Before Sputnik · source record · preprint

Earth-Projected Clustering of Historical Optical Transients in the Palomar Observatory Sky Survey-I (POSS-I)

Stephen Bruehl; Beatriz Villarroel; Hichem Guergouri; Brian Doherty; Alina Streblyanska · 2026

AI-verified citationSRC-BRUEHL-2026

identifier / locator: arxiv:2609.09461
url: https://arxiv.org/pdf/2609.09461
verification note: text retrieved and shown to the drafter on 2026-09-10 (run 2026-09-10-draft-transients-173620); passages checked by the verify verb
reliability notes: arXiv preprint; not peer reviewed at the time shown; manuscript formatted for a Scientific Reports-style journal.
Authored by the VASCO group; same independence group as the modelling preprint and SRC-BRUEHL-2026-ML, whose ML probabilities it uses to select subsets (p≥0.70 for excess analysis, p≥0.90 for clustering).
All Earth-projected positions assume a fixed altitude of 35,786 km; the paper states (p. 19) that 'all projected locations depended on the assumed fixed altitude'.
States (p. 20) that ChatGPT was used to assist with preparation of the transient and control samples and the Bonferroni-corrected conditional binomial tests; states AI was not used for the cluster analyses themselves.
Data 'will be made available by the authors upon reasonable request' (p. 29); not public.
Misstates its companion paper's altitude result on p. 4 as '26,371 - 35,786 km above Earth' (26,371 km is the geocentric radius for 20,000 km altitude in the companion paper).
Cites popular and UAP-lore sources (a 24/7 Wall St article, a Netflix series, a memoir) for the hotspot–UAP coincidence discussion; the authors call the intelligence interpretation 'unfortunately not falsifiable' (p. 17).

Evidence drawn from this source

Supports· moderateTRN-E041

Hotspot preprint: 16 of 137 Earth-projected 5°×5° cells show Bonferroni-significant transient excess

what the source states: Projecting p ≥ 0.70 transients (11,418) and plate-aware controls (23,814) onto a 35,786 km shell and binning in 5°×5° Earth-fixed cells, the source reports that of 137 cells with ≥5 expected transients, 16 cells "exhibited a significant excess of transients relative to random control" expectations under Bonferroni-corrected conditional binomial tests (Table 1), concentrated in the eastern Pacific west of southern Mexico/Central America, the southern Gulf of Mexico, and one cell in the southwestern US.
what we infer: The excess is relative to the group's own per-plate random control, and the absolute O/E ratios are largest (up to 17.9) in cells fed by one to three plates (Supplemental Table 1). ChatGPT is stated to have assisted sample preparation and the tests. A plate whose defect rate is high would project its excess to whatever Earth cell the fixed-altitude geometry assigns it, so hotspot significance is not a test of the sky.
limitations: Fixed 35,786 km projection; locations shift with altitude
Same working catalog and ML filter as all group results
Control is the group's own construction

Stephen Bruehl (2026)AI-verified citationTRN-C119

Supports· moderateTRN-E075

Hotspot preprint: most hotspot cells are fed by more than one plate; two by a single plate (XE435) — part 1

what the source states: Decomposing each significant 5° × 5° cell by photographic plate, fourteen of the 16 cells "showed a transient excess beyond expectations on at least two" different plates.
what we infer: Useful against the single-bad-plate explanation for most cells, though the two highest-O/E cells after the Pacific ones (5 and 8, O/E 16.6 and 9.9) are single-plate. The paper also concedes (p. 17) that because both methods use the same transient sample, "their agreement alone does not rule out this possibility" of defect-driven hotspots.
limitations: Plate overlap is defined in projected coordinates, not on the sky
Per-plate significance tested at unadjusted p<0.05

