Within Bonilla Observation
Was a Comet Behind the 1883 Images?
A modern proposal suggests the objects may have been fragments of a disintegrating comet passing unusually close to Earth.
On this page
- The 2011 comet fragment proposal
- Astronomical clues and calculations
- Why the theory remains debated
Page outline Jump by section
Introduction
The comet fragment hypothesis is the most ambitious modern reinterpretation of the José A. y Bonilla photograph of 1883. It proposes that the dark shapes recorded at the Zacatecas Observatory were not unknown aircraft or ordinary nearby objects, but pieces of a comet that had broken apart and passed extremely close to Earth. The idea emerged in 2011 from researchers at the National Autonomous University of Mexico, who used Bonilla’s recorded timings, apparent motion, and descriptions of the objects to model a possible fragmented comet encounter.[arXiv]arxiv.orgInterpretation of the observations made in 1883 in Zacatecas (Mexico): A fragmented Comet that nearly hits the EarthOctober 12, 2011…
The proposal changed the way the photographs were discussed because it offered a natural astronomical explanation that could account for several unusual features of the observation: the large number of objects, their apparent movement across the Sun, their reported fuzzy appearance, and the dark trails described by Bonilla. However, the comet interpretation remains a debated reconstruction rather than an established identification. The available evidence supports the possibility of a fragmented comet, but it does not conclusively rule out other explanations such as objects close to the telescope.[Wikipedia]WikipediaBonilla observationBonilla observation
The 2011 comet fragment proposal
The modern comet explanation was developed in the 2011 paper Interpretation of the observations made in 1883 in Zacatecas (Mexico): A fragmented Comet that nearly hits the Earth. Authors Héctor Javier Durand Manterola, María de la Paz Ramos Lara, and Guadalupe Cordero revisited Bonilla’s original observations with modern astronomical calculations. Their central argument was that a fragmented comet passing close to Earth could produce the kind of apparent solar transits recorded at Zacatecas.[arXiv]arxiv.orgInterpretation of the observations made in 1883 in Zacatecas (Mexico): A fragmented Comet that nearly hits the EarthOctober 12, 2011…
The researchers focused on several details from Bonilla’s report. He observed hundreds of objects crossing the Sun on 12 and 13 August 1883 and recorded many of them photographically. The objects were described as indistinct or cloud-like, and some were reported to have trails. A swarm of comet fragments could naturally produce multiple dark silhouettes rather than a single solid object, especially if the fragments were surrounded by dust and gas released during breakup.[Wikipedia]WikipediaBonilla observationBonilla observation
The proposal also attempted to explain why the event was apparently limited to Bonilla’s location rather than being widely reported. The researchers argued that the geometry of a very close pass, combined with parallax — the apparent shift of an object when viewed from different locations — could mean that only observers in a narrow region would have seen the fragments crossing the Sun in the same way.[Wikipedia]WikipediaBonilla observationBonilla observation
Astronomical clues and calculations
The strongest part of the comet hypothesis comes from its attempt to convert Bonilla’s visual record into physical estimates. By analysing the apparent size and movement of the objects across the solar disc, the 2011 study estimated that the fragments may have passed between roughly 538 kilometres and 8,062 kilometres above Earth’s surface. The estimated fragment widths ranged from tens to hundreds of metres, with the researchers proposing that the original comet could have had a mass comparable in scale to a small fraction of, or several times, the mass of Halley’s Comet depending on the assumptions used.[arXiv]arxiv.orgInterpretation of the observations made in 1883 in Zacatecas (Mexico): A fragmented Comet that nearly hits the EarthOctober 12, 2011…
The calculations were based on interpreting Bonilla’s observations as a close atmospheric-scale encounter rather than a distant astronomical transit. If the fragments had really passed at such distances, the event would have been an unusually close cometary flyby. Modern astronomy has documented that comet nuclei can break apart into multiple pieces, producing fragment clouds and dust structures, making the general mechanism physically plausible.[arXiv]arxiv.orgarXiv The catastrophic fragmentation of Comet 332P (Ikeya-MurakamiThe catastrophic fragmentation of Comet 332P (Ikeya-Murakami)February 24, 2016…
One reason the hypothesis attracted attention was the dramatic implication: a fragmented comet passing close to Earth would represent a major planetary hazard scenario. The 2011 authors estimated that a direct collision with many large fragments could have produced consequences comparable in scale to multiple Tunguska-like impacts. Those estimates, however, depend heavily on the assumed fragment sizes, composition, and trajectory, all of which are reconstructed rather than directly measured.[Phys.org]phys.orgOpen source on phys.org.
