Within Mirages
Why Can a Ship Appear to Float?
A superior mirage can lift a distant ship above the visible sea, creating a convincing model for some apparent airborne-object reports.
On this page
- What happened in the Cornwall floating ship photographs
- How a temperature inversion lifts the apparent image
- Why the same geometry matters for UFO reports
Page outline Jump by section
Introduction
A distant ship can appear to be an airborne object when atmospheric refraction alters its position or shape near the horizon. The best-known modern example is the striking set of photographs taken near Falmouth, Cornwall, in early 2021, showing a tanker apparently suspended above the sea. The images were widely identified as a superior mirage, produced when cold air near the water lay beneath warmer air and bent light from the distant vessel.[The Guardian]theguardian.comThe GuardianWalker 'stunned' to see ship hovering high above sea off Cornwall | Science | The GuardianMarch 5, 2021…
The case is useful for understanding some UFO and UAP reports because the source is not mysterious: there really is a ship in the distance. What becomes misleading is its apparent relationship to the horizon. Genuine superior mirages can raise, stretch, invert and duplicate ships, sometimes making them look remarkably unlike ordinary vessels. But the Cornwall photographs also carry an important caution: their precise optical explanation has been disputed. They therefore illustrate both the power of horizon effects and the danger of assigning a specific mirage mechanism from appearance alone.[International Cloud Atlas]cloudatlas.wmo.intInternational Cloud Atlas Mirage | International Cloud AtlasInternational Cloud Atlas Mirage | International Cloud Atlas
What happened in the Cornwall photographs?
In March 2021, photographs by David Morris attracted international attention after he saw a large tanker apparently hovering above the sea while looking out from Gillan, near Falmouth. The vessel itself remained recognisable, but a conspicuous band apparently separated its hull from the visible water. Morris described being stunned by the sight. The Guardian, Independent and CBS News subsequently reported the phenomenon as a superior mirage, citing meteorologist David Braine.[theguardian.com]theguardian.comThe GuardianWalker 'stunned' to see ship hovering high above sea off Cornwall | Science | The GuardianMarch 5, 2021…
The interpretation was physically plausible in general terms. A temperature inversion reverses the atmosphere’s usual pattern: instead of temperature simply falling with height, a layer of warmer air sits above cooler air. The Met Office describes such inversions as layers in which temperature increases with height, with cooler air trapped underneath warmer air. Over a cold sea, that arrangement can provide exactly the refractive environment associated with superior mirages.[Met Office]weather.metoffice.gov.ukMet Office What is a temperature inversion?Met OfficeWhat is a temperature inversion? - Met Office…
Braine’s explanation was that cold air lay close to the relatively cold sea with warmer air above. Because the colder air was denser and had a slightly higher refractive index, light from the distant ship could curve downwards on its route towards an observer on the coast. The observer, effectively extrapolating those arriving rays backwards in straight lines, would perceive the source higher than its true position.[The Guardian]theguardian.comThe GuardianWalker 'stunned' to see ship hovering high above sea off Cornwall | Science | The GuardianMarch 5, 2021…
The timing made the photographs especially memorable. A second set of apparently hovering vessels was photographed off Dorset less than two weeks later, including the cruise ship Jewel of the Seas. The Guardian again attributed the appearance to cold air over the sea beneath warmer air. With numerous cruise ships anchored off southern England during the pandemic, large and readily identifiable targets happened to be available near the horizon when favourable optical conditions occurred.[The Guardian]theguardian.comThe GuardianSecond vessel in two weeks appears to float above UK waters | Science | The GuardianMarch 18, 2021…
That combination matters. These were not vague points of light whose identity had to be guessed. They were large conventional vessels that looked, at first glance, as though they occupied physically impossible positions. The photographs therefore offer an unusually intuitive demonstration of how an observation can be authentic while the observer’s natural interpretation of its geometry is wrong.
How can an inversion lift the apparent image?