Stephen Bruehl (2026)AI-verified citationTRN-C132

Context· moderateTRN-E076

Hotspot preprint: most hotspot cells are fed by more than one plate; two by a single plate (XE435) — part 2

what the source states: Of the 16 significant cells, 12 showed a transient excess "on at least three plates" when decomposed by contributing photographic plate.
what we infer: Useful against the single-bad-plate explanation for most cells, though the two highest-O/E cells after the Pacific ones (5 and 8, O/E 16.6 and 9.9) are single-plate. The paper also concedes (p. 17) that because both methods use the same transient sample, "their agreement alone does not rule out this possibility" of defect-driven hotspots.
limitations: Plate overlap is defined in projected coordinates, not on the sky
Per-plate significance tested at unadjusted p<0.05
Direction set to "context" (from "supports") by the second reader (claude-sonnet-5, 2026-09-10, run 2026-09-10-verify-transients-174405, verify-v5) at intake: The quoted figure (12 of 16 cells showing excess on at least three plates) is accurately taken from the unadjusted plate-decomposition analysis on p.6, but it is a different statistic than the one the claim actually asserts (14 cells at ≥2 plates and the 2 cells at 92.5°W tied exclusively to plate XE435). It corroborates the general theme that hotspots are not single-plate artifacts but does not itself confirm or deny the specific 14/2-cell breakdown stated in a proposed claim not admitted at intake ('Fourteen of the 16 Earth-projected hotspot cells…'), so it functions as contextual corroboration rather than direct support of that claim's specific content.

Stephen Bruehl (2026)AI-verified citationTRN-C132

Supports· moderateTRN-E077

Hotspot preprint: most hotspot cells are fed by more than one plate; two by a single plate (XE435) — part 3

what the source states: The two adjacent cells centered at 92.5° W (Hotspots 5 and 8) "were associated exclusively with a single plate, XE435" (Supplemental Table 1).
what we infer: Useful against the single-bad-plate explanation for most cells, though the two highest-O/E cells after the Pacific ones (5 and 8, O/E 16.6 and 9.9) are single-plate. The paper also concedes (p. 17) that because both methods use the same transient sample, "their agreement alone does not rule out this possibility" of defect-driven hotspots.
limitations: Plate overlap is defined in projected coordinates, not on the sky
Per-plate significance tested at unadjusted p<0.05
Second reader (claude-sonnet-5, 2026-09-10, run 2026-09-10-verify-transients-174405, verify-v5) disputes the stated direction toward TRN-C132: The quote accurately reports that Hotspots 5 and 8 were the two exceptions tied to a single plate (XE435), consistent with Supplemental Table 1 showing one contributing plate for each. However, this passage does not itself assert or establish that the other 14 hotspots showed excess on at least two plates (TRN-C132); it merely identifies the complementary exception cells, so it bears on the topic without directly supporting the claim's specific numerical finding, making 'context' the more accurate direction than 'supports'.

Stephen Bruehl (2026)AI-verified citationTRN-C132 TRN-C133

Context· moderateTRN-E078

Hotspot preprint: fixed-altitude dependence of projected locations, and a misquoted altitude range — part 1

what the source states: Transients were projected onto a spherical shell at geosynchronous altitude using line-of-sight geometry from the Palomar Observatory coordinates: "we used line-of-sight projection geometry to project all transients".
what we infer: The companion modelling preprint (SRC-VILLARROEL-2026-MODELLING) gives 20,000–35,000 km above the surface, with its χ² estimator preferring 20,000 km; 26,371 km is that paper's geocentric shell radius for a 20,000 km altitude, so the hotspot paper has conflated radius with altitude. More consequentially, every hotspot location is computed at the top of the companion's range; at 20,000 km the same transients project to different Earth cells and the geographic identifications (Sedona, White Sands, Tampico) would move.
limitations: Single assumed altitude; no sensitivity analysis across altitudes shown
Direction set to "context" (from "qualifies") by the second reader (claude-sonnet-5, 2026-09-10, run 2026-09-10-verify-transients-174405, verify-v5) at intake: The quote at p.19 accurately describes the line-of-sight projection methodology used to place transients at geosynchronous altitude, and the sourceStatement fairly restates this without overreach; the locator is correct despite the odd 'misquote at p.4' annotation, which does not correspond to any actual conflicting text there. However, this passage is purely methodological (how projections were computed) and does not itself assert, limit, or condition the truth of the specific hotspot-significance claims (C119) or non-random concentration claims (the proposed non-random-concentration claim, not admitted at intake); it merely provides background context for both, so 'context' is the correct direction rather than 'qualifies'.

Stephen Bruehl (2026)AI-verified citationTRN-C119

Supports· moderateTRN-E079

Hotspot preprint: random control samples also meet the paper's non-random clustering criterion — part 1

what the source states: Cluster analysis of the first random control sample of n = 897 locations identified three clusters with an average silhouette value of 0.50, "just meeting the minimal criterion for non-random clustering".
what we infer: Negative-control result recorded on the authors' own terms: the 0.50 criterion they state as indicating non-random clustering is met or exceeded by random points, so silhouette alone does not separate sky structure from survey footprint. Only three control draws were run; no null distribution of silhouette values is given.
limitations: Only three control samples
No formal comparison of 0.70 against the control distribution
Second reader (claude-sonnet-5, 2026-09-10, run 2026-09-10-verify-transients-174405, verify-v5) found the passage bears on TRN-C122 and a proposed claim not admitted at intake ('High-probability VASCO transients … concentrate non-randomly') and not on TRN-C121; the link dropped at intake: The quoted silhouette-0.50 finding for the first random control sample is accurately reported and located at p.9-10, and it bears on the case question. However, calling this 'qualifies' undersells that it directly instantiates and confirms TRN-C122's claim that random samples meet/exceed the 0.50 threshold (that is a support relation for C122), while it only indirectly bears on the proposed non-random-concentration claim (not admitted at intake) by raising the possibility that some hotspots are survey artifacts (a genuine qualification there). It does not bear at all on TRN-C121, which concerns the real-transient cluster silhouette of 0.70, not the control sample's result, so that claim link should be dropped.
Direction set to "supports" (from "qualifies") by the second reader (claude-sonnet-5, 2026-09-10, run 2026-09-10-verify-transients-174405, verify-v5) at intake: The quoted silhouette-0.50 finding for the first random control sample is accurately reported and located at p.9-10, and it bears on the case question. However, calling this 'qualifies' undersells that it directly instantiates and confirms TRN-C122's claim that random samples meet/exceed the 0.50 threshold (that is a support relation for C122), while it only indirectly bears on the proposed non-random-concentration claim (not admitted at intake) by raising the possibility that some hotspots are survey artifacts (a genuine qualification there). It does not bear at all on TRN-C121, which concerns the real-transient cluster silhouette of 0.70, not the control sample's result, so that claim link should be dropped.

Stephen Bruehl (2026)AI-verified citationTRN-C122

Qualifies· weakTRN-E083

Hotspot preprint: authors state the intelligence interpretation is not falsifiable — part 2

what the source states: Of the intelligence hypothesis, "it is unfortunately not falsifiable", even though it may fit the available data.
what we infer: Consistent with the ledger's verdict that TRN-C023 is presently untestable; the proponents say so of their own strongest interpretation. Bears on the claim's testability, not its truth.
limitations: Authors' self-assessment
Direction set to "qualifies" (from "context") by the second reader (claude-sonnet-5, 2026-09-10, run 2026-09-10-verify-transients-174405, verify-v5) at intake: The quote is accurately drawn from p.17 where the authors caution that the 'intelligence' interpretation, while fitting the data, is unfalsifiable. This is not merely background context but a direct qualification of confidence in the very hypothesis that underlies TRN-C023 (extraterrestrial artifact origin), so it should be marked 'qualifies' rather than 'context.' The statement is atomic, correctly located, and bears specifically on TRN-C023 since it addresses the evidentiary status of the intelligence/artifact hypothesis.

Stephen Bruehl (2026)AI-verified citationTRN-C023

Context· weakTRN-E084

Hotspot preprint: authors state the intelligence interpretation is not falsifiable — part 3

what the source states: Replication in contemporaneous data from other observatories, such as "Lick Observatory which like Mount Palomar is in California", may clarify the most appropriate interpretation of transient characteristics.
what we infer: Consistent with the ledger's verdict that TRN-C023 is presently untestable; the proponents say so of their own strongest interpretation. Bears on the claim's testability, not its truth.
limitations: Authors' self-assessment

Stephen Bruehl (2026)AI-verified citationTRN-C023