Transients in the Palomar Observatory Sky Survey

[Gary C]

The authors frequently use the word "atomic" in the paper, even when clearly referring to what would normally be described as "nuclear" or "thermonuclear" items/ topics. It is as if they're unfamiliar with the subject matter. Only fission weapons are normally described as "atomic bombs", and that use is sometimes questioned:

From memory, lay people, at least in the US, routinely referred to nuclear weapons as A-Bombs or H-Bombs or generally as "the atomic bomb" from the 1940s to as late as the `60s and `70s . "Atomic power plants" was also fairly normal and creation of the Atomic Energy Commission reflected that usage. The references survive in fiction of the period including Frank Herbert's Dune, in which characters refer to the nuclear stockpiles of the nobility as 'the family atomics.'

Nuclear became more generally used during the debate of the Nuclear Test Ban Treaty(s) which was covered publicly and at length. The AEC's roles were split up in 1974 with the Nuclear Regulatory Commission assuming oversight of the US civilian nuclear industry. Daily reporting on nuclear weapons reduction treaty negotiations between the US and Soviet Union further standardized the usage of nuclear for younger generations. Strategic Arms Limitation Talks began in 1969.

The authors would have encountered the use of 'atomic' in researching 1950s era UFO sighting reports but should have at least noted the changes in terminology over time to provide clarity for modern readers. This suggests they stuck with the dated use of 'atomic' for esthetic reasons not explained in their work.

 

[JMartJr]

This suggests they stuck with the dated use of 'atomic' for esthetic reasons not explained in their work.

Or just were not aware that the usage had shifted a bit.

 

[Todd Feinman]

Nuclear became more generally used during the debate of the Nuclear Test Ban Treaty(s) which was covered publicly and at length.

Now we seem to have more "Nucular Weapons", apparently we started manufacturing them around 1943, according to Wikipedia.

 

[jdog]

...in which Grosvenor, Hancock and Porritt write

3.13 UAP activities at atomic weapons tests
Assessment: No Data / No Assessment
The study database contains no reports of UAP sightings in conjunction with atomic tests.

(post #876);


Edited to add: The quote used in #876 being

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 immediately before, during, and after nuclear weapons tests (7). UAP have often been reported at nuclear
power plants and sites involved in nuclear weapons production as well (7,10).

The paper invokes UFO lore in an "it is known" assertion and references Robert Hasting's book of UFO sightings at nuclear facilities as a reason to check for correlations between transients and nuclear tests.

Hastings' approach, however, is largely anecdotal and introduces a selection bias, since there were UFO reports across the U.S. for decades and he's just collecting reports from one type of remote facility known for having guards day and night. It's like writing a book about foul balls landing in the stands at New York Mets games; it doesn't establish a special relationship between the Mets and foul balls, it's just the only place you're looking.

 

[Fritzkquzerk]

The paper invokes UFO lore in an "it is known" assertion and references Robert Hasting's book of UFO sightings at nuclear facilities as a reason to check for correlations between transients and nuclear tests.

Hastings' approach, however, is largely anecdotal and introduces a selection bias, since there were UFO reports across the U.S. for decades and he's just collecting reports from one type of remote facility known for having guards day and night. It's like writing a book about foul balls landing in the stands at New York Mets games; it doesn't establish a special relationship between the Mets and foul balls, it's just the only place you're looking.

Out of topic but I liked Hastings' works.
I don't believe his claims but he writes well.
Especially that one book about his so called "abduction experiences". It surely was psychologically interesting to me.
Regarding the whole "nuclear/Atomic" thing, I wouldn't focus as much on wording.
If the claim Is "UFOs are Aliens Flying over nuclear bases" then there is no real evidence apart from anecdotal elements, but nuclear bases are just what everyone thinks of when you say it.

 

[FatPhil]

The authors frequently use the word "atomic" in the paper, even when clearly referring to what would normally be described as "nuclear" or "thermonuclear" items/ topics. It is as if they're unfamiliar with the subject matter. Only fission weapons are normally described as "atomic bombs", and that use is sometimes questioned:

Weapons whose explosive output is exclusively from fission reactions are commonly referred to as atomic bombs... This has long been noted as something of a misnomer, as their energy comes from the nucleus of the atom...

Wikipedia, "Nuclear weapon" https://en.wikipedia.org/wiki/Nuclear_weapon#Fission_weapons. It's all a bit strange.

Firstly, remember who wrote that wikipedia page: some rando on the internet. Don't confuse "can be used with more precision" with "is always used with more precision".