The comet interpretation also gives a different meaning to the photographs themselves. Instead of being images of unexplained “objects” in the modern UFO sense, they would represent a rare astronomical event captured with early photographic technology: the passage of a fragmenting natural body through Earth’s neighbourhood. The photographs would therefore remain historically important while having a conventional astronomical explanation.
Why the theory remains debated
The main challenge for the comet explanation is that it requires several uncertain assumptions to align. Bonilla’s photographs and notes provide evidence that something crossed the telescope’s view, but they do not provide direct measurements of distance, size, speed, or composition. The comet model must infer those values from limited 19th-century observations.[Wikipedia]WikipediaBonilla observationBonilla observation
Sceptics have pointed out that the original astronomical discussion of the event did not identify a comet. When Bonilla’s report appeared in L’Astronomie in 1886, the explanation considered more likely at the time was that nearby objects such as birds or insects had passed close to the telescope and appeared as silhouettes against the bright Sun. This interpretation explains why the event was not widely observed by other astronomers, although it also has difficulties explaining every detail of Bonilla’s description.[Wikipedia]WikipediaBonilla observationBonilla observation
Astronomer Phil Plait, writing in Discover Magazine after the 2011 proposal, argued that the comet scenario was intriguing but that the evidence was not sufficient to establish such an extraordinary near miss. His criticism focused on the lack of independent confirmation and the large number of assumptions required to reconstruct the encounter.[Discover Magazine]discovermagazine.comDiscover MagazineDid a fragmenting comet nearly hit the Earth in 1883? Color me very skeptical | Discover Magazine…
The debate illustrates why the Bonilla photographs remain unusual in the history of unexplained observations. The images provide genuine documentary evidence of an event, but identifying the cause requires interpretation. The comet fragment hypothesis is valuable because it demonstrates how modern astronomy can revisit historical records with new tools, while also showing the limits of reconstructing an event more than a century after it occurred.
The most balanced view is that a fragmented comet is a scientifically possible explanation that fits some of the reported characteristics of the 1883 observation, but it has not replaced all competing interpretations. The Bonilla photographs remain a case where better modelling has narrowed the possibilities without producing a final answer.
Amazon book picks
Further Reading
Books and field guides related to Was a Comet Behind the 1883 Images?. Use these as the next step if you want deeper reading beyond the article.
Comet
Comet begins with a breathtaking journey through space astride a comet. Pulitzer Prize-winning astronomer Carl Sagan, author of Cosmos an...
Cosmic Perspective, The, Loose-Leaf Edition
NOTE: This loose-leaf, three-hole punched version of the textbook gives you the flexibility to take only what you need to class and add y...
The Planets
After 'LONGITUDE' and 'GALILEO'S DAUGHTER', Dava Sobel tells the human story of the nine planets of our solar system.
The Cosmic Perspective
First published 2014. Subjects: Astronomy, Astronomy, study and teaching, Textbooks, Study and teaching (Higher).
eBay marketplace picks
Marketplace Samples
Live-tested eBay searches with available results related to this page.
Selected fromcomet model oneBay.co.uk.
Endnotes
1.
Source: arxiv.org
Link:https://arxiv.org/abs/1110.2798
Source snippet
Interpretation of the observations made in 1883 in Zacatecas (Mexico): A fragmented Comet that nearly hits the EarthOctober 12, 2011...