A superior mirage does not literally pick up an object’s image and move it like a photograph being dragged upwards. Light from different parts of a distant object travels through slightly different portions of an atmosphere whose density and refractive index change with height. The resulting ray paths can curve by different amounts. The World Meteorological Organization’s International Cloud Atlas notes that mirages can consequently produce single or multiple images that are upright or inverted and vertically enlarged or reduced; objects may also appear at substantially different angles above the horizon from their true positions.[International Cloud Atlas]cloudatlas.wmo.intInternational Cloud Atlas Mirage | International Cloud AtlasInternational Cloud Atlas Mirage | International Cloud Atlas
Ships provide particularly clear demonstrations because they have recognisable vertical structures — hulls, masts, funnels and superstructures — against a comparatively simple sea-and-sky background. Atmospheric Optics documents superior ship mirages in which an inverted vessel appears above the ordinary image and, under more complicated conditions, another upright image appears higher still. The exact result depends on the vertical temperature profile rather than merely on the existence of an inversion.[Atmospheric Optics]atoptics.org.ukAtmospheric Optics OPODAtmospheric OpticsOPOD - 4 ship superior mirageMarch 25, 2012…
This distinction separates several effects that can look superficially similar. Looming primarily changes apparent position, allowing a distant object to appear higher than normal or even bringing something geometrically below the horizon into sight. Stronger or more complicated differential refraction can stretch, squash, invert or multiply parts of an image. A particularly elaborate superior mirage can produce the shifting, stacked distortions commonly associated with a Fata Morgana.[International Cloud Atlas]cloudatlas.wmo.intInternational Cloud Atlas Mirage | International Cloud AtlasInternational Cloud Atlas Mirage | International Cloud Atlas
Historical marine observations show how dramatic this can become. The technical chapter on optical mirages in the Condon UFO study reproduced maritime observations in which ships underwent marked vertical extension and distortion. In another 1955 observation near Cape Town, a tanker about eight miles away appeared so distorted that its funnel became greatly elongated and seemed taller than its masts. Such examples are valuable because the target’s underlying identity was known: atmospheric propagation had transformed an ordinary ship into an unfamiliar-looking object.[NCAS Files]files.ncas.orgFiles Condon Report, Sec VI, Chapter 4: Optical MirageNCAS FilesCondon Report, Sec VI, Chapter 4: Optical Mirage…
There is also an important geometrical constraint. The Condon study emphasised that a steep temperature gradient by itself is not sufficient. Light must encounter the strongly refracting layer at a shallow, grazing angle. Superior mirages are consequently most relevant to objects lying close to the apparent horizon, rather than objects genuinely high overhead.[NCAS Files]files.ncas.orgFiles Condon Report, Sec VI, Chapter 4: Optical MirageNCAS FilesCondon Report, Sec VI, Chapter 4: Optical Mirage…
Was the Cornwall ship definitely a superior mirage?
The widely reported answer was yes, but the photographs deserve more careful treatment than their viral captions usually received.
The initial reporting was not completely uniform. ITV’s West Country report on 4 March 2021 described a simpler visual explanation involving the similar colouring of distant sea and sky, which could make the water around the ship difficult to distinguish and create the appearance of empty sky beneath it. Subsequent national and international reports instead presented Braine’s superior-mirage explanation.[ITVX]itv.comXMan left shocked as large ship appears to float in the sky | ITV News West CountryMarch 4, 2021…
Independent discussion of the photographs has also questioned whether their particular appearance is what a superior mirage should produce. A Physics Stack Exchange analysis, for example, pointed out the conspicuous difficulty: the ship looks comparatively undistorted, while the apparent gap underneath it seems to be sky or sky-coloured sea. One proposed alternative is that the misleading feature is therefore the background beneath the vessel rather than a dramatically displaced image of the vessel itself.[Physics Stack Exchange]physics.stackexchange.comPhysics Stack ExchangeopticsPhysics Stack Exchangeoptics
That criticism should not be confused with a claim that superior ship mirages are doubtful. They are well documented. Atmospheric Optics photographs show ships accompanied by clearly inverted and repeated images, while the World Meteorological Organization explicitly recognises superior mirages over cold sea surfaces. The issue is narrower: whether this particular famous Cornwall photograph demonstrates precisely the mechanism that popular reports assigned to it.[Atmospheric Optics]atoptics.org.ukAtmospheric Optics OPODAtmospheric OpticsOPOD - 4 ship superior mirageMarch 25, 2012…
This makes the Cornwall case more instructive, not less. A photograph can establish that a ship looked astonishingly airborne without, by itself, establishing which atmospheric or contrast effect produced the apparent separation from the water. For UFO analysis, that distinction is fundamental. Identifying an ordinary source is one question; reconstructing the exact optical path that made it look extraordinary is another.
