Within Atmosphere
Why a star can look alive
Low stars and planets can flash colours, wobble and seem active when their light crosses turbulent air near the horizon.
On this page
- Why low stars twinkle more strongly
- Colour flashes, wobble and false motion
- Camera zoom traps in star and planet videos
Page outline Jump by section
Introduction
A surprisingly large number of UFO reports begin with an ordinary star or planet low in the sky. Near the horizon, starlight must pass through a much thicker layer of Earth’s atmosphere than it does overhead. Turbulent air, temperature differences and atmospheric refraction can make a steady point of light appear to flash, change colour, wobble, dart about or even seem intelligent in its movements. Astronomers call this effect scintillation, but to an observer who is not expecting it, the light can look remarkably active. NASA and other astronomy organisations have long noted that atmospheric turbulence causes stars to twinkle and shift in apparent brightness and position, while bright objects near the horizon are especially vulnerable to dramatic visual distortion. [StarChild]starchild.gsfc.nasa.govStar Child Why do stars twinkle?StarChildWhy do stars twinkle? - StarChild - NASAThe movement of air (sometimes called turbulence) in the atmosphere of Earth causes the… [Space Place]spaceplacecanada.caSpace PlaceWhy do stars twinkle?25 Jan 2020 — Light from objects straight overhead (at zenith) travel through less air compared to stars…
Within the broader category of clouds, mirages and atmospheric distortion, twinkling stars are important because they create UFO reports without requiring any unusual object in the sky. The atmosphere itself supplies much of the apparent motion.
Why a star can look alive
Stars are so distant that they appear as tiny points of light. As that light passes through layers of moving air with different temperatures and densities, it is continually bent by small amounts. The result is rapid fluctuations in brightness and apparent position. To the eye, the star seems to flicker, pulse or dance. [StarChild]starchild.gsfc.nasa.govStar Child Why do stars twinkle?StarChildWhy do stars twinkle? - StarChild - NASAThe movement of air (sometimes called turbulence) in the atmosphere of Earth causes the… ResearchGate The effect is strongest when a star is low above the horizon. Light arriving from a low angle travels through far more atmosphere than light [researchgate.net]researchgate.netResearchGate(PDF) Using stellar scintillation for studies of turbulence in…9 Mar 2016 — Stellar scintillation observed through the Ear… from a star overhead, increasing the opportunities for turbulence to distort it. Astronomical sources consistently note that scintillation becomes much more pronounced near the horizon. [Space Place]spaceplacecanada.caSpace PlaceWhy do stars twinkle?25 Jan 2020 — Light from objects straight overhead (at zenith) travel through less air compared to stars… [wikipedia]WikipediaTwinklingIn simple terms, twinkling of stars is caused by the passing of light through different layers of a turbulent atmosphere. Mos… For UFO investigations, this matters because many reports describe a bright light that appears stationary at first but then seems to shimmer, pulse or drift unpredictably. If the object remains fixed relative to the stars yet displays these atmospheric effects, a bright star or planet becomes a plausible explanation.
Why low stars twinkle more strongly
The atmosphere acts less like a smooth lens and more like a constantly shifting stack of weak lenses. When looking near the horizon, observers are effectively viewing through a much longer optical path. Every turbulent layer adds a small distortion.
Several consequences follow:
- Brightness can change several times per second.
- The apparent position of the star can shift slightly and repeatedly.
- Different colours can be bent by different amounts.
- The distortions become more noticeable in humid, unstable or turbulent conditions. [StarChild]starchild.gsfc.nasa.govStar Child Why do stars twinkle?StarChildWhy do stars twinkle? - StarChild - NASAThe movement of air (sometimes called turbulence) in the atmosphere of Earth causes the… ResearchGate This is why famous bright stars such as Sirius [researchgate.net]researchgate.netResearchGate(PDF) Using stellar scintillation for studies of turbulence in…9 Mar 2016 — Stellar scintillation observed through the Ear…, Antares and other luminous horizon stars often attract attention. Observers frequently report them as unusual objects because their flashing and colour changes are much more dramatic than those of fainter stars higher in the sky. Astronomy discussions and observing guides routinely identify these stars as sources of mistaken UFO reports when atmospheric conditions are poor. [Chandra X-ray Observatory]chandra.harvard.eduSource details in endnotes. [Cloudy Nights]cloudynights.com547826 antares particular blinking apearanceAntares' particular blinking apearance24 Aug 2016 — Both stars are often the source of "UFO" reports. There are two phenomena in effect w…
Planets can also be involved. Although planets usually twinkle less because they present a tiny disc rather than a perfect point source, a bright planet low on the horizon can still flash and shimmer enough to trigger reports. Venus, in particular, has a long history of being mistaken for a UFO. [noaa]repository.library.noaa.govnoaa 32474 DS1NOAA Institutional Repository^ 0Fc0 ^rEs o* W6by JH Churnside · 1989 · Cited by 27 — If the signal is averaged over a finite disk, such a… Institutional Repository [The Christian Science Monitor]csmonitor.comBright Venus may prompt UFO sightingsThe Christian Science MonitorBright Venus may prompt UFO sightings2 Nov 2010 — An extended daylight savings time will mean that Venus wil…
Colour flashes, wobble and false motion
One reason these sightings can seem so convincing is that the atmosphere does more than alter brightness. It can create rapid colour changes and the illusion of movement.
