , 10 . We speculate that some transients could potentially be UAP in Earth orbit that, if descending into the atmosphere, might provide the stimulus for some UAP sightings. In the current study, we conducted a preliminary test of the speculative hypotheses above using a database we have created of > 100,000 transients identified in POSS-I survey images (see Methods). Each of these transients does not appear in a POSS-I image taken shortly before or in images from subsequent surveys. We examined associations of both the presence of any transient (Yes/No) and the number of transients (across the entire sky) identified on each date with: 1) dates of above-ground nuclear testing (from publicly available sources) and 2) reports of at least one UAP on that date (Yes/No) and the total number of independent UAP reported in a comprehensive database of UAP witness reports (UFOCAT; see Methods). While we anticipated significant noise in the UAP sighting data (e.g., due to witness error) and potentially in the transient data as well (e.g., misidentifications related to dust, cosmic radiation, etc.), we believed it was important to subject these novel hypotheses to direct empirical test to provide a preliminary evaluation of possible associations between observed transients and both nuclear testing and UAP sightings. Results Descriptive Characteristics Transient data were available for the period November 19, 1949 – April 28, 1957, inclusive. Of the 2,718 days in this period, transients were observed on 310 days (11.4%). In the overall sample, the number of transients per date ranged from 0 to 4,528 (across multiple locations on multiple plates), with 5% trimmed mean = 10.09 and median = 0.0. The distribution of number of transients per date was highly right-skewed (skewness = 10.35) and over-dispersed (variance = 28,938.64). Above-ground nuclear weapons tests (U.S., Soviet, and British) were conducted on 124 days (4.6%) during the study period. UAP reports were recorded in the UFOCAT database on 2,428 days during the study period (89.3%). For days on which at least one UAP sighting was reported, the 5% trimmed mean number of independent sightings (i.e., in different states or countries) was 3.77, with a median of 3.0 sighting reports. The number of UAP reports was significantly higher within a nuclear testing window (5% trimmed mean = 3.68) than outside of a nuclear testing window (5% trimmed mean = 3.31; Mann-Whitney U = 447,057, p = .008), suggesting some degree of association between these two outcomes. Association of Transients with Nuclear Weapons Testing We first tested for possible associations between occurrence of transients and nuclear weapons tests. The primary nuclear testing outcome reflected a window comprising the test date +/- 1 day (see Methods). Potential associations with transients were tested in two ways. Table 1 displays a 2 X 2 crosstabulation portraying whether each date was within a nuclear testing window (Yes/No) by whether any transient was observed on that date (Yes/No). Transients occurred significantly more often within a nuclear testing window than outside of a nuclear testing window, Chi-Square (1) = 6.94, p = .008. We note that 15.6% of nuclear test dates were associated with at least one transient whereas only 10.8% of dates outside of a nuclear testing window were associated with a transient. Our findings indicated that the relative risk ratio for a transient to occur when within a nuclear test window (relative to being outside of a nuclear test window) was 1.45 (95% CI: 1.10–1.90). Thus, a transient was 45% more likely to be observed on dates within a nuclear test window compared to outside of nuclear test window. Table 1 2 X 2 crosstabulation of transient status on a given date by whether that date fell within a nuclear testing window (test date +/- 1 day). Frequency (and percentage across nuclear testing window categories) are presented. Differences across cells are significant (p = .008). Transient Observed? Within a Nuclear Testing Window? No Yes No 2,116 (89.2%) 255 (10.8%) Yes 293 (84.4%) 54 (15.6%) Beyond dichotomous occurrence of transients, we also tested for differences in the total number of transients observed on a given date as a function of whether that date fell within a nuclear testing window. Significantly more transients were observed on dates within a nuclear testing window (5% trimmed mean = 23.40) than outside of a nuclear testing window (5% trimmed mean = 8.55; Mann-Whitney U = 431,649.5, p = .007). Association of Transients with UAP Sightings Because UAP reports were so common (at least one report on 89.3% of study dates), examination of possible links between transients and UAP sightings as dichotomous measures was of limited value (this test was not significant; Chi-Square = 2.43, p = 0.12). Instead, statistically more powerful analyses based on continuous measures were used to test associations between the number of UAP reports and number of transients observed on a given date. These analyses employed two approaches. First, nonparametric Spearman correlations revealed a small but significant correlation between number of UAP reported and number of transients observed on that date in the overall sample (Spearman’s rho = 0.064, p < .001). More informative is examination of this association for dates on which at least one transient occurred (n = 310), an analysis that eliminates bias due to the large number of zero values in the transient data (i.e., dates on which no transient was observed). This latter analysis revealed a significant association between total number of transients and total UAP reports on a given date that was more than twice as large as the association in the overall sample (Spearman’s rho = 0.138, p = 0.015). A scatterplot of this association is presented in Fig. 2 . The second analytic approach we used for testing our transient-UAP hypothesis acknowledged the highly right-skewed and over-dispersed distribution of total transients per date. This distribution approximated a negative binomial distribution and therefore we used Generalized Linear Model (GLM) analyses specifying a negative binomial distribution to test associations between number of UAP reports and number of transients each day in the overall sample. Model fit was good (Chi Square = 18.50). Results revealed a significant positive association between number of UAP reported and number of transients observed (Beta = 0.081, SE = 0.006, p < .001). The exponentiated parameter estimate [Exp(B)] = 1.085] indicated that for every additional UAP reported on a given date, there was an 8.5% increase in the number of transients observed. Finally, because both nuclear testing and UAP reports were individually associated with transients, we also explored whether their linear combination was associated with total number of transients (i.e., are the observed associations additive?). We created a new categorical variable coded as follows: 0 = No UAP on that date and the date was not within a nuclear testing window, 1 = At least one UAP report that date or the date was within a nuclear testing window, and 2 = At least one UAP report that date and the date was within a nuclear testing window. The dependent variable was total number of transients for each date, so for reasons described above we again used a GLM analysis specifying a negative binomial distribution. Results were significant, Beta = 1.073, SE = 0.0834, p < .001. Estimated marginal means (with 95% confidence intervals) for each group are presented in Table 2 . Dates with no UAP reports that were not within a nuclear testing window were associated with the fewest total transients whereas dates with at least one UAP report and that were within a nuclear testing window displayed the highest total number of transients. All pairwise differences between these individual groups were significant (p’s < .001) and the 95% confidence intervals for each did not overlap. The overall pattern of results suggests that associations of UAP reports and nuclear testing with number of observed transients may be additive. Table 2 Estimated marginal means for total number of transients identified per date across the three combined predictor groups (+/- UAP reports combined with +/- nuclear testing window). All pairwise comparisons are significant at p < .001. Combined Predictor Group Mean Total Transients Standard Error 95% Confidence Interval No UAP Reports and Not in Nuclear Window 20.0 1.24 17.69, 22.57 ≥ 1 UAP Report or Within Nuclear Window 40.6 0.89 38.88, 42.38 ≥ 1 UAP Report and Within Nuclear Window 58.4 3.25 52.39, 65.15 Discussion This study provided