Within Tombaugh Sighting
Could Atmosphere Explain Tombaugh's Lights?
Possible atmospheric and optical effects offer natural explanations for how a structured formation of lights could appear briefly in the sky.
On this page
- Optical effects in the atmosphere
- Tombaugh's preferred explanation
- Why the cause remains uncertain
Page outline Jump by section
Introduction
The atmospheric explanation for Clyde Tombaugh’s 1949 lights does not depend on proving that the sighting was a mistake. Instead, it asks whether a rare interaction between light and the atmosphere could have produced the brief appearance of a structured formation. Tombaugh himself, despite being the astronomer who discovered Pluto, favoured this type of explanation over an extraterrestrial craft, suggesting that a temperature inversion or other optical boundary in the atmosphere could have reflected or redirected light in an unusual way.[Wikipedia]WikipediaClyde TombaughClyde Tombaugh
The key idea is that the lights may not have been physical objects travelling through the sky. They could have been an optical image created when light passed through layers of air with different temperatures and densities. Such conditions can bend, distort, duplicate, compress, or displace images, sometimes creating effects that appear highly organised to an observer.[ScienceDirect]sciencedirect.comScienceDirect Atmospheric OpticsAtmospheric Optics - an overview | ScienceDirect Topics… For Tombaugh’s sighting, this remains an explanation rather than a demonstrated solution: the observation lasted only seconds, and no meteorological measurements were recorded at the exact time and location.
Optical effects in the atmosphere
How a temperature inversion could create unusual lights
A temperature inversion occurs when warmer air lies above cooler air, reversing the normal pattern in which air generally becomes colder with altitude. These layers can create sharp changes in air density and therefore in the way light travels. Under suitable conditions, light rays can bend along curved paths rather than moving in a straight line, producing mirages and other displaced images.[Met Office]weather.metoffice.gov.ukMet Office What is a temperature inversion?Met OfficeWhat is a temperature inversion? - Met Office…
This mechanism is important for Tombaugh’s report because he described the lights as a formation of faint bluish-green rectangles that changed appearance as they moved away from the overhead position. According to accounts of his observation, the formation became narrower, the individual shapes appeared foreshortened, and the brightness faded as it moved toward the southern horizon. Tombaugh later argued that this behaviour resembled the kind of distortion expected from an atmospheric optical boundary rather than from a solid object.[Wikipedia]WikipediaClyde TombaughClyde Tombaugh
An atmospheric layer can act somewhat like a weak lens or mirror. It does not create light by itself, but it can redirect existing light sources, including distant artificial lights, reflections, or other luminous sources, into unexpected positions. The resulting image may appear detached from its true source, making it difficult for an observer to identify what produced it.[ScienceDirect]sciencedirect.comScienceDirect Atmospheric OpticsAtmospheric Optics - an overview | ScienceDirect Topics…
Why the shape of the lights matters
The unusual feature of the Tombaugh sighting was not simply that lights were seen, but that they appeared arranged in a geometric pattern. Atmospheric explanations therefore need to account for the apparent rectangular formation, not merely the colour or brightness.
Optical mirages are capable of producing distorted and repeated images rather than simple glowing patches. The World Meteorological Organization notes that mirages can produce images that are displaced, enlarged, reduced, inverted, or multiple, depending on atmospheric conditions.
International Cloud Atlas
In principle, a structured source of light could retain some of its arrangement while being altered by refraction, creating an appearance that seems like a formation of separate objects.
The difficulty is that the exact source of the light in Tombaugh’s case is unknown. A complete atmospheric explanation would need to identify what light was being refracted and how the optical conditions produced the observed colour, spacing, and movement. Without photographs, instruments, or atmospheric records from the moment of the sighting, that reconstruction cannot be confirmed.