Atomic energy is the source of nuclear power

https://en.wikipedia.org/wiki/Atomic_energy

Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions.

https://en.wikipedia.org/wiki/Nuclear_power

If you're not working with actual reactors or bombs, "atomic" = "nuclear". The contrast in the coinages was against harnessing the energy of electrons, and both of those words do exactly the same job. And if you are working in that field, then you need to accept that you are using an *argot* that noone else has been sufficiently motivated to adopt. Sorry, botanists, but peanuts are nuts, and raspberries are berries.

 

[MapperGuy]

Firstly, remember who wrote that wikipedia page: some rando on the internet. Don't confuse "can be used with more precision" with "is always used with more precision".

Atomic energy is the source of nuclear power

https://en.wikipedia.org/wiki/Atomic_energy

Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions.

https://en.wikipedia.org/wiki/Nuclear_power

If you're not working with actual reactors or bombs, "atomic" = "nuclear". The contrast in the coinages was against harnessing the energy of electrons, and both of those words do exactly the same job. And if you are working in that field, then you need to accept that you are using an *argot* that noone else has been sufficiently motivated to adopt. Sorry, botanists, but peanuts are nuts, and raspberries are berries.

And some of the people involved are, I believe, not native English speakers. What terms they use for various things may be influenced by what language the grew up speaking and reading. Not an issue that needs much attention, in my opinion.

 

[Ann K]

@flarkey

This paper provides an assessment of indicators associated with Unidentified Anomalous Phenomena (UAP) reports included in the SCU Pattern Recognition Study (Hancock et al., 2023a). The Pattern Recognition study analyzed UAP incidents geographically proximal to US military installations between 1945 and 1975.
..........
The Pattern Recognition Study concluded that intelligent and focused activity was associated with UAP at atomic facilities to a greater degree than conventional non-atomic military facilities.

https://limina.scholasticahq.com/ar...945-1975-united-states-atomic-warfare-complex

If the survey was written up in 2023, why did they stop with data from 1975?

If they concluded that the activity was "intelligent and focused", it seems likely that earthly powers would be interested in nuclear activity, most probably Russians, during the "Cold War" period.

 

[JMartJr]

If the survey was written up in 2023, why did they stop with data from 1975?

This is just me guessing, but...

The number of satellites in orbit has gone up over time... Perhaps by the 1970s the number of manmade objects in orbit was beginning to be large enough to make it hard to spot the presumed aliens among all the Earthly stuff?

Source: https://www.statista.com/chart/24980/space-debris-in-orbit/?


I had wondered if the number of tests was declining by then, so that perhaps the thinking was there was no point in looking for aliens watching our nuke tests any more. But it looks like, if that was the case, data should have been of interest up through the early 1990s...

Source: https://apjjf.org/2022/7/jacobs

 

[John J.]

I had wondered if the number of tests was declining by then, so that perhaps the thinking was there was no point in looking for aliens watching our nuke tests any more.

Grosvenor, Hancock and Porritt (the authors of "UAP Indications Analysis 1945-1975 United States Atomic Warfare Complex") explicitly state they didn't have any data about reports of UFOs associated with nuclear tests at any time, so number of tests might not have been a factor in deciding their timeframe.

Villarroel et al.'s "Transients...", 2025, appears to have a single source for the claim that UFOs had been associated with nuclear tests, R. Hasting's self-published book. I don't think this necessarily has any bearing on their subsequent work, but I think it is interesting that they consider a self-published book by someone with strong beliefs in undemonstrated (and unlikely) phenomena, e.g. ET abductions of humans, as the basis for a hypothesis to be tested.
But V. et al.'s testing of that hypothesis, and their results, stand or fall on their own merits, not their cited possible inspiration.

Incidentally, I'm interested in UFOs and remember lots of odd details of UFO stories (and forget, and probably misremember many others), but I metaphorically raised an eyebrow on reading that V. et al. noticed that two of the POSS-1 images, containing transients, were on taken on two dates associated with the Washington D.C. events of 1952. One or more of the authors probably has a detailed knowledge of UFO lore.

 

[Mick West]

New from BV:

Dear everyone,
Some new and very exciting news from the VASCO team! First, our machine-learning paper has been accepted for publication following peer review and is now in press. In this paper, we used machine learning to address some of the criticism concerning plate defects and remove contaminants from the sample. We demonstrate that all the intriguing correlations become even stronger as the sample becomes cleaner. More on this once the final version is published.

Second, we have two new preprints. In the first, we use Earth-shadow statistics to infer the altitudes of the objects producing the transients. The results suggest that the objects are located approximately 20,000–35,786 km above the Earth's surface, with the upper limit corresponding to geosynchronous altitude. They are clustering near the equator.