a preliminary test of hypothesized associations between short-lived star-like transients identified in POSS-I sky survey images from 1949-1957 and both nuclear weapons testing and reports of UAP sightings. The study premise was that identifying contemporaneous correlates of transients might help elucidate their nature and origin, which currently is unknown. Our results revealed several intriguing statistical associations. First, although not the primary study focus, we observed a small but statistically-significant association between nuclear weapons testing and increased UAP sightings. Significantly more UAP sightings were reported within nuclear weapons testing windows (test date +/- 1 day) than outside of testing windows. To our knowledge, this statistical association has not previously been reported in the peer-reviewed literature, although it is consistent with anecdotal reports of such associations 6 . Next, in tests of our primary hypotheses, we found that both dichotomous occurrence of transients and the total number of transients observed on a given date were associated with nuclear testing beyond chance. Transients were 45% more likely to be observed on dates that were within a nuclear test window than on dates not in a nuclear test window. We also note an intriguing incidental finding regarding possible nuclear testing-transients links. The last date on which a transient was observed within a nuclear testing window in this dataset was March 17, 1956, despite there being an additional 38 above-ground nuclear tests in the subsequent 13 months of the study period. A prior study of associations between UAP reports and nuclear weapons-related production and assembly sites (excluding nuclear weapons tests) concluded that elevated UAP activity at such sites began in 1948, increased dramatically and continued through 1952, but then precipitously decreased in 1953 and remained low through 1975 (end of their study period) 8 . This sudden and sustained decrease in UAP reports at nuclear production facilities in 1953 occurred despite major new nuclear weapons production and assembly facilities coming online during that time (e.g., the Savannah River and Pantex sites) 8 . Taken together, the period between 1953 and 1956 seems to mark a shift in a multiyear pattern of apparent UAP-nuclear associations. While the meaning of these parallel decreases in UAP activity at both nuclear weapons production and testing locations in the mid-1950s is unclear, they may represent convergent evidence for the validity of associations between UAP and nuclear weapons-related activity. Finally, our hypothesis of associations between transients and UAP reports was also supported. We detected a small positive correlation, well beyond chance, between the number of transients observed and the number of UAP reported on a given date. This association was strongest (Spearman’s rho = 0.14) when focusing on dates on which at least one transient occurred, an analysis that mitigates potential bias resulting from the large proportion of dates without any transient in the broader sample. This finding supports our hypothesis of potentially meaningful associations between transients and UAP reports. Other analyses indicated that for every additional UAP reported on a given date, there was an 8.5% increase in number of transients observed on that date. Overall, findings of this study supported our speculative hypotheses that transients exhibit some degree of association with both nuclear testing and reports of UAP. Our results suggest these associations are additive, with the largest number of transients seen for dates within a nuclear testing window on which at least one UAP was reported. Our findings do not definitively indicate what transients are nor do they necessarily imply causal associations. However, our results do argue against several prosaic explanations for transients. Our overall pattern of results is clearly not consistent with the proposition that most transients are due to contamination or defects in photographic plates or scanned images, or to any other local confounds at the observatory itself. These explanations would not account for the association of transients with UAP reports from multiple locations distant from the observatory. Associations between transients and both UAP and nuclear testing reported in this study also cannot be plausibly attributed to any form of observer bias, as the existence of transients was unknown at the time they occurred and the dates/times of nuclear tests were generally unknown to the individuals who were reporting the UAP. Regarding what transients might be, our findings point toward two hypotheses that could account for associations of transients with both nuclear testing and UAP reports. The first involves an unexpected and previously undocumented atmospheric phenomenon triggered by nuclear detonations or related to nuclear fallout that may serve as a stimulus for some UAP reports and appears as transients on astronomical images. While the latter is potentially plausible, effects in the atmosphere (rather than geosynchronous orbit) would be likely to result in a streak on the image over the 50 minute exposure, yet all transients appear as distinct point sources rather than streaks. The second hypothesis is more speculative, drawing on a well-known strand of UAP lore suggesting that nuclear weapons may attract UAP 6,7 . While this alleged connection has been claimed for decades based on anecdotal evidence, it has until now lacked any systematic supporting data. Within this latter hypothesis, our results could be viewed as indicating that transients are artificial objects either in high-altitude orbits around Earth (Villarroel et al. 2022) or at high altitudes within the atmosphere. Whether and how this hypothesis might be further tested remains to be determined. Regardless of what transients are ultimately determined to be, our results add to growing evidence supporting the interpretation of transients as real observations 1,3,11 rather than as emulsion defects. The small magnitude of the significant associations reported must be addressed. Detection of these small effects was enabled by the high statistical power resulting from the large sample size available. Several factors may have contributed to the small magnitude of the associations reported in this study. Associations may have been limited in part by noise in the transient data. Automated methods were applied to identification of the >100,000 transients comprising the data examined in this study. While a small subset of these have been subjected to manual confirmation, application of more sophisticated systematic validation methods employing artificial intelligence might reduce any misidentifications of transients and result in a higher signal to noise ratio, thereby increasing the magnitude of associations like those reported here. There is also undoubtedly substantial noise in the UAP data examined that could have minimized the size of observed associations. Witness reports are affected by various types of errors 12-14 and reports in the UFOCAT database that provided UAP data for the current work have not been evaluated for validity in any systematic way. Additionally, the magnitude of the associations between transients and both nuclear tests and UAP might have been limited by the fact that the Palomar Observatory from which transients were observed only provides observations from a single geographic point, whereas nuclear weapons tests and UAP reports can occur worldwide. Finally, transients may be heterogeneous in nature and derived from multiple causes, limiting the magnitude of their association with any single correlate. In conclusion, data obtained prior to launch of the first artificial satellite in 1957 reveal small but statistically-significant associations between short-lived star-like transients and both above-ground nuclear weapons testing and UAP sightings. Our findings provide additional empirical support for the validity of the UAP phenomenon and its potential connection to nuclear weapons activity, contributing data beyond eyewitness reports. The possibility that some transients may represent UAP events captured on photographic plates prior to the launch of the first artificial satellite cannot be ruled out. This study adds to the small peer-reviewed literature seeking to apply systematic scientific methods to the study of UAP-related data 7,11,15,16 . The ultimate importance of the associations reported in the current work for enhancing understanding of transients and UAP remains to be determined. Methods Data