Tombaugh’s preferred explanation Why the witness himself favoured atmospheric optics[sciencedirect.com]sciencedirect.comScienceDirect Atmospheric OpticsAtmospheric Optics - an overview | ScienceDirect Topics…
Tombaugh’s later comments are significant because they show that the leading atmospheric interpretation did not originate only from outside sceptics. He did not regard the event as proof of a spacecraft. Instead, he considered a natural optical phenomenon more plausible, specifically mentioning the possibility of an atmospheric inversion or reflective boundary.[Wikipedia]WikipediaClyde TombaughClyde Tombaugh
His reasoning came from the behaviour of the phenomenon. Tombaugh noted that the lights were faint, appeared briefly, and faded in a way he associated with a changing viewing angle through an optical layer. He considered the rarity of such conditions a better explanation than an extraordinary physical visitor.[Wikipedia]WikipediaClyde TombaughClyde Tombaugh
This interpretation also reflects the distinction between astronomical expertise and atmospheric observation. Tombaugh was highly skilled at recognising celestial objects, but the event he described was not a conventional astronomical sighting. It involved light passing through the atmosphere, an area where unusual combinations of temperature, density, and viewing geometry can create effects that are unfamiliar even to experienced sky watchers.[NCAS Files]files.ncas.orgFiles Condon Report, Sec VI, Chapter 4: Optical MirageNCAS FilesCondon Report, Sec VI, Chapter 4: Optical Mirage…
The connection with other unusual light formations
The resemblance between Tombaugh’s report and other mid-century light formations contributed to later discussion of atmospheric explanations. Tombaugh himself compared the appearance to the later Lubbock Lights, another case involving bluish-green lights in formation.[Think About It Docs]thinkaboutitdocs.comastronomer clyde tombaugh ufo sighting astronomer who discovered plutoThink About It Docs1949: The Clyde Tombaugh Sighting — Las Cruces, New MexicoApril 8, 2013…
However, similarity does not establish a common cause. A formation of lights can arise from several possibilities, including optical effects, reflections, or unidentified physical sources. The value of the atmospheric hypothesis is that it offers a mechanism for producing a structured appearance without requiring the lights themselves to be a structured craft.
Why the cause remains uncertain
The strongest argument for an atmospheric explanation is that the sighting contains features that optical phenomena can potentially reproduce: rapid appearance and disappearance, changes in shape, fading with viewing angle, and the involvement of light rather than a clearly visible solid object. Atmospheric optics is a well-established field, and temperature gradients are known to create dramatic distortions of distant images.
International Cloud Atlas
The main limitation is the lack of direct evidence. No photograph, radar record, physical trace, or weather data from the exact moment of the observation can test the proposed mechanism. The explanation remains a reconstruction based on the visual description rather than a verified identification.[Wikipedia]WikipediaClyde TombaughClyde Tombaugh
The case therefore illustrates a broader challenge in analysing rare aerial observations. A credible witness can provide a careful description, yet the final interpretation may remain uncertain when the event is brief and unrepeatable. In Tombaugh’s case, atmospheric optics offers a scientifically plausible pathway for explaining how a strange formation of lights could appear, but the available evidence does not allow the precise optical process to be proven.
Amazon book picks
Further Reading
Books and field guides related to Could Atmosphere Explain Tombaugh's Lights?. Use these as the next step if you want deeper reading beyond the article.
UFOs
NEW YORK TIMES BESTSELLER • Impeccably researched, this riveting journalistic investigation separates fact from fiction, and documents th...
The Nature of Light and Colour in the Open Air
A highly engaging study of mirages, illusions of multiple moons, the fata morgana, colored shadows and scores of other phenomena. "Pure p...
The Demon-Haunted World: Science as a Candle in the Dark
Are we on the brink of a new Dark Age of irrationality and superstition? In this book, the writer shows how scientific thinking is necess...
eBay marketplace picks
Marketplace Samples
Live-tested eBay searches with available results related to this page.
Selected fromastronomy poster oneBay.co.uk.
Endnotes
1.
Source: Wikipedia
Title: Clyde Tombaugh
Link:https://en.wikipedia.org/wiki/Clyde_Tombaugh
2.
Source: sciencedirect.com
Title: ScienceDirect Atmospheric Optics
Link:https://www.sciencedirect.com/topics/physics-and-astronomy/atmospheric-optics
Source snippet
Atmospheric Optics - an overview | ScienceDirect Topics...
3.
Source: files.ncas.org
Title: Files Condon Report, Sec VI, Chapter 4: Optical Mirage
Link:https://files.ncas.org/condon/text/s6chap04.htm
Source snippet
NCAS FilesCondon Report, Sec VI, Chapter 4: Optical Mirage...
4.
Source: weather.com
Title: 2026 01 13 weather words mirage
Link:https://weather.com/science/weather-explainers/news/2026-01-13-weather-words-mirage
Source snippet
Weather Words: Mirage | Weather.comJanuary 26, 2026 — WEATHER WORDS: MIRAGE A MIRAGE IS AN OPTICAL ILLUSION CREATED WHEN SHARP TEMPERATUR...
Published: January 26, 2026
5.
Source: weather.metoffice.gov.uk
Title: Met Office What is a temperature inversion?
Link:https://weather.metoffice.gov.uk/learn-about/weather/types-of-weather/temperature/temperature-inversion
Source snippet
Met OfficeWhat is a temperature inversion? - Met Office...
6.
Source: thinkaboutitdocs.com
Title: astronomer clyde tombaugh ufo sighting astronomer who discovered pluto
Link:https://thinkaboutitdocs.com/astronomer-clyde-tombaugh-ufo-sighting-astronomer-who-discovered-pluto/
Source snippet
Think About It Docs1949: The Clyde Tombaugh Sighting — Las Cruces, New MexicoApril 8, 2013...
Published: April 8, 2013
7.
Source: justapedia.org
Title: Clyde Tombaugh
Link:https://justapedia.org/wiki/Clyde_Tombaugh
9.
Source: hyperphysics.phy-astr.gsu.edu
Link:https://www.hyperphysics.phy-astr.gsu.edu/hbase/atmos/mirage.html
10.
Source: lacasadelaarquitectura.es
Title: Clyde Tombaugh
Link:https://lacasadelaarquitectura.es/en/resource/clyde-tombaugh/7a162973-7be9-4d5d-b0d0-05e0a8798500
11.
Source: scientificlib.com
Title: Clyde Tombaugh
Link:https://www.scientificlib.com/en/Astronomy/Biographies/ClydeTombaugh.html
Additional References
12.
Source: nationalgeographic.com
Link:https://www.nationalgeographic.com/science/article/what-are-noctilucent-clouds
Source snippet
June 11, 2026 — HOW TO SPOT THESE ELECTRIC-BLUE CLOUDS THAT FORM AT THE EDGE OF SPACE Forming 50 miles above Earth's surface, noctilucent...
Published: June 11, 2026
13.
Source: engr.colostate.edu
Title: Their color patterns are ordered, in approximately horizont
Link:https://www.engr.colostate.edu/~hillger/optical-phenomena.htm
Source snippet
Optical Phenomena (except Rainbows and Auroras)May 7, 2026 — CIRCUMHORIZONTAL ARC Circumhorizontal arcs are visually similar in some ways...
Published: May 7, 2026
14.
Source: scribd.com
Link:https://www.scribd.com/document/427182434/Ufo
Source snippet
UFOs and Government: A Historical Inquiry | PDF | Unidentified Flying Object | Ufology...
15.
Source: youtube.com
Title: The Physics of Mirrored Horizons: Why the Atmosphere Behaves Like a Lens
Link:https://www.youtube.com/watch?v=8yCBqjLyQ8g
Source snippet
What is Superior Mirage? Why the Ship looks Floating?...
16.
Source: wikiland.org
Link:https://wikiland.org/fr/Clyde_Tombaugh
17.
Source: gutenberg.org
Link:https://www.gutenberg.org/files/66639/66639-h/66639-h.htm
18.
Source: dl1.en-us.nina.az
Link:https://www.dl1.en-us.nina.az/Clyde_Tombaugh.html
19.
Source: youtube.com
Title: What is Superior Mirage? Why the Ship looks Floating?
Link:https://www.youtube.com/watch?v=Uy9adgmxQ_A
Source snippet
Fata Morgana—Boats That Float In The Air...
20.
Source: infinityexplorers.com
Link:https://www.infinityexplorers.com/clyde-tombaugh-pluto/
21.
Source: nature.com
Title: Temperature Inversion by Convective Cooling | Nature
Link:https://www.nature.com/articles/164071a0