Why does the same geometry matter for UFO reports?
A ship distorted near the horizon is a useful analogue for a particular class of UFO or UAP observation because an observer normally judges an object’s altitude partly from its relationship to the horizon and surrounding landscape. Once refraction corrupts those reference points, a surface object can acquire the visual characteristics of something airborne.
Three changes are especially important. First, apparent elevation can detach an object from the surface with which it would normally be associated. Second, distortion can remove familiar proportions: a funnel, mast or hull may stretch or compress until the silhouette no longer immediately reads as a ship. Third, multiple or inverted images can produce apparent structures that do not correspond to any single physical object.[Atmospheric Optics]atoptics.org.ukAtmospheric Optics OPODAtmospheric OpticsOPOD - 4 ship superior mirageMarch 25, 2012…
The Condon study’s UFO analysis contains historical cases where precisely this possibility was considered. Its optical and radar chapter discusses reports in which superior mirages of ships beyond the normal horizon were regarded as likely components of unusual-object sightings. Elsewhere, investigators considered atmospheric miraging because reported objects remained close to the observer’s horizontal plane and changed shape in ways consistent with strong optical distortion. The report nevertheless stressed that a proposed mirage had to satisfy both the viewing geometry and the meteorological conditions.[NCAS Files]files.ncas.orgFiles Condon Report, Sec III, Chapter 5: Optical & Radar AnalysisFiles Condon Report, Sec III, Chapter 5: Optical & Radar Analysis
That gives the floating-ship example a more useful lesson than simply saying that “UFOs can be mirages”. A credible mirage hypothesis makes testable predictions. The object should generally be close to the horizon or refracting layer; a suitable temperature structure should be possible; a distant source should exist in approximately the required direction; and the observed displacement or distortion should be compatible with atmospheric refraction. Merely finding an inversion somewhere in the weather record is not enough.[NCAS Files]files.ncas.orgFiles Condon Report, Sec VI, Chapter 4: Optical MirageNCAS FilesCondon Report, Sec VI, Chapter 4: Optical Mirage…
Conversely, an apparently airborne object that is well above the horizon, seen through ordinary atmospheric conditions and tracked from several geometrically useful viewpoints would be a much poorer candidate for this explanation. Superior mirages are powerful precisely because their effects can be dramatic within a restricted optical geometry, not because they can arbitrarily relocate anything anywhere in the sky.
The strongest lesson from a “floating” ship
The most important feature of these photographs is that the observer need not hallucinate, exaggerate or fabricate anything. A camera can record the same extraordinary-looking scene. Atmospheric refraction and horizon contrast are physical effects acting on the light before it reaches either an eye or a sensor.
Well-documented superior mirages provide the strongest version of the demonstration. Ships have been photographed with inverted copies above them, with additional upright images, and with funnels and hulls stretched into shapes that scarcely resemble their ordinary proportions. The International Cloud Atlas confirms that distant objects in mirages can be displaced, multiplied, inverted and vertically distorted, while specialised ship observations show those effects occurring in practice.[wmo.int]cloudatlas.wmo.intInternational Cloud Atlas Mirage | International Cloud AtlasInternational Cloud Atlas Mirage | International Cloud Atlas
The Cornwall photographs add a useful evidential warning. Their airborne appearance is obvious, but the exact mechanism behind that appearance has attracted competing interpretations. For an investigation of an unidentified aerial observation, that is precisely the right distinction to preserve: demonstrating that known atmospheric optics can create convincing “objects in the sky” does not justify labelling every puzzling horizon photograph a superior mirage.
Instead, floating ships establish a narrower and stronger point. A familiar object at sea level can genuinely be photographed in a configuration that makes it appear airborne, and strong atmospheric refraction can transform distant ships even more radically. When a UFO or UAP report originates close to a sea horizon, particularly under inversion conditions, investigators therefore have good reason to test for ships and other surface sources before inferring that the reported object’s apparent altitude reflects its true physical position.[NCAS Files]files.ncas.orgFiles Condon Report, Sec VI, Chapter 4: Optical MirageNCAS FilesCondon Report, Sec VI, Chapter 4: Optical Mirage…
Amazon book picks
Further Reading
Books and field guides related to Why Can a Ship Appear to Float?. Use these as the next step if you want deeper reading beyond the article.
Color and Light in Nature
We live in a world of optical marvels - from the commonplace but beautiful rainbow, to the rare and eerie superior mirage. But how many o...
Light and Color in the Outdoors
All of science springs from the observation of nature. In this classic book, the late Professor Minnaert accompanies the reader on a tour...
The Cloudspotter's Guide
Discusses the history, types, and cultural fascination with clouds and explains what they mean in terms of climate and weather.
Rainbows, Halos, and Glories
First published 1980. Subjects: Halos (Meteorology), Meteorological optics, Rainbow, Rainbows.
eBay marketplace picks
Marketplace Samples
Live-tested eBay searches with available results related to this page.
Selected fromUFO poster oneBay.co.uk.
Current eBay listing
I Want To Believe UFO Poster Giclée Fine Art Heavyweight Print
Current eBay listing
VINTAGE UFO FLYING SAUCERS COMIC ADVERTISING A2 POSTER PRINT
Endnotes
1.
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...
2.
Source: itv.com
Link:https://www.itv.com/news/westcountry/2021-03-04/man-left-shocked-as-large-ship-appears-to-float-in-the-sky
Source snippet
XMan left shocked as large ship appears to float in the sky | ITV News West CountryMarch 4, 2021...
Published: March 4, 2021
3.
Source: files.ncas.org
Title: Files Condon Report, Sec III, Chapter 5: Optical & Radar Analysis
Link:https://files.ncas.org/condon/text/s3chap05.htm
4.
Source: the-independent.com
Link:https://www.the-independent.com/news/uk/home-news/flying-ship-cornwall-optical-illusion-b2086169.html
5.
Source: the-independent.com
Title: ‘Floating’ ship spotted off Cornwall coast | The Independent
Link:https://www.the-independent.com/news/uk/home-news/floating-ship-cornwall-optical-illusion-mirage-b1813457.html
6.
Source: forum.index.hu
Title: hu Az UFO-król
Link:https://forum.index.hu/Article/showArticle?na_order=&na_start=3048&na_step=500&t=9003012&token=62935de4e8f7f3f3ff2c52dfbdef89f1
7.
Source: files.ncas.org
Link:https://files.ncas.org/condon/text/case35.htm
8.
Source: files.ncas.org
Link:https://files.ncas.org/condon/text/s6chap05.htm
9.
Source: files.ncas.org
Link:https://files.ncas.org/condon/text/case01.htm
10.
Source: files.ncas.org
Link:https://files.ncas.org/condon/text/contents.htm
11.
Source: files.ncas.org
Link:https://files.ncas.org/condon/text/case17.htm
12.
Source: files.ncas.org
Link:https://files.ncas.org/condon/text/s3chap04.htm
13.
Source: files.ncas.org
Link:https://files.ncas.org/condon/text/sec-i.htm
14.
Source: files.ncas.org
Title: sec ii
Link:https://files.ncas.org/condon/text/sec-ii.htm
15.
Source: condon.ncas.org
Link:https://condon.ncas.org/text/intro.htm
16.