Sources. Transient Data . The initial transient dataset consisted of a list of 107,875 transients identified that occurred between 11/19/49 and 4/28/57. These transients were identified in publicly-available scanned images from the POSS-I survey available on the DSS Plate Finder website (https://archive.stsci.edu/cgi-bin/dss_plate_finder). The process used to identify transients and eliminate misidentifications was conducted via an automated workflow detailed fully in Solano et al. 1 . In brief, transients were defined as distinct star-like point sources present in POSS-I E Red images that were absent both in images taken immediately prior to the POSS-I Red image and in all subsequent images. A final criterion for classifying an object as a transient was that there were no counterparts either in PanStarrs DR1 or Gaia DR3 at less than 5 arcsec. This transient dataset contained the dates, times, and coordinates of each transient identified. For many dates, transients were noted in multiple images reflecting observations of different locations in the sky. The transient dataset (ASCII format) was converted to an SPSS for Windows data file that included a single line for each date on which at least one transient occurred, with a count variable created to summarize the total number of transients observed on each date. Nuclear Weapons Testing Data . An SPSS dataset was created from public sources which included the dates of all above-ground nuclear weapons tests during the study period. Tests conducted by the United States were identified from: https://nnss.gov/wp-content/uploads/2023/08/DOE_NV-209_Rev16.pdf. Tests conducted by the Soviet Union were identified from: https://en.wikipedia.org/wiki/List_of_nuclear_weapons_tests_of_the_Soviet_Union. Tests conducted by Great Britain were identified from: https://chrc4veterans.uk/knowledge-hub/british-nuclear-weapons-testing/. Because there was no compelling a priori reason to assume that transients would necessarily occur on the day of nuclear testing rather than the day before or after testing, we created a nuclear testing window variable (coded 1/0 for Yes/No) in this dataset to indicate whether a given date fell within a 3-day window surrounding any nuclear test (test date +/- 1 day). This decision to use a 3-day window as the primary nuclear testing outcome was made while the authors were still blinded to the transient data. UAP Witness Report Data . UAP witness report data were derived from the publicly-available comprehensive UFOCAT database maintained by the Center for UFO Studies (https://cufos.org/cufos-publications-databases/ufocat/). This database originated with the U.S. Air Force funded-University of Colorado UFO Study led by Dr. Edward Condon (1966-1968). It has been updated periodically since that time. It represents the most comprehensive publicly-available UAP sighting database covering the 1949-1957 period that was the focus of the current work. The original UFOCAT Microsoft Access database was imported into SPSS. This database contained many identical, duplicate entries (same date and location) obtained from different sources; only a single entry for each discrete report was retained. Next, to reduce the chances of duplicate reports of the same UAP described by separate witnesses on the same date and the same location (i.e., same state), only a single entry was retained in these cases. Finally, a variable reflecting the total count of UAP sightings reported from independent locations on each date was created. Procedure The final analyzed dataset began with creation of an SPSS master file with a separate record for every date within the study period, 11/19/49 to 4/28/57 (n = 2,718 days). Then, the transient database, nuclear test database, and the UAP database were merged by date with this master file. Next, dichotomous variables (coded 1/0 for Yes/No) were created to indicate whether each date in the master file was associated with at least one transient and/or with at least one UAP report. Both dichotomous and continuous variables were available for the transient data (any transient Yes/No and total number of transients identified on each date) and for the UAP data (any UAP Yes/No and total number of independent UAP reports on each date). The nuclear testing variable was only available as a dichotomous index, that is, whether each date fell within a nuclear testing window (coded 1/0 for Yes/No). Statistical Analysis All analyses were carried out using the SPSS for Windows Version 29 statistical package (IBM Corp., Armonk, NY). For testing associations between dichotomous variables [Nuclear Testing Window (Yes/No) versus Transient Observed (Yes/No)], chi-square tests were used. To aid in interpretation of the magnitude of this association between nuclear testing and transients, we adopted a relative risk approach like that commonly used in medical research. That is, we calculated the likelihood of a transient being observed (the “outcome”) based on whether its date was within a nuclear weapons testing window (the “exposure”). This relative risk ratio was calculated using an online calculator: https://www.medcalc.org/calc/relative_risk.php. Due to significantly non-normal distributions of the variables reflecting total number of transients and total number of UAP per night, differences in these variables as a function of nuclear testing were examined using the nonparametric Mann-Whitney U test. For characterizing the nature of group differences in these nonparametric tests, we present 5% trimmed means given the highly skewed distributions of these variables and that median values were generally uninformative (e.g., median total transients = 0). Also for distributional reasons, associations between these two continuous measures were tested using the nonparametric Spearman’s rho correlation. To provide an interpretive context for the magnitude of the association between total number of transients and UAP reported per night, we conducted generalized linear model (GLM) analyses, specifying a negative binomial distribution given the highly right-skewed and over-dispersed nature of the transient data. The resulting exponentiated parameter estimate was then used to derive an estimate of the effect’s magnitude (i.e., impact of number of UAP sightings on total transients observed that date) in terms of incidence rate ratio. For display purposes in Figure 2, total transients and total UAP reports have both been log10 transformed (after adding a constant [+1] to avoid zero values) in order to optimize scaling in the figure. Declarations Acknowledgements B.V is supported by a generous donor and is also funded by the Swedish Research Council (Vetenskapsrådet, grant 2024-04708). Author Contributions S.B. helped design the study, compiled the datasets, conducted and interpreted the statistical analyses, and prepared a draft of the initial manuscript. B.V. helped design the study, prepared and interpreted the transient data, and revised the draft manuscript. Data Availability Statement The final analyzed SPSS dataset will be made available by the authors upon reasonable request to Dr. Stephen Bruehl ( [email protected] ). Competing Interest Statement S.B. and B.V. have no competing interests to declare. References Solano, E., Villarroel, B., & Rodrigo, C. Discovering vanishing objects in POSS I red images using the Virtual Observatory, Monthly Notices Royal Astron Soc. 515 ,1380–1391 (2022). Villarroel, B. et al. (2019). The Vanishing and Appearing Sources during a Century of Observations Project. I. USNO Objects Missing in Modern Sky Surveys and Follow-up Observations of a “Missing Star”. Astronom J 159 , 8 (2020). Villarroel, B. et al. Exploring nine simultaneously occurring transients on April 12th 1950. Sci Rep 11 , 12794 (2021). Solano, E. et al. A bright triple transient that vanished within 50 min, Monthly Notices Royal Astron Soc. 527 , 6312–6320 (2024). Neamtan, S.M. The Čerenkov effect and the dielectric constant. Physical Rev . 92 , 1362-1367(1953). Hastings, R. Flashing sky, killing wind in UFOs & nukes: extraordinary encounters at nuclear weapons sites (2 nd Edition). 67-95 (Self-Published, 2017). Knuth, K.H. et al. The new science of unidentified aerospace-undersea phenomena (UAP). Preprint at: https://www.arxiv.org/abs/2502.06794. (2025) . Grosvenor, Sean, Larry Hancock, & Ian Porritt. 2025. UAP Indications Analysis 1945-1975 United States Atomic Warfare Complex.” Limina - The Journal of UAP Studies 2 , https://doi.org/10.59661/001c.131854, (2025) Villarroel, B. The vanishing star enigma and the 1952 Washington DC UFO wave. The Debrief . https://thedebrief.org/the-vanishing-star-enigma-and-the-1952-washington-d-c-ufo-wave/. (2024) Ruppelt, E. The Washington merry-go-round in The report on unidentified flying objects . 