We model their properties. The objects have highly reflective surfaces that are small, flat and ranging from a few centimetres to about 3 metres. Their small sizes may partly reflect the transient-search methodology, in which brighter objects were filtered out. We also discuss various toy models that could explain their observed properties, including sudden changes in attitude (direction of the nose).

Third, we use the projected locations of the pre-Sputnik transients to identify geographic hotspots of transients. Intriguingly, Sedona, White Sands/El Paso, Tampico and several other locations emerge. And we find further associations with nuclear weapons tests.

Enjoy these three pieces of news! Read the two new preprints here:

https://arxiv.org/pdf/2609.05105

https://arxiv.org/pdf/2609.09461

Source:

 

[John J.]

New from BV:

Third, we use the projected locations of the pre-Sputnik transients to identify geographic hotspots of transients. Intriguingly, Sedona, White Sands/El Paso, Tampico and several other locations emerge.

I couldn't find any obvious connection between Sedona and nuclear weapons testing or development.
Wikipedia, Sedona, Arizona https://en.wikipedia.org/wiki/Sedona,_Arizona

Maybe the nuclear tests in the 1950s and after in the American southwest feature to some degree in the town's collective memory,
Sedona Monthly, 01 February 2017 says

Located less than 350 miles from peace-loving Sedona, the 1,360-square-mile nuclear weapons testing complex (roughly the size of Rhode Island) was renamed the Nevada National Security Site in 2010.

"Bomb But Not Forgotten", Joe McNeill https://sedonamonthly.com/2017/bomb-forgotten/

But Las Vegas is much closer to the Nevada test sites, almost on a line between Sedona and the southernmost test sites.
At a glance, Los Angeles may be closer than Sedona is. Albuquerque is much closer to the Trinity test site in what later became the White Sands Missile Range (and to Roswell/ Corona).

@MonkeeSage and @NorCal Dave, others have mentioned Ross Coulthart's support of/ involvement with various claims of "orbs"/ "portals" near Sedona, some in connection with psychic Melinda Leslie (e.g. Dave's post #271, Ross Coulthart thread, MonkeeSage's post #101, New Science of UAP Paper thread).

If Villarroel et al. are considering places connected to UFO sightings (or other claims related to UFOs/ alien visitation/ uncorroborated reports of odd phenomena) that are not connected to nuclear-test related activity (as seems to be the case re Sedona) as positive hits, they have a lot to choose from.

In "Transients in the Palomar Observatory Sky Survey (POSS-I) may be associated with nuclear testing and reports of unidentified anomalous phenomena" (2025, https://www.nature.com/articles/s41598-025-21620-3) Villarroel and Bruehl found a correlation between features they identified as transients and UFO reports, using a

...comprehensive database of UAP witness reports (UFOCAT; see Methods).

UFOCAT has been compiled by the Center for UFO Studies, CUFOS https://cufos.org/cufos-publications-databases/ufocat/:

UFOCAT-2023 refers to a computer database of over 300,000 entries. In this total are over 192,000 primary UFO reports.

(My bold). It is possible (meaning I suspect, but do not know) the majority or a disproportionate number of these reports are from the USA (the frequency of UFO reports internationally has been discussed briefly in another thread).

In their 2025 study, Villarroel and Bruehl cite Hancock and Porritt's "UAP Indications Analysis 1945-1975 United States Atomic Warfare Complex" (2025, https://limina.scholasticahq.com/ar...945-1975-united-states-atomic-warfare-complex); it is unclear what exact sources Hancock and Porritt used, perhaps not anything as comprehensive as the large UFOCAT database.
However, those authors write

3.13 UAP activities at atomic weapons tests
Assessment: No Data / No Assessment
The study database contains no reports of UAP sightings in conjunction with atomic tests.

Considering their subject matter, if there were well-known UFO reports connected to nuclear tests pre-1975 it might be surprising that Hancock and Porritt didn't find any.
_____________________________________________________________________________________________________________________________________________________

Off-topic: I don't know if the UFOCAT database simply records all UFO reports or if there is any filtering of less-credible cases.
Lots of cases from CUFOS's HUMCAT index, which records reports of aliens, are viewable on the CUFOS website (up to 1977), https://cufos.org/resources/ufo-catalogues/. Some seem very implausible, others have contexts which suggest figures seen during parasomnias like sleep paralysis. No assessment accompanies the entries (as far as I've seen).

I liked this one, though it might not be convincing evidence of extraterrestrial visitation, https://cufos.org/PDFs/HUMCAT/HUMCAT_Index_1950-1951.pdf.
The investigator was a Kenneth Arnold, it would be interesting to know if he is the Kenneth Arnold of 1947 Mount Rainier sighting fame: