Transient Astronomical Objects and the UAP Flap of 1952

In 2024, a team led by Enrique Solano with Beatriz Villarroel as a co-author published a paper in Monthly Notices of the Royal Astronomical Society reporting a bright triple transient on Palomar Observatory Sky Survey (POSS-I) plates from July 19, 1952 the very date of the first Washington D.C. weekend. Three star-like points (about 15–16th magnitude) appear within a tiny ~10 arcsecond patch on the red plate and are gone less than an hour later on the immediately subsequent blue plate. Deep follow-up in 2023 with the 10.4-m Gran Telescopio Canarias to ~25.5 mag still finds nothing at those spots. The sources are point-like (stellar PSFs), not streaks, and show no elongation that would suggest meteors, aircraft, or moving debris across a 50-minute exposure. (Oxford Academic)

Key details from the paper and its preprint:

• When exactly? The red exposure containing the triple is timestamped 08:52 UT on July 19, 1952; the follow-on blue exposure (10 minutes) immediately afterward shows nothing. That places the optical event ~19 hours before the first radar detections near Washington (~03:40 UT on July 20 / 11:40 p.m. EDT July 19). So it’s the same calendar date (July 19) but not the same clock hour. (ar5iv)
• How odd is it? If the three points are causally linked (brightening nearly simultaneously within an exposure), their separation and the 50-minute window constrain them to be within ~6 AU of one another and no farther than ~2 light-years from Earth, otherwise light-travel time breaks the simultaneity. The team also explores microlensing scenarios, but the needed amplification and timing are extreme. Bottom line: no standard astrophysical transient class fits cleanly. (ar5iv)
• Pre-satellite era: July 1952 is pre-Sputnik, which is why these POSS plates are so valuable: if some transients are glints from objects near Earth, they can’t be human satellites. This is exactly the logic Villarroel and colleagues have been pressing in broader “VASCO” (Vanishing & Appearing Sources during a Century of Observations) work. (arXiv)

Does it connect to the Washington D.C. UAP flap?

• Temporal overlap, not spatial linkage. The triple transient was recorded at Palomar (California) while the radar-visual drama unfolded hours later over Washington, D.C. The Palomar plate images a small celestial field (RA ≈ 21h18m, Dec ≈ +50°22′)- it’s not an all-sky camera over Washington. So what we have is date-coincidence on the same weekend, not a proven, same-place same-time physical correlation. That said, in historical context it’s striking that a rare optical phenomenon pops up on the first flap date. (ar5iv)

And what about the second weekend?

Villarroel has also circulated a 2025 preprint (now peer-reviewed) analyzing “aligned, multiple-transient events” in the same POSS-I archive. One of those candidates falls on July 27, 1952, the second Washington weekend, and shows several point-like transients aligned along a narrow band within a single plate exposure. The paper quantifies one candidate as ~3.9σ significant and explicitly notes the date match to the D.C. events. Importantly, the same study reports a ~22σ deficit of such transients inside Earth’s shadow, consistent with a sunlight-reflection (glint) mechanism for at least a subset of events. (ResearchGate)

How this fits into Villarroel’s broader program

• Peer-reviewed foundation (2021): Villarroel’s team first made waves by reporting nine “simultaneous” transients on an April 12, 1950 POSS plate (not 1952). That Scientific Reports paper framed the “multiple, star-like, then gone” puzzle that later work has been chasing. (PMC)
• Catalog-first approach (2022): Solano, Villarroel & Rodrigo built a catalog of ~5,399 single-epoch red-plate transients from POSS-I (with careful cross-matching to modern surveys); the 1952 triple is drawn from this pipeline. (arXiv)
• The 1952 triple (peer-reviewed, 2024): The MNRAS paper isolates the July 19, 1952 triple and conducts new 2023 follow-up imaging to deep limits, reinforcing its reality as an astrophysical/near-Earth transient rather than a cataloguing glitch. (Oxford Academic)
• Interpretive work (methods/hypotheses): Villarroel et al. have also explored the idea that multiple, short-lived, point-like transients could be specular reflections (glints) from high-albedo objects at geosynchronous distances – not as a claim, but as an observational strategy to look for non-terrestrial artefacts (NTAs) in pre-Sputnik data where human satellites are excluded a priori. (arXiv)