Why stars flash red, green and blue
Air bends different colours of light by slightly different amounts. Near the horizon, this atmospheric dispersion can separate colours enough that turbulence continually shifts which colour reaches the observer most strongly. A bright star may therefore appear to flash red, green, blue and white in rapid succession. Astronomers commonly cite Sirius as a striking example. [Chandra X-ray Observatory]chandra.harvard.eduSource details in endnotes. [Cloudy Nights]cloudynights.com764513 about the twinkling of starsAbout the twinkling of stars3 Apr 2021 — Refractive dispersion is due to the fact that air bends blue light more than red, so that a star…
To someone unfamiliar with the phenomenon, these colour changes can resemble artificial lighting patterns rather than a natural astronomical object.
Why a stationary light seems to move
Human vision is not especially good at judging the position of a lone light against a dark sky. When a star scintillates strongly, tiny apparent shifts combine with normal eye movements and the brain’s tendency to seek patterns. The result can be a sincere impression that the light is hovering, drifting, zig-zagging or responding to observation. Reddit [StarChild Witnesses often describe:]starchild.gsfc.nasa.govStar Child Why do stars twinkle?StarChildWhy do stars twinkle? - StarChild - NASAThe movement of air (sometimes called turbulence) in the atmosphere of Earth causes the…
- Sudden side-to-side movement.
- Small loops or arcs.
- Hovering followed by brief jumps.
- Motion that disappears when viewed against fixed landmarks.
These perceptions can be genuine experiences without reflecting actual movement of the object itself.
Camera zoom traps in star and planet videos
Modern smartphones and consumer cameras often make the effect look even more dramatic. When a bright star is recorded at high digital zoom, the camera magnifies not only the object but also every atmospheric distortion and every tiny movement of the device.
A star that appears as a stable point to the naked eye can become a flashing blob on screen. Autofocus systems may continually hunt for focus, causing the object to swell, shrink or change shape. Image stabilisation and compression artefacts can create additional apparent motion. Atmospheric turbulence then causes the enlarged image to ripple and dance. [ResearchGate]researchgate.netResearchGate(PDF) Using stellar scintillation for studies of turbulence in…9 Mar 2016 — Stellar scintillation observed through the Ear…
This explains a common pattern in UFO videos:
Amazon book picks
Further Reading
Books and field guides related to Why a star can look alive. Use these as the next step if you want deeper reading beyond the article.
Light and Color in the Outdoors
Discusses scintillation and atmospheric visual effects.
The Backyard Astronomer's Guide
Builds understanding of observing conditions and celestial objects.
eBay marketplace picks
Marketplace Samples
Example marketplace items related to this page. Use the search link to explore similar finds on eBay.
- A bright light is recorded near the horizon. [reddit.com]reddit.comdisappearing light near venusr/AstronomyThe ISS moves very fast high in the sky and it moves slowly on the horizon…. July 9 2022 Boulder, CO - UFO Sighting? A Mete…
- Heavy zoom turns it into a large glowing object.
- Atmospheric turbulence makes the image flicker and distort.
- The resulting footage appears to show a structured craft changing shape or manoeuvring.
Astronomy communities regularly identify such recordings as heavily magnified stars or planets undergoing normal atmospheric scintillation. [Reddit]reddit.comRedditSomething weird was happening with the star in the middle…This phenomenon, known as atmospheric scintillation, causes stars to a…
Clues that the “UFO” is actually a twinkling star
Several observational clues point towards an atmospheric explanation rather than an unknown craft:
- The light remains in roughly the same area of sky for long periods.
- It is low above the horizon.
- Colour changes are rapid and irregular.
- The apparent motion becomes less dramatic when viewed through binoculars or compared with nearby stars.
- Astronomical software shows a bright star or planet in the same position.