Source: files.ncas.org
Title: appndx q
Link:https://files.ncas.org/condon/text/appndx-q.htm
17.
Source: theguardian.com
Link:https://www.theguardian.com/science/2021/mar/05/ship-hovering-above-sea-cornwall-optical-illusion
Source snippet
The GuardianWalker 'stunned' to see ship hovering high above sea off Cornwall | Science | The GuardianMarch 5, 2021...
Published: March 5, 2021
18.
Source: independent.co.uk
Title: The Independent‘Floating’ ship spotted off Cornwall coast | The Independent
Link:https://www.independent.co.uk/news/uk/home-news/floating-ship-cornwall-optical-illusion-mirage-b1813457.html
19.
Source: cloudatlas.wmo.int
Title: International Cloud Atlas Mirage | International Cloud Atlas
Link:https://cloudatlas.wmo.int/mirage.html
20.
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...
21.
Source: theguardian.com
Link:https://www.theguardian.com/science/2021/mar/18/pop-up-enabled-ship-hover-dorset-coast-superior-mirage
Source snippet
The GuardianSecond vessel in two weeks appears to float above UK waters | Science | The GuardianMarch 18, 2021...
Published: March 18, 2021
22.
Source: atoptics.org.uk
Title: Atmospheric Optics OPOD
Link:https://www.atoptics.org.uk/fz782.htm
Source snippet
Atmospheric OpticsOPOD - 4 ship superior mirageMarch 25, 2012...
Published: March 25, 2012
23.
Source: atoptics.org.uk
Title: Atmospheric Optics Strange Ships, Superior Mirages
Link:https://www.atoptics.org.uk/fz150.htm
24.
Source: physics.stackexchange.com
Title: Physics Stack Exchangeoptics
Link:https://physics.stackexchange.com/q/619022/123208
25.
Source: physics.stackexchange.com
Title: Physics Stack Exchangeoptics
Link:https://physics.stackexchange.com/questions/619022/how-does-the-cornwall-floating-ship-illusion-work?noredirect=1
26.
Source: weather.metoffice.gov.uk
Title: metoffice.gov.uk Shipping forecast and gale warnings
Link:https://weather.metoffice.gov.uk/specialist-forecasts/coast-and-sea/shipping-forecast
27.
Source: metoffice.gov.uk
Title: Marine heatwaves: why warm seas matter for UK weather
Link:https://www.metoffice.gov.uk/blog/2026/marine-heatwaves-why-warm-seas-matter-for-uk-weather
28.
Source: metoffice.gov.uk
Title: Long-lasting UK marine heatwave likely to reach extreme levels next week
Link:https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2026/long-lasting-uk-marine-heatwave-likely-to-reach-extreme-levels-next-week
29.
Source: metoffice.gov.uk
Title: Deep Dive: High-pressure, dry air and meteor showers
Link:https://www.metoffice.gov.uk/blog/2026/met-office-deep-dive-for-april-22
30.
Source: metoffice.gov.uk
Title: Met Office Deep Dive: A change on the way, but when?
Link:https://www.metoffice.gov.uk/blog/2025/met-office-deep-dive-a-change-on-the-way-but-when
31.
Source: metoffice.gov.uk
Title: Mist, fog, and haze: What’s the difference?
Link:https://www.metoffice.gov.uk/blog/2025/whats-the-difference-between-mist-fog-and-haze
32.
Source: metoffice.gov.uk
Title: Met Office Deep Dive: Hot weather to bring heatwave for many
Link:https://www.metoffice.gov.uk/blog/2025/met-office-deep-dive-hot-weather-to-bring-heatwaves-for-much-of-the-country
33.
Source: weather.gov.hk
Title: Mirage｜Hong Kong Observatory(HKO)｜Observatory’s Blog
Link:https://www.weather.gov.hk/en/Observatorys-Blog/104520/Mirage
34.
Source: library.metoffice.gov.uk
Title: Record View
Link:https://library.metoffice.gov.uk/portal/Default/en-GB/RecordView/Index/471177
35.