156-172 (Doubleday & Company, 1956). Villarroel, B. et al. A glint in the eye: Photographic plate archive searches for non-terrestrial artefacts. Acta Astronautica, 194 , 106-113 (2022). Frenda, S.J., Nichols, R.M., & Loftus, E.F. Current issues and advances in misinformation research. Curr Dir Psychol Sci. 20 , 20-23 (2011). Loftus, E.F. & Palmer, J.C. (1974). Reconstruction of automobile destruction: An example of the Interaction between language and memory. J Verbal Learn Verbal Behav. 13 , 585–589 (1974). Norman, J. F. et al. The visual perception of long outdoor distances. Sci Rep. 14 , 3207 (2024). Medina, R.M., Brewer, S.C., & Kirkpatrick, S.M. An environmental analysis of public UAP sightings and sky view potential. Sci Rep. 13 , 22213 (2023). Watters WA et al. The scientific investigation of unidentified aerial phenomena (UAP) using multimodal ground-based observatories. J Astronom Instrument 12 , 2340006. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6347224","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":486302507,"identity":"9209bbbe-966a-417e-8769-8570e12e4c1a","order_by":0,"name":"Stephen Bruehl","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAElEQVRIiWNgGAWjYBAC+QYGBmYQw54BxCiwIazF4BhUiyFYr0EaEVrYoFoMDoC1HCZCi3zzsccFFXcYDGefMXxcYHA+ccO1ww8YPu6pxalFvo0t3XjGmWcM9nw5xsYzDG4nbridZsA449lx3NYc4zGT5m07zGDYA2TwGNw2Nridw8DMc+AYHi3836R5/x1mMDjDY/6bx+AcMVp42KR5G8BazJh5DA7IQbXU4Pb+sTRzY55jh3kMe9iKgQ5LlpME+uXgjAMHcHu/+fCzxzw1h+XseZg3fuapsOPhu5388MGHA3W4HcbAwAYieFCEgFbgjSA2rKJ4bRkFo2AUjIKRBQC0yFEdminSJwAAAABJRU5ErkJggg==","orcid":"","institution":"Vanderbilt University Medical Center","correspondingAuthor":true,"prefix":"","firstName":"Stephen","middleName":"","lastName":"Bruehl","suffix":""},{"id":486302508,"identity":"f6aab48d-3e40-40a3-98f1-b02933763ebe","order_by":1,"name":"Beatriz Villarroel","email":"","orcid":"","institution":"Nordita, KTH Royal Institute of Technology and Stockholm University","correspondingAuthor":false,"prefix":"","firstName":"Beatriz","middleName":"","lastName":"Villarroel","suffix":""}],"badges":[],"createdAt":"2025-03-31 18:23:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6347224/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6347224/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-21620-3","type":"published","date":"2025-10-20T00:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":87546249,"identity":"5b28c765-9b0d-42bc-88df-593f2cb95d8d","added_by":"auto","created_at":"2025-07-25 05:07:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":308587,"visible":true,"origin":"","legend":"\u003cp\u003eFour exposures of the 3 ×3 arcmin region of sky centered on the triple transient identified in July 1952. Upper left: The POSS I red image on July 19, 1952 at 8:52 (UT) containing the triple transient just above center. Upper right: A 10 m exposure POSS I blue image of the same region taken immediately afterward with no evidence of the triple transient. Lower left and right: POSS I red (left) and blue (right) images taken two months later (September 14, 1952) showing the transient still gone. \u0026nbsp;Adapted from Solano et al. (2024).\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6347224/v1/51dfa9de70052b88a7ef6315.png"},{"id":87546247,"identity":"b5a5c15b-b633-42af-a647-922dd804db10","added_by":"auto","created_at":"2025-07-25 05:07:49","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":43845,"visible":true,"origin":"","legend":"\u003cp\u003eScatterplot of total number of transients identified by total number of independent UAP reports for dates on which at least one transient occurred (n=310). Both variables have been log10 transformed to enhance scaling for clarity.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6347224/v1/fc357a94ec6ab9dbd7532484.png"},{"id":94128711,"identity":"f3f4f231-db69-4b3a-aa13-0308c5e216e6","added_by":"auto","created_at":"2025-10-22 16:57:05","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":792341,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6347224/v1/4e46126e-636f-4f7e-98ed-2cd6ad814a56.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Some Transients in the Palomar Observatory Sky Survey (POSS-I) May Be Associated with Above-Ground Nuclear Testing and Reports of Unidentified Anomalous Phenomena","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTransient star-like objects have been identified in sky surveys conducted prior to the launch of the first artificial satellite on October 4, 1957 \u003csup\u003e1,2\u003c/sup\u003e. These short-lived transients (lasting less than one exposure time of 50 minutes) are absent in images taken shortly before the transients appear and in all images from subsequent surveys\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. As reported previously in this journal\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, in some cases multiple transients appear in a single image, exhibiting characteristics not easily accounted for by prosaic explanations (e.g., gravitational lensing, gamma ray bursts, fragmenting asteroids, plate defects)\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. We have identified numerous transients in the Palomar Observatory Sky Survey (POSS-I) as well as in other sky surveys as part of the Vanishing and Appearing Sources during a Century of Observations (VASCO) project\u003csup\u003e\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe source of the transients identified remains unknown and cannot be directly tested due to their historical nature. Nonetheless, examination of contemporaneous correlates of these transients may provide information useful for elucidating their possible origin. Systematic research of this type has not previously been conducted. However, anecdotal reports suggest speculative hypotheses regarding possible correlates of transients for which sufficient data are available to enable empirical testing.\u003c/p\u003e \u003cp\u003ePossible associations of transients with nuclear weapons testing might be considered for two reasons. From 1951 until the launch of Sputnik in 1957, at least 124 above-ground nuclear tests were conducted by the United States (U.S.), Soviet Union, and Great Britain. In some circumstances, nuclear radiation is known to cause a visible glow (i.e., Cherenkov radiation)\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Consistent with this concept, glowing \u0026ldquo;fireballs\u0026rdquo; in the sky were reported in multiple instances to occur shortly after nuclear tests in locations where significant nuclear fallout was expected\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. Based on such observations, we hypothesize that some transients might represent an unrecognized atmospheric effect of nuclear testing. We also considered a very different potential reason for links between nuclear testing and transients. Contemporaneous newspaper accounts and records from the Air Force\u0026rsquo;s Project Blue Book investigation of what are now called Unidentified Anomalous Phenomena (UAP) indicate that unusual, apparently metallic objects of unknown origin were reported in the sky on multiple occasions on dates surrounding nuclear weapons tests\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. UAP have often been reported at nuclear power plants and sites involved in nuclear weapons production as well\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. We hypothesized that if UAP seen during nuclear tests were metallic, they might reflect sunlight (or possibly emit light directly) and thus appear as transients if they were in geosynchronous orbits immediately before or after their appearance during nuclear testing.\u003c/p\u003e \u003cp\u003eIn an extension of this latter hypothesis, transients might also be associated with witness reports of UAP more broadly, outside of the nuclear testing context. Consistent with this, we note POSS-I images from July 19, 1952 and July 27, 1952, each of which exhibit multiple bright transients (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. These dates coincide with two consecutive weekends during which multiple UAP were observed for several hours both visually and on radar over Washington, D.C.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. We speculate that some transients could potentially be UAP in Earth orbit that, if descending into the atmosphere, might provide the stimulus for some UAP sightings.