- Multiple observers record different impressions of shape or movement. [Night Sky Network]nightsky.jpl.nasa.govNight Sky Network Identifying UFOs and UAPsBe polite and patient. If the "UFO" is visible and the person inquiring is there in person, you can…Read more… [The Christian Science Monitor]csmonitor.comBright Venus may prompt UFO sightingsThe Christian Science MonitorBright Venus may prompt UFO sightings2 Nov 2010 — An extended daylight savings time will mean that Venus wil…
In many UFO cases, the most puzzling feature is not the object itself but the atmosphere between the observer and the object. A bright star shining through turbulent air can appear unexpectedly dynamic, producing flashes, colour shifts and apparent manoeuvres that seem extraordinary until the optical effects are understood. [StarChild]starchild.gsfc.nasa.govStar Child Why do stars twinkle?StarChildWhy do stars twinkle? - StarChild - NASAThe movement of air (sometimes called turbulence) in the atmosphere of Earth causes the… [Wikipedia]WikipediaTwinklingIn simple terms, twinkling of stars is caused by the passing of light through different layers of a turbulent atmosphere. Mos…
Endnotes
-
Source: starchild.gsfc.nasa.gov
Title: Star Child Why do stars twinkle?
Link: https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question26.htmlSource snippet
StarChildWhy do stars twinkle? - StarChild - NASAThe movement of air (sometimes called turbulence) in the atmosphere of Earth causes the...
-
Source: Wikipedia
Link: https://en.wikipedia.org/wiki/TwinklingSource snippet
TwinklingIn simple terms, twinkling of stars is caused by the passing of light through different layers of a turbulent atmosphere. Mos...
-
Source: researchgate.net
Link: https://www.researchgate.net/publication/233775239_Using_stellar_scintillation_for_studies_of_turbulence_in_the_Earth%27s_atmosphereSource snippet
ResearchGate(PDF) Using stellar scintillation for studies of turbulence in...9 Mar 2016 — Stellar scintillation observed through the Ear...
-
Source: reddit.com
Link: https://www.reddit.com/r/Astronomy/comments/1ecfzh6/something_weird_was_happening_with_the_star_in/Source snippet
RedditSomething weird was happening with the star in the middle...This phenomenon, known as atmospheric scintillation, causes stars to a...
-
Source: repository.library.noaa.gov
Title: noaa 32474 DS1
Link: https://repository.library.noaa.gov/view/noaa/32474/noaa_32474_DS1.pdfSource snippet
NOAA Institutional Repository^ 0Fc0 ^rEs o* W6by JH Churnside · 1989 · Cited by 27 — If the signal is averaged over a finite disk, such a...
-
Source: nightsky.jpl.nasa.gov
Title: Night Sky Network Identifying UFOs and UAPs
Link: https://nightsky.jpl.nasa.gov/news/39/Source snippet
Be polite and patient. If the "UFO" is visible and the person inquiring is there in person, you can...Read more...
-
Source: reddit.com
Title: disappearing light near venus
Link: https://www.reddit.com/r/Astronomy/comments/x9vgii/disappearing_light_near_venus/Source snippet
r/AstronomyThe ISS moves very fast high in the sky and it moves slowly on the horizon.... July 9 2022 Boulder, CO - UFO Sighting? A Mete...
-
Source: reddit.com
Link: https://www.reddit.com/r/aliens/comments/1syqcee/what_is_this/Source snippet
What is this??: r/aliensPentagon UFO Files Release: Pastors Warn Secret Files Detail 'Demonic Entities' · r/aliens - Pentagon UFO Files...
-
Source: reddit.com
Link: https://www.reddit.com/r/askastronomy/comments/jh4qyq/why_dont_some_stars_twinkle/Source snippet
Why don't some stars twinkle?: r/askastronomyI'm not mistaking those stars for planets, I just thought of this randomly, if stars twinkl...
-
Source: reddit.com
Link: https://www.reddit.com/r/AskPhysics/comments/ripgx5/why_do_some_astronomers_say_that_stars_twinkle/Source snippet
rough our atmosphere, causing small variations in its...Read more...
-
Source: reddit.com
Link: https://www.reddit.com/r/explainlikeimfive/comments/1oqi03i/eli5_why_do_stars_twinkle_when_we_look_at_them/Source snippet
less of where it comes from.Read more...
-
Source: ntrs.nasa.gov
Link: https://ntrs.nasa.gov/api/citations/19890017910/downloads/19890017910.pdfSource snippet
Technical Reports Serverby JH Churnside · 1989 · Cited by 27 — Therefore, for direct detection, the only significant effect of atmospheri...
-
Source: space.com
Title: why do stars twinkle
Link: https://www.space.com/why-do-stars-twinkleSource snippet
?Jul 4, 2022 — "Starlight gets refracted [bent] by the atmosphere a little bit, which can cause it to change color," French said. This ef...