Published: October 12, 2011
2.
Source: Wikipedia
Title: Bonilla observation
Link:https://en.wikipedia.org/wiki/Bonilla_observation
3.
Source: phys.org
Link:https://phys.org/news/2011-10-mexican-astronomers-bonilla-sighting-comet.html
4.
Source: arxiv.org
Title: arXiv The catastrophic fragmentation of Comet 332P (Ikeya-Murakami)
Link:https://arxiv.org/abs/1602.07569
Source snippet
The catastrophic fragmentation of Comet 332P (Ikeya-Murakami)February 24, 2016...
Published: February 24, 2016
5.
Source: arxiv.org
Link:https://arxiv.org/abs/1410.0493
Source snippet
Comet C/2011 J2 (Linear): Fragmentation and physical properties of the two nuclei...
6.
Source: phys.org
Link:https://phys.org/news/2011-10-mexican-astronomers-bonilla-sighting-comet.amp
7.
Source: discovermagazine.com
Link:https://www.discovermagazine.com/did-a-fragmenting-comet-nearly-hit-the-earth-in-1883-color-me-very-skeptical-23066
Source snippet
Discover MagazineDid a fragmenting comet nearly hit the Earth in 1883? Color me very skeptical | Discover Magazine...
Additional References
8.
Source: thinkaboutitdocs.com
Title: 1883 zacatecas observatory mexico sighting
Link:https://www.thinkaboutitdocs.com/1883-zacatecas-observatory-mexico-sighting/
Source snippet
1883: José Bonilla's Zacatecas Observatory Solar Transit — 300+ Objects Photographed on Wet Plates, Geese Hypothesis Examined | Think Abo...
9.
Source: monkeyandelf.com
Title: a massive comet almost annihilated humanity in 1883
Link:https://www.monkeyandelf.com/a-massive-comet-almost-annihilated-humanity-in-1883/
Source snippet
Monkey and ElfThe 1883 Bonilla Observation: A UNAM Team Calculated a Fragmented Comet Passed Within 8,000 Kilometers of Earth...
10.
Source: youtube.com
Title: Top 10 Times the World should have ENDED!! List of crazy world events!
Link:https://www.youtube.com/watch?v=k6JP-ghEn88
Source snippet
Edward Guimont, "Shadow of the Comet: Celestial Speculation in Twain's Lifetime"...
11.
Source: youtube.com
Link:https://www.youtube.com/watch?v=g0UQC59toHs
Source snippet
Top 10 Times the World should have ENDED!! List of crazy world events...
12.
Source: nature.com
Title: Ocean-like water in the Jupiter-family comet 103P/Hartley 2 | Nature
Link:https://www.nature.com/articles/nature10519
13.
Source: researchgate.net
Link:https://www.researchgate.net/publication/50855849_HUBBLE_SPACE_TELESCOPE_OBSERVATIONS_OF_MAIN-BELT_COMET_596_SCHEILA
14.
Source: researchgate.net
Link:https://www.researchgate.net/publication/51945342_Interpretation_of_the_observations_made_in_1883_in_Zacatecas_Mexico_Afragmented_Comet_that_nearly_hits_the_Earth
15.
Source: researchgate.net
Link:https://www.researchgate.net/figure/Geometry-of-Bonillas-observation-Z-Zacatecas-M-Mexico-City-or-Puebla-and-O-is-the_fig1_51945342
16.
Source: spaceref.com
Link:https://spaceref.com/status-report/interpretation-of-the-observations-made-in-1883-in-zacatecas-a-fragmented-comet-that-nearly-hits-the-earth/
17.
Source: spacesafetymagazine.com
Link:https://www.spacesafetymagazine.com/space-hazards/asteroid-hitting-earth/reanalysis-observations-recorded-1883-zacatecas-mexico-suggest-fragments-billion-ton-comet-close-earth/