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the current study, we conducted a preliminary test of the speculative hypotheses above using a database we have created of \u0026gt;\u0026thinsp;100,000 transients identified in POSS-I survey images (see Methods). Each of these transients does not appear in a POSS-I image taken shortly before or in images from subsequent surveys. We examined associations of both the presence of any transient (Yes/No) and the number of transients (across the entire sky) identified on each date with: 1) dates of above-ground nuclear testing (from publicly available sources) and 2) reports of at least one UAP on that date (Yes/No) and the total number of independent UAP reported in a comprehensive database of UAP witness reports (UFOCAT; see Methods). While we anticipated significant noise in the UAP sighting data (e.g., due to witness error) and potentially in the transient data as well (e.g., misidentifications related to dust, cosmic radiation, etc.), we believed it was important to subject these novel hypotheses to direct empirical test to provide a preliminary evaluation of possible associations between observed transients and both nuclear testing and UAP sightings.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eDescriptive Characteristics\u003c/h2\u003e \u003cp\u003eTransient data were available for the period November 19, 1949 \u0026ndash; April 28, 1957, inclusive. Of the 2,718 days in this period, transients were observed on 310 days (11.4%). In the overall sample, the number of transients per date ranged from 0 to 4,528 (across multiple locations on multiple plates), with 5% trimmed mean\u0026thinsp;=\u0026thinsp;10.09 and median\u0026thinsp;=\u0026thinsp;0.0. The distribution of number of transients per date was highly right-skewed (skewness\u0026thinsp;=\u0026thinsp;10.35) and over-dispersed (variance\u0026thinsp;=\u0026thinsp;28,938.64).\u003c/p\u003e \u003cp\u003eAbove-ground nuclear weapons tests (U.S., Soviet, and British) were conducted on 124 days (4.6%) during the study period. UAP reports were recorded in the UFOCAT database on 2,428 days during the study period (89.3%). For days on which at least one UAP sighting was reported, the 5% trimmed mean number of independent sightings (i.e., in different states or countries) was 3.77, with a median of 3.0 sighting reports. The number of UAP reports was significantly higher within a nuclear testing window (5% trimmed mean\u0026thinsp;=\u0026thinsp;3.68) than outside of a nuclear testing window (5% trimmed mean\u0026thinsp;=\u0026thinsp;3.31; Mann-Whitney U\u0026thinsp;=\u0026thinsp;447,057, p\u0026thinsp;=\u0026thinsp;.008), suggesting some degree of association between these two outcomes.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAssociation of Transients with Nuclear Weapons Testing\u003c/h3\u003e\n\u003cp\u003eWe first tested for possible associations between occurrence of transients and nuclear weapons tests. The primary nuclear testing outcome reflected a window comprising the test date +/- 1 day (see Methods). Potential associations with transients were tested in two ways. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e displays a 2 X 2 crosstabulation portraying whether each date was within a nuclear testing window (Yes/No) by whether any transient was observed on that date (Yes/No). Transients occurred significantly more often within a nuclear testing window than outside of a nuclear testing window, Chi-Square (1)\u0026thinsp;=\u0026thinsp;6.94, p\u0026thinsp;=\u0026thinsp;.008. We note that 15.6% of nuclear test dates were associated with at least one transient whereas only 10.8% of dates outside of a nuclear testing window were associated with a transient. Our findings indicated that the relative risk ratio for a transient to occur when within a nuclear test window (relative to being outside of a nuclear test window) was 1.45 (95% CI: 1.10\u0026ndash;1.90). Thus, a transient was 45% more likely to be observed on dates within a nuclear test window compared to outside of nuclear test window.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e2 X 2 crosstabulation of transient status on a given date by whether that date fell within a nuclear testing window (test date +/- 1 day). Frequency (and percentage across nuclear testing window categories) are presented. Differences across cells are significant (p\u0026thinsp;=\u0026thinsp;.008).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eTransient Observed?\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWithin a Nuclear Testing Window?\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2,116 (89.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e255 (10.8%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e293 (84.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e54 (15.6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eBeyond dichotomous occurrence of transients, we also tested for differences in the total number of transients observed on a given date as a function of whether that date fell within a nuclear testing window. Significantly more transients were observed on dates within a nuclear testing window (5% trimmed mean\u0026thinsp;=\u0026thinsp;23.40) than outside of a nuclear testing window (5% trimmed mean\u0026thinsp;=\u0026thinsp;8.55; Mann-Whitney U\u0026thinsp;=\u0026thinsp;431,649.5, p\u0026thinsp;=\u0026thinsp;.007).\u003c/p\u003e\n\u003ch3\u003eAssociation of Transients with UAP Sightings\u003c/h3\u003e\n\u003cp\u003eBecause UAP reports were so common (at least one report on 89.3% of study dates), examination of possible links between transients and UAP sightings as dichotomous measures was of limited value (this test was not significant; Chi-Square\u0026thinsp;=\u0026thinsp;2.43, p\u0026thinsp;=\u0026thinsp;0.12). Instead, statistically more powerful analyses based on continuous measures were used to test associations between the \u003cem\u003enumber\u003c/em\u003e of UAP reports and \u003cem\u003enumber\u003c/em\u003e of transients observed on a given date. These analyses employed two approaches. First, nonparametric Spearman correlations revealed a small but significant correlation between number of UAP reported and number of transients observed on that date in the overall sample (Spearman\u0026rsquo;s rho\u0026thinsp;=\u0026thinsp;0.064, p\u0026thinsp;\u0026lt;\u0026thinsp;.001). More informative is examination of this association for dates on which at least one transient occurred (n\u0026thinsp;=\u0026thinsp;310), an analysis that eliminates bias due to the large number of zero values in the transient data (i.e., dates on which no transient was observed). This latter analysis revealed a significant association between total number of transients and total UAP reports on a given date that was more than twice as large as the association in the overall sample (Spearman\u0026rsquo;s rho\u0026thinsp;=\u0026thinsp;0.138, p\u0026thinsp;=\u0026thinsp;0.015). A scatterplot of this association is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe second analytic approach we used for testing our transient-UAP hypothesis acknowledged the highly right-skewed and over-dispersed distribution of total transients per date. This distribution approximated a negative binomial distribution and therefore we used Generalized Linear Model (GLM) analyses specifying a negative binomial distribution to test associations between number of UAP reports and number of transients each day in the overall sample. Model fit was good (Chi Square\u0026thinsp;=\u0026thinsp;18.50). Results revealed a significant positive association between number of UAP reported and number of transients observed (Beta\u0026thinsp;=\u0026thinsp;0.081, SE\u0026thinsp;=\u0026thinsp;0.006, p\u0026thinsp;\u0026lt;\u0026thinsp;.001). The exponentiated parameter estimate [Exp(B)]\u0026thinsp;=\u0026thinsp;1.085] indicated that for every additional UAP reported on a given date, there was an 8.5% increase in the number of transients observed.