The skeptic’s rejoinder (also peer-reviewed)

There is a counter-analysis also peer-reviewed. In 2024, Hambly & Blair (RAS Techniques & Instruments) argued that at least some previously reported POSS transients (not the 1952 triple specifically) have narrower, rounder profiles than neighboring stars and could be emulsion/duplication artefacts on the digitized plates. Villarroel and co-authors have replied (in a 2025 preprint) that very short flashes naturally look sharper than time-averaged stars in long exposures, so “sharper-than-stars” by itself does not prove a flaw. The debate is active; what matters for your question is that the 1952 triple underwent deep modern follow-up and persists as a real, unresolved transient in a peer-reviewed venue. (Oxford Academic)

So, what should we make of this?

• Evidence-based take: The peer-reviewed part that directly hits the D.C. flap is the July 19, 1952 triple transient; it is real by every test applied so far and extraordinary by known astrophysics. Its occurrence hours before the first night’s radar-visuals in D.C. is a fact; whether it’s physically connected is unknown. (Oxford Academic)
• Emerging (preprint) part: There appears to be another multi-point transient candidate on July 27, 1952 (the second weekend), plus the Earth-shadow deficit -both intriguing. If future refereed work upholds those statistics and rules out plate-copy artefacts on the original negatives, the case for sun-glinting objects above the atmosphere before Sputnik strengthens considerably. (ResearchGate)

Bottom line for the Washington flap context

• All parts of this that are now peer-reviewed including the MNRAS result: a genuine, unresolved triple transient on July 19, 1952, the same date as the first D.C. night, captured under strictly astronomical conditions that preclude aircraft, meteors, or satellites as straightforward explanations. That’s a suggestive and noteworthy coincidence worthy of attention, but a smoking gun like the latest peer-reviewed Palomar field plates paper. (Oxford Academic)

References

• Solano, E., Marcy, G. W., Villarroel, B., et al. (2024). A bright triple transient that vanished within 50 min. MNRAS, 527(3), 6312–6320. (peer-reviewed) (Oxford Academic)
• Villarroel, B., et al. (2021). Exploring nine simultaneously occurring transients on April 12th 1950. Scientific Reports. (peer-reviewed) (PMC)
• Solano, E., Villarroel, B., & Rodrigo, C. (2022). Discovering vanishing objects in POSS I red images using the Virtual Observatory. (not yet peer-reviewed). (arXiv)
• Villarroel, B., et al. (2025). Aligned, multiple-transient events in the First Palomar Sky Survey. (peer-reviewed; reports July 27, 1952 candidate and Earth-shadow deficit). (Nature)
• Hambly, N. C., & Blair, A. (2024). On the nature of apparent transient sources on the NGS-POSS glass copy plates. RAS Techniques & Instruments, 3(1), 73–79. (peer-reviewed critique) (Oxford Academic)
• Villarroel, B., et al. (2021). A glint in the eye: photographic plate archive searches for non-terrestrial artefacts. (methods paper proposing glint-based searches for NTAs). (arXiv)
• Villarroel, B., Marcy, G.W., Geier, S. et al. (2021). Exploring nine simultaneously occurring transients on April 12th 1950. Sci Rep 11, 12794 (2021). (Nature)

Claims Taxonomy

Verified (peer-reviewed):

• Triple transient on 1952-07-19 (UT 08:52) appearing on a POSS-I red plate and gone <1 hr later; no counterparts down to ~25.5 mag; PSF-consistent with stars; no elongation; follow-up non-detections in later surveys. (Oxford Academic)
• Aligned, multiple transients including a July 27, 1952 candidate; large deficit of events in Earth’s shadow suggesting sun-reflection plays a role. (Methodologically serious, but still a preprint.) (ResearchGate)

Probable (but needs further peer review):

None demonstrated.

Disputed:

• Cause of these transients: plate artefact vs real optical flashes/glints vs exotic astrophysics (e.g., lensing) vs near-Earth objects; peer-reviewed skeptical critique exists and is being actively rebutted in the literature. (Oxford Academic)

Legend/Misidentification:

None demonstrated.

Origin and Ingestion Date