Source: library.metoffice.gov.uk
Title: Record View
Link:https://library.metoffice.gov.uk/portal/Default/en-GB/RecordView/Index/489292
36.
Source: metoffice.gov.uk
Title: Aerodrome Weather Warnings
Link:https://www.metoffice.gov.uk/services/transport/aviation/regulated/training-resources-for-aviation/aerodrome-warnings
37.
Source: weather.metoffice.gov.uk
Title: metoffice.gov.uk Marine observations
Link:https://weather.metoffice.gov.uk/specialist-forecasts/coast-and-sea/observations/3827
38.
Source: cloudatlas.wmo.int
Link:https://cloudatlas.wmo.int/en/mirage.html
39.
Source: skybrary.aero
Link:https://skybrary.aero/index.php/articles/fata-morgana
40.
Source: physics.stackexchange.com
Title: how does the cornwall floating ship illusion work
Link:https://physics.stackexchange.com/questions/619022/how-does-the-cornwall-floating-ship-illusion-work
41.
Source: spark.iop.org
Link:https://spark.iop.org/mirages
42.
Source: facebook.com
Title: Fata Morgana
Link:https://www.facebook.com/lokieadventures/videos/fata-morgana-illusion-at-sea-super-super-cool-first-time-ive-seen-it-to-this-ext/1705123970662927/
43.
Source: aty.sdsu.edu
Link:https://aty.sdsu.edu/mirages/bochoven/text.html
44.
Source: aty.sdsu.edu
Link:https://aty.sdsu.edu/papers/Zenit/glance.html
45.
Source: hyperphysics.phy-astr.gsu.edu
Link:https://www.hyperphysics.phy-astr.gsu.edu/hbase/atmos/mirage.html
Additional References
46.
Source: cbsnews.com
Link:https://www.cbsnews.com/news/floating-ship-optical-illusion-superior-mirage-cornwall-england/
Source snippet
CBS NewsPhotos appear to show a giant ship hovering over the water off the English coast - CBS News...
47.
Source: youtube.com
Title: What is Fata Morgana or mirage? What causes it? What is The Flying Dutchman?
Link:https://www.youtube.com/watch?v=Gk2ewkVt3TY
Source snippet
This video explains how temperature inversions and atmospheric refraction create superior mirages, making distant ships appear to float i...
48.
Source: youtube.com
Title: A floating freighter? The science of refraction, mirages
Link:https://www.youtube.com/watch?v=d5Qbnemmzbw
Source snippet
What is Fata Morgana or mirage? What causes it? What is The Flying Dutchman?...
49.
Source: youtube.com
Title: What is Superior Mirage? Why the Ship looks Floating?
Link:https://www.youtube.com/watch?v=Uy9adgmxQ_A
Source snippet
Optical illusion creates 'UFO mirage' over sea in Alaska...
50.
Source: youtube.com
Title: Optical illusion creates ‘UFO mirage’ over sea in Alaska
Link:https://www.youtube.com/watch?v=iennvrKaAzQ
Source snippet
Fata Morgana Floating Ship Optical Illusion...
51.
Source: globalnews.ca
Link:https://globalnews.ca/news/7679642/floating-ship-optical-illusion-superior-mirage/
52.
Source: facebook.com
Link:https://www.facebook.com/guangdongtoday/posts/guangdong-a-ship-was-seen-floating-in-the-sky-in-shenzhen-some-netizens-speculat/4281250351983186/
53.
Source: facebook.com
Link:https://www.facebook.com/groups/themelvillesociety/posts/10159496543844114/
54.
Source: facebook.com
Link:https://www.facebook.com/cornwalllivenews/posts/a-baffling-sight-off-st-ives-as-a-ship-appears-to-float-above-the-horizonthe-dra/1423568099796506/
55.
Source: facebook.com
Link:https://www.facebook.com/Q2News/posts/a-man-says-he-was-stunned-to-look-out-to-sea-from-a-village-in-cornwall-in-south/10151349031024982/