-
Source: spaceplacecanada.ca
Link: https://www.spaceplacecanada.ca/2020/01/25/twinklingstars/Source snippet
Space PlaceWhy do stars twinkle?25 Jan 2020 — Light from objects straight overhead (at zenith) travel through less air compared to stars...
-
Source: chandra.harvard.edu
Link: https://chandra.harvard.edu/resources/faq/astrophysics/astrophysics-27.html -
Source: cloudynights.com
Title: 547826 antares particular blinking apearance
Link: https://www.cloudynights.com/forums/topic/547826-antares-particular-blinking-apearance/Source snippet
Antares' particular blinking apearance24 Aug 2016 — Both stars are often the source of "UFO" reports. There are two phenomena in effect w...
-
Source: csmonitor.com
Title: [Bright Venus]({{ ‘bright-venus/’ | relative_url }}) may prompt UFO sightings
Link: https://www.csmonitor.com/Science/2010/1102/Bright-Venus-may-prompt-UFO-sightingsSource snippet
The Christian Science MonitorBright Venus may prompt UFO sightings2 Nov 2010 — An extended daylight savings time will mean that Venus wil...
-
Source: cloudynights.com
Title: 764513 about the twinkling of stars
Link: https://www.cloudynights.com/forums/topic/764513-about-the-twinkling-of-stars/Source snippet
About the twinkling of stars3 Apr 2021 — Refractive dispersion is due to the fact that air bends blue light more than red, so that a star...
Additional References
-
Source: nationalacademies.org
Link: https://www.nationalacademies.org/read/25802/chapter/9Source snippet
Chapter: 7 The Cosmic Plasma FrontierThis ubiquitous mechanism is thought to explain the onset of stellar and accretion-disk flares and m...
-
Source: events.spacepole.be
Link: https://events.spacepole.be/event/259/attachments/1762/3618/SWIC%20SWx%20acronyms.pdfSource snippet
(1) Area; (2) Article; (3). Ampère; (4): Mount Wilson classification: a magnetically unipolar sunspot group. (alpha) aa, AA. A 3-hour...
-
Source: universemagazine.com
Title: known flying objects sky phenomena we often mistake for ufos
Link: https://universemagazine.com/en/known-flying-objects-sky-phenomena-we-often-mistake-for-ufos/?srsltid=AfmBOoqx52o0acitQPLsoRGKbs3K56V8VgeqfMqPP6rMO6I2yKWX9cz7Source snippet
Known Flying Objects: Sky Phenomena We Often Mistake...12 Oct 2024 — In this article, we delve into the subject of UFOs, particularly th...
-
Source: aol.com
Link: https://www.aol.com/articles/ufo-improbability-summer-solstice-venus-090211346.htmlSource snippet
UFO improbability, summer solstice and Venus hugging a...4 days ago — UFO improbability, summer solstice and Venus hugging a crescent moon...
-
Source: beachconnection.net
Title: Here you’re dealing with refraction – or the bending of light.Read more
Link: https://www.beachconnection.net/news/why_stars_twinkle_colors102320.phpSource snippet
Why Stars Twinkle, Change Colors: Portland, Oregon...Oct 23, 2020 — The farther down the horizon, the more layers of atmosphere you're d...
-
Source: medium.com
Link: https://medium.com/%40omarvferro/when-the-sky-tricked-us-the-most-famous-ufos-that-turned-out-to-be-nothing-but-nature-showing-5359c8ff815aSource snippet
misidentified as flashing or moving UFOs near the horizon.Read more...
-
Source: kqed.org
Title: ufo lgm omg what is that thing in the sky
Link: https://www.kqed.org/quest/35359/ufo-lgm-omg-what-is-that-thing-in-the-skySource snippet
UFO? LGM? OMG! What is That Thing in the Sky?20 Apr 2012 — UFO? LGM? OMG! What is That Thing in the Sky? Ever seen something in the sky t...
-
Source: facebook.com
Title: You can see it changing colours in real
Link: https://www.facebook.com/groups/AstronomyNo1/posts/5192188810826159/Source snippet
Can anyone explain what this is please it seemed to be...Can anyone explain what this is please it seemed to be some sort of star but it...
-
Source: facebook.com
Link: https://www.facebook.com/livermore.lab/posts/why-do-stars-twinkle-the-blustery-mixing-of-earths-atmosphere-restricts-our-abil/1231156372373327/Source snippet
lity to see the universe clearly from the ground...
-
Source: forbes.com
Title: UFO Sightings Will Soon Peak
Link: https://www.forbes.com/sites/jamiecartereurope/2019/09/13/ufo-sightings-will-soon-peak-dont-blame-the-government/Source snippet
Don't Blame The Government13 Sept 2019 — That's sure to be a pretty sight. Venus and UFO sightings. The planet Venus often gets mistaken...
Topic Tree