\u003c/p\u003e \u003cp\u003eFinally, because both nuclear testing and UAP reports were individually associated with transients, we also explored whether their linear combination was associated with total number of transients (i.e., are the observed associations additive?). We created a new categorical variable coded as follows: 0\u0026thinsp;=\u0026thinsp;No UAP on that date and the date was \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003enot\u003c/span\u003e within a nuclear testing window, 1\u0026thinsp;=\u0026thinsp;At least one UAP report that date \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eor\u003c/span\u003e the date was within a nuclear testing window, and 2\u0026thinsp;=\u0026thinsp;At least one UAP report that date \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eand\u003c/span\u003e the date was within a nuclear testing window. The dependent variable was total number of transients for each date, so for reasons described above we again used a GLM analysis specifying a negative binomial distribution. Results were significant, Beta\u0026thinsp;=\u0026thinsp;1.073, SE\u0026thinsp;=\u0026thinsp;0.0834, p\u0026thinsp;\u0026lt;\u0026thinsp;.001. Estimated marginal means (with 95% confidence intervals) for each group are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Dates with no UAP reports that were not within a nuclear testing window were associated with the fewest total transients whereas dates with at least one UAP report and that \u003cem\u003ewere\u003c/em\u003e within a nuclear testing window displayed the highest total number of transients. All pairwise differences between these individual groups were significant (p\u0026rsquo;s\u0026thinsp;\u0026lt;\u0026thinsp;.001) and the 95% confidence intervals for each did not overlap. The overall pattern of results suggests that associations of UAP reports and nuclear testing with number of observed transients may be additive.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEstimated marginal means for total number of transients identified per date across the three combined predictor groups (+/- UAP reports combined with +/- nuclear testing window). All pairwise comparisons are significant at p\u0026thinsp;\u0026lt;\u0026thinsp;.001.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCombined Predictor Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean Total Transients\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStandard Error\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e95% Confidence Interval\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo UAP Reports \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eand\u003c/span\u003e Not in Nuclear Window\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e20.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17.69, 22.57\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;1 UAP Report \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eor\u003c/span\u003e Within Nuclear Window\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e40.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e38.88, 42.38\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;1 UAP Report \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eand\u003c/span\u003e Within Nuclear Window\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e58.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e52.39, 65.15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study provided a preliminary test of hypothesized associations between short-lived star-like transients identified in POSS-I sky survey images from 1949-1957 and both nuclear weapons testing and reports of UAP sightings. The study premise was that identifying contemporaneous correlates of transients might help elucidate their nature and origin, which currently is unknown. \u0026nbsp;Our results revealed several intriguing statistical associations. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFirst, although not the primary study focus, we observed a small but statistically-significant association between nuclear weapons testing and increased UAP sightings. \u0026nbsp;Significantly more UAP sightings were reported within nuclear weapons testing windows (test date +/- 1 day) than outside of testing windows. \u0026nbsp;To our knowledge, this statistical association has not previously been reported in the peer-reviewed literature, although it is consistent with anecdotal reports of such associations\u003csup\u003e6\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNext, in tests of our primary hypotheses, we found that both dichotomous occurrence of transients and the total number of transients observed on a given date were associated with nuclear testing beyond chance. \u0026nbsp; Transients were 45% more likely to be observed on dates that were within a nuclear test window than on dates not in a nuclear test window. \u0026nbsp;We also note an intriguing incidental finding regarding possible nuclear testing-transients links. The last date on which a transient was observed within a nuclear testing window in this dataset was March 17, 1956, despite there being an additional 38 above-ground nuclear tests in the subsequent 13 months of the study period. \u0026nbsp; A prior study of associations between UAP reports and nuclear weapons-related production and assembly sites (excluding nuclear weapons tests) concluded that elevated UAP activity at such sites began in 1948, increased dramatically and continued through 1952, but then precipitously decreased in 1953 and remained low through 1975 (end of their study period)\u003csup\u003e8\u003c/sup\u003e. \u0026nbsp;This sudden and sustained decrease in UAP reports at nuclear production facilities in 1953 occurred despite major new nuclear weapons production and assembly facilities coming online during that time (e.g., the Savannah River and Pantex sites)\u003csup\u003e8\u003c/sup\u003e. \u0026nbsp;Taken together, the period between 1953 and 1956 seems to mark a shift in a multiyear pattern of apparent UAP-nuclear associations. \u0026nbsp;While the meaning of these parallel decreases in UAP activity at both nuclear weapons production and testing locations in the mid-1950s is unclear, they may represent convergent evidence for the validity of associations between UAP and nuclear weapons-related activity. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFinally, our hypothesis of associations between transients and UAP reports was also supported. \u0026nbsp;We detected a small positive correlation, well beyond chance, between the number of transients observed and the number of UAP reported on a given date. This association was strongest (Spearman\u0026rsquo;s rho = 0.14) when focusing on dates on which at least one transient occurred, an analysis that mitigates potential bias resulting from the large proportion of dates without any transient in the broader sample. This finding supports our hypothesis of potentially meaningful associations between transients and UAP reports. \u0026nbsp;Other analyses indicated that for every additional UAP reported on a given date, there was an 8.5% increase in number of transients observed on that date. Overall, findings of this study supported our speculative hypotheses that transients exhibit some degree of association with both nuclear testing and reports of UAP. \u0026nbsp; Our results suggest these associations are additive, with the largest number of transients seen for dates within a nuclear testing window on which at least one UAP was reported.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOur findings do not definitively indicate what transients are nor do they necessarily imply causal associations. However, our results do argue against several prosaic explanations for transients. Our overall pattern of results is clearly \u003cu\u003enot\u003c/u\u003e consistent with the proposition that most transients are due to contamination or defects in photographic plates or scanned images, or to any other local confounds at the observatory itself. \u0026nbsp;These explanations would not account for the association of transients with UAP reports from multiple locations distant from the observatory. \u0026nbsp;Associations between transients and both UAP and nuclear testing reported in this study also cannot be plausibly attributed to any form of observer bias, as the existence of transients was unknown at the time they occurred and the dates/times of nuclear tests were generally unknown to the individuals who were reporting the UAP. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eRegarding what transients might be, our findings point toward two hypotheses that could account for associations of transients with both nuclear testing and UAP reports. The first involves an unexpected and previously undocumented atmospheric phenomenon triggered by nuclear detonations or related to nuclear fallout that may serve as a stimulus for some UAP reports and appears as transients on astronomical images. While the latter is potentially plausible, effects in the atmosphere (rather than geosynchronous orbit) would be likely to result in a streak on the image over the 50 minute exposure, yet all transients appear as distinct point sources rather than streaks. \u0026nbsp; The second hypothesis is more speculative, drawing on a well-known strand of UAP lore suggesting that nuclear weapons may attract UAP\u003csup\u003e6,7\u003c/sup\u003e. While this alleged connection has been claimed for decades based on anecdotal evidence, it has until now lacked any systematic supporting data. Within this latter hypothesis, our results could be viewed as indicating that transients are artificial objects either in high-altitude orbits around Earth (Villarroel et al. 2022) or at high altitudes within the atmosphere. Whether and how this hypothesis might be further tested remains to be determined. \u0026nbsp;Regardless of what transients are ultimately determined to be, our results add to growing evidence supporting the interpretation of transients as real observations\u003csup\u003e1,3,11\u003c/sup\u003e rather than as emulsion defects.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe small magnitude of the significant associations reported must be addressed. \u0026nbsp;Detection of these small effects was enabled by the high statistical power resulting from the large sample size available. \u0026nbsp;Several factors may have contributed to the small magnitude of the associations reported in this study. \u0026nbsp;Associations may have been limited in part by noise in the transient data. \u0026nbsp;Automated methods were applied to identification of the \u0026gt;100,000 transients comprising the data examined in this study. While a small subset of these have been subjected to manual confirmation, application of more sophisticated systematic validation methods employing artificial intelligence might reduce any misidentifications of transients and result in a higher signal to noise ratio, thereby increasing the magnitude of associations like those reported here. There is also undoubtedly substantial noise in the UAP data examined that could have minimized the size of observed associations. \u0026nbsp;Witness reports are affected by various types of errors\u003csup\u003e12-14\u003c/sup\u003e and reports in the UFOCAT database that provided UAP data for the current work have not been evaluated for validity in any systematic way. \u0026nbsp;Additionally, the magnitude of the associations between transients and both nuclear tests and UAP might have been limited by the fact that the Palomar Observatory from which transients were observed only provides observations from a single geographic point, whereas nuclear weapons tests and UAP reports can occur worldwide. Finally,\u0026nbsp;transients may be heterogeneous in nature and derived from multiple causes, limiting the magnitude of their association with any single correlate. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn conclusion, data obtained prior to launch of the first artificial satellite in 1957 reveal small but statistically-significant associations between short-lived star-like transients and both above-ground nuclear weapons testing and UAP sightings. Our findings provide additional empirical support for the validity of the UAP phenomenon and its potential connection to nuclear weapons activity, contributing data beyond eyewitness reports. The possibility that some transients may represent UAP events captured on photographic plates prior to the launch of the first artificial satellite cannot be ruled out. This study adds to the small peer-reviewed literature seeking to apply systematic scientific methods to the study of UAP-related data\u003csup\u003e7,11,15,16\u003c/sup\u003e. The ultimate importance of the associations reported in the current work for enhancing understanding of transients and UAP remains to be determined. \u0026nbsp;\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eData Sources.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eTransient Data\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003eThe initial transient dataset consisted of a list of 107,875 transients identified that occurred between 11/19/49 and 4/28/57. \u0026nbsp;These transients were identified in publicly-available scanned images from the POSS-I survey available on the DSS Plate Finder website (https://archive.stsci.edu/cgi-bin/dss_plate_finder). \u0026nbsp;The process used to identify transients and eliminate misidentifications was conducted via an automated workflow detailed fully in Solano et al.\u003csup\u003e1\u003c/sup\u003e. In brief, transients were defined as distinct star-like point sources present in POSS-I E Red images that were absent both in images taken immediately prior to the POSS-I Red image and in all subsequent images. \u0026nbsp;A final criterion for classifying an object as a transient was that there were no counterparts either in PanStarrs DR1 or Gaia DR3 at less than 5 arcsec.\u003c/p\u003e\n\u003cp\u003eThis transient dataset contained the dates, times, and coordinates of each transient identified. \u0026nbsp;For many dates, transients were noted in multiple images reflecting observations of different locations in the sky. \u0026nbsp;The transient dataset (ASCII format) was converted to an SPSS for Windows data file that included a single line for each date on which at least one transient occurred, with a count variable created to summarize the total number of transients observed on each date.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNuclear Weapons Testing Data\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003eAn SPSS dataset was created from public sources which included the dates of all above-ground nuclear weapons tests during the study period. \u0026nbsp;Tests conducted by the United States were identified from:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ehttps://nnss.gov/wp-content/uploads/2023/08/DOE_NV-209_Rev16.pdf. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTests conducted by the Soviet Union were identified from: https://en.wikipedia.org/wiki/List_of_nuclear_weapons_tests_of_the_Soviet_Union. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTests conducted by Great Britain were identified from: https://chrc4veterans.uk/knowledge-hub/british-nuclear-weapons-testing/. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBecause there was no compelling \u003cem\u003ea priori\u003c/em\u003e reason to assume that transients would necessarily occur on the day of nuclear testing rather than the day before or after testing, we created a nuclear testing window variable (coded 1/0 for Yes/No) in this dataset to indicate whether a given date fell within a 3-day window surrounding any nuclear test (test date +/- 1 day). This decision to use a 3-day window as the primary nuclear testing outcome was made while the authors were still blinded to the transient data. \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eUAP Witness Report Data\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003eUAP witness report data were derived from the publicly-available comprehensive UFOCAT database maintained by the Center for UFO Studies (https://cufos.org/cufos-publications-databases/ufocat/). This database originated with the U.S. Air Force funded-University of Colorado UFO Study led by Dr. Edward Condon (1966-1968). \u0026nbsp;It has been updated periodically since that time. \u0026nbsp; It represents the most comprehensive publicly-available UAP sighting database covering the 1949-1957 period that was the focus of the current work. \u0026nbsp;The original UFOCAT Microsoft Access database was imported into SPSS. \u0026nbsp; This database contained many identical, duplicate entries (same date and location) obtained from different sources; only a single entry for each discrete report was retained. Next, to reduce the chances of duplicate reports of the same UAP described by separate witnesses on the same date and the same location (i.e., same state), only a single entry was retained in these cases. \u0026nbsp;Finally, a variable reflecting the total count of UAP sightings reported from independent locations on each date was created. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eProcedure\u003c/p\u003e\n\u003cp\u003eThe final analyzed dataset began with creation of an SPSS master file with a separate record for every date within the study period, 11/19/49 to 4/28/57 (n = 2,718 days). \u0026nbsp;Then, the transient database, nuclear test database, and the UAP database were merged by date with this master file. Next, dichotomous variables (coded 1/0 for Yes/No) were created to indicate whether each date in the master file was associated with at least one transient and/or with at least one UAP report. \u0026nbsp;Both dichotomous and continuous variables were available for the transient data (any transient Yes/No and total number of transients identified on each date) and for the UAP data (any UAP Yes/No and total number of independent UAP reports on each date). \u0026nbsp;The nuclear testing variable was only available as a dichotomous index, that is, whether each date fell within a nuclear testing window (coded 1/0 for Yes/No). \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eStatistical Analysis\u003c/p\u003e\n\u003cp\u003eAll analyses were carried out using the SPSS for Windows Version 29 statistical package (IBM Corp., Armonk, NY). \u0026nbsp;For testing associations between dichotomous variables [Nuclear Testing Window (Yes/No) versus Transient Observed (Yes/No)], chi-square tests were used. To aid in interpretation of the magnitude of this association between nuclear testing and transients, we adopted a relative risk approach like that commonly used in medical research. \u0026nbsp;That is, we calculated the likelihood of a transient being observed (the \u0026ldquo;outcome\u0026rdquo;) based on whether its date was within a nuclear weapons testing window (the \u0026ldquo;exposure\u0026rdquo;). This relative risk ratio was calculated using an online calculator: https://www.medcalc.org/calc/relative_risk.php. \u0026nbsp;Due to significantly non-normal distributions of the variables reflecting total number of transients and total number of UAP per night, differences in these variables as a function of nuclear testing were examined using the nonparametric Mann-Whitney U test. \u0026nbsp;For characterizing the nature of group differences in these nonparametric tests, we present 5% trimmed means given the highly skewed distributions of these variables and that median values were generally uninformative (e.g., median total transients = 0). \u0026nbsp;Also for distributional reasons, associations between these two continuous measures were tested using the nonparametric Spearman\u0026rsquo;s rho correlation. \u0026nbsp;To provide an interpretive context for the magnitude of the association between total number of transients and UAP reported per night, we conducted generalized linear model (GLM) analyses, specifying a negative binomial distribution given the highly right-skewed and over-dispersed nature of the transient data. The resulting exponentiated parameter estimate was then used to derive an estimate of the effect\u0026rsquo;s magnitude (i.e., impact of number of UAP sightings on total transients observed that date) in terms of incidence rate ratio. \u0026nbsp;For display purposes in Figure 2, total transients and total UAP reports have both been log10 transformed (after adding a constant [+1] to avoid zero values) in order to optimize scaling in the figure. \u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgements\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eB.V is supported by a generous donor and is also funded by the Swedish Research Council (Vetenskapsr\u0026aring;det, grant 2024-04708).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAuthor Contributions\u003c/p\u003e\n\u003cp\u003eS.B. helped design the study, compiled the datasets, conducted and interpreted the statistical analyses, and prepared a draft of the initial manuscript. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eB.V. helped design the study, prepared and interpreted the transient data, and revised the draft manuscript. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eData Availability Statement\u003c/p\u003e\n\u003cp\u003eThe final analyzed SPSS dataset will be made available by the authors upon reasonable request to Dr. Stephen Bruehl ([email protected]).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCompeting Interest Statement\u003c/p\u003e\n\u003cp\u003eS.B. and B.V. have no competing interests to declare. \u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSolano, E., Villarroel, B., \u0026amp; Rodrigo, C. 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The visual perception of long outdoor distances. \u003cem\u003eSci Rep.\u003c/em\u003e \u003cstrong\u003e14\u003c/strong\u003e, 3207 (2024). \u003c/li\u003e\n\u003cli\u003eMedina, R.M., Brewer, S.C., \u0026amp; Kirkpatrick, S.M. An environmental analysis of public UAP sightings and sky view potential. \u003cem\u003eSci Rep.\u003c/em\u003e \u003cstrong\u003e13\u003c/strong\u003e, 22213 (2023).\u003c/li\u003e\n\u003cli\u003eWatters WA et al. The scientific investigation of unidentified aerial phenomena (UAP) using multimodal ground-based observatories. \u003cem\u003eJ Astronom Instrument\u003c/em\u003e\u003cstrong\u003e12\u003c/strong\u003e, 2340006.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":true,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Transient, Unidentified Anomalous Phenomena, UAP, UFO, Nuclear Testing","lastPublishedDoi":"10.21203/rs.3.rs-6347224/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6347224/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTransient star-like objects of unknown origin have been identified in the first Palomar Observatory Sky Survey (POSS-I) conducted prior to the first artificial satellite. We tested speculative hypotheses that some transients are related to nuclear weapons testing or unidentified anomalous phenomena (UAP) reports. A dataset comprising daily data (November 19, 1949 -April 28,1957) regarding identified transients, nuclear testing, and UAP reports was created (n=2,718 days). Results revealed significant (p = .008) associations between nuclear testing and observed transients, with transients 45% more likely on dates within +/- 1 day of nuclear testing. Significant (p\u0026lt;.001) associations were also noted between total number of transients and total independent UAP reports per date, with the largest association observed for dates on which at least one transient was identified (Spearman’s rho = 0.14, p = 0.015). For every additional UAP reported on a given date, there was an 8.5% increase in number of transients identified. Small but significant (p = .008) associations between nuclear testing and number of UAP reports were also noted. Findings suggest associations beyond chance between occurrence of transients and both nuclear testing and UAP reports. These findings may help elucidate the nature of POSS-I transients and strengthen empirical support for the UAP phenomenon.\u003c/p\u003e","manuscriptTitle":"Some Transients in the Palomar Observatory Sky Survey (POSS-I) May Be Associated with Above-Ground Nuclear Testing and Reports of Unidentified Anomalous Phenomena","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-25 04:59:45","doi":"10.21203/rs.3.rs-6347224/v1","editorialEvents":[{"type":"communityComments","content":1},{"type":"decision","content":"Revision requested","date":"2025-08-28T09:48:08+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-26T06:58:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"165795692615773581762023157387180659085","date":"2025-08-24T12:48:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"77912347652012423203142725583877344258","date":"2025-05-29T14:52:52+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-23T20:11:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"289950081996456739606808282669315716097","date":"2025-04-16T09:10:18+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-15T15:29:40+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-04-15T15:12:03+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-04-11T04:39:43+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-04-09T07:25:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-03-31T18:11:30+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"27b4ff33-0f50-4afa-a88e-cdbc702e142a","owner":[],"postedDate":"July 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":51624905,"name":"Physical sciences/Astronomy and planetary science/Astronomy and astrophysics/Transient astrophysical phenomena"},{"id":51624906,"name":"Earth and environmental sciences/Planetary science/Atmospheric chemistry"}],"tags":[],"updatedAt":"2025-10-22T16:57:00+00:00","versionOfRecord":{"articleIdentity":"rs-6347224","link":"https://doi.org/10.1038/s41598-025-21620-3","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-10-20 00:00:00","publishedOnDateReadable":"October 20th, 2025"},"versionCreatedAt":"2025-07-25 04:59:45","video":"","vorDoi":"10.1038/s41598-025-21620-3","vorDoiUrl":"https://doi.org/10.1038/s41598-025-21620-3","workflowStages":[]},"version":"v1","identity":"rs-6347224","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6347224","identity":"rs-6347224","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}