Within Stars
Why Sirius So Often Looks Like a UFO
Sirius can look like a pulsing red, green and white object when it sits low in turbulent air.
On this page
- Why Sirius draws attention near the horizon
- How colour flashes mimic navigation lights
- How to check Sirius against a sighting time
Page outline Jump by section
Introduction
Among all the astronomical objects that generate UFO reports, Sirius has an unusually strong track record. The reason is not that Sirius behaves strangely, but that it is the brightest star visible in the night sky and often appears low above the horizon for observers in the Northern Hemisphere. Under those conditions it can flash rapidly between red, green, blue and white, pulse in brightness and seem to shimmer or move. To an observer expecting a distant aircraft, drone or unidentified craft, the display can look remarkably artificial. Astronomers have long noted that Sirius’s brightness, colour changes and twinkling frequently lead people to mistake it for a UFO. [EarthSky]earthsky.orgEarthSky | Updates on your cosmos and worldSun news for May 15, 2026. A G2 geomagetic storm is expected today as solar winds ramp up. Aur…
Why Sirius Draws Attention Near the Horizon
Sirius stands out because it is exceptionally bright. Its apparent brightness makes atmospheric effects much easier to notice than they are on fainter stars. When Sirius is viewed low in the sky, its light must pass through a much thicker layer of Earth’s atmosphere than it would if it were overhead. Turbulent air, temperature gradients, dust and moisture distort the incoming light, producing dramatic scintillation—the scientific term for twinkling. [EarthSky]earthsky.orgEarthSky | Updates on your cosmos and worldSun news for May 15, 2026. A G2 geomagetic storm is expected today as solar winds ramp up. Aur… [Sky & Telescope]skyandtelescope.orgsirius ly scintillating holiday12222014Sky & TelescopeHave a Sirius-ly Scintillating Holiday!Dec 22, 2014 — Sirius twinkles more than most stars because it's bright, making twi…
This combination of brightness and low altitude is what makes Sirius such a common UFO trigger. Other stars twinkle too, but Sirius is bright enough for the colour changes to become obvious to the naked eye. Observers often report a stationary object that appears brighter than surrounding stars and flashes in a way that seems deliberate rather than natural. [EarthSky]earthsky.orgEarthSky | Updates on your cosmos and worldSun news for May 15, 2026. A G2 geomagetic storm is expected today as solar winds ramp up. Aur… [Earth Sky]earthsky.orgEarthSky | Updates on your cosmos and worldSun news for May 15, 2026. A G2 geomagetic storm is expected today as solar winds ramp up. Aur… The effect is especially noticeable from locations in northern Europe and similar latitudes, where Sirius never climbs particularly high above the southern horizon. Amateur astronomers in the United Kingdom frequently remark that Sirius displays unusually strong colour flashes because it remains relatively low in the sky. [Stargazers Lounge]stargazerslounge.comStargazers Lounge Why does Sirius sparkle with different colours?Observing23 Jan 2010 — Sirius twinkles because it is so low down to the horizon as seen from the UK. The light from it has to travel thro…
How Colour Flashes Mimic Navigation Lights
The most convincing aspect of the illusion is the colour pattern. White starlight contains all visible colours. Near the horizon, atmospheric refraction can separate those colours slightly, while constantly changing air currents redirect them toward the observer. The result is a rapid sequence of red, green, blue and white flashes. [EarthSky]earthsky.orgEarthSky | Updates on your cosmos and worldSun news for May 15, 2026. A G2 geomagetic storm is expected today as solar winds ramp up. Aur… [Universe Today]universetoday.comsirius ufo trickster extraordinaireUniverse TodaySirius, UFO trickster extraordinaire23 Mar 2014 — When Sirius is low above the horizon, refraction (bending of light) is st…
To a witness unfamiliar with atmospheric optics, these flashes can resemble the navigation lights of an aircraft. Unlike a distant plane, however, Sirius remains fixed relative to the background stars. Yet human perception often interprets the changing colours and brightness as evidence of motion or manoeuvring. Witnesses may describe the object as:
- Hovering motionless while emitting coloured lights.
- Pulsing or signalling in a repeating pattern.
- Rotating because different colours appear around the light.
- Changing shape as the flashes vary in intensity.
- Moving slightly due to visual illusions created by eye movements and atmospheric distortion.
These descriptions closely match many UFO reports involving a single bright light low in the sky. Astronomical publications have repeatedly highlighted Sirius as a classic example of a natural object mistaken for an unidentified craft because of these effects. [Universe Today]universetoday.comsirius ufo trickster extraordinaireUniverse TodaySirius, UFO trickster extraordinaire23 Mar 2014 — When Sirius is low above the horizon, refraction (bending of light) is st…
Real UFO Reports and the Sirius Pattern
A recurring pattern appears in UFO communities and observational forums. Witnesses often report a bright, stationary object displaying vivid colours and unusual flashing behaviour. After checking the location against star charts or astronomy apps, the object frequently turns out to be Sirius. [Reddit]reddit.comWhat is this??: r/UFOsRedditWhat is this??: r/UFOsApril 20, 2025 — It's a star. Most likely Sirius. The flashing colors are called scintillation due to the e… [Reddit]reddit.comSee a stationary orb emitting different colors?It's the star…Scintillation (the changing colors and 'shimmering' appearance) is noticeable both in and out of focus with very bright…
The reports tend to share several characteristics:
- The object is observed for a long period without significant movement across the local landscape.
- It appears brightest shortly after rising or before setting.
- Colour changes are a major part of the sighting description.
- Multiple observers can see the effect simultaneously.
- The object’s position matches Sirius when checked astronomically.
This does not mean every report involving flashing lights is Sirius. However, when a sighting centres on a bright stationary object displaying rapidly changing colours near the horizon, Sirius becomes one of the first conventional explanations investigators consider. [EarthSky]earthsky.orgEarthSky | Updates on your cosmos and worldSun news for May 15, 2026. A G2 geomagetic storm is expected today as solar winds ramp up. Aur… [Universe Today]universetoday.comsirius ufo trickster extraordinaireUniverse TodaySirius, UFO trickster extraordinaire23 Mar 2014 — When Sirius is low above the horizon, refraction (bending of light) is st…
How to Check Sirius Against a Sighting Time
Because Sirius follows a predictable path, it is usually straightforward to test whether it could explain a reported sighting.
First, determine the exact time and location of the observation. Then compare that information with a planetarium application or star chart. If Sirius occupied the same part of the sky at that moment, the identification becomes plausible. [Reddit]reddit.comOpen source on reddit.com.
Several clues strengthen the Sirius explanation:
- The object remained essentially fixed. Over minutes it may appear stationary, though over an hour it will drift slowly with the stars.
- The strongest colour flashes occurred near the horizon. Scintillation weakens as Sirius climbs higher.
- Binoculars or a telescope revealed a star-like point rather than a structured craft.
- The colours appeared random rather than forming a consistent lighting pattern.
- The object’s position matched Sirius on an astronomical chart.
A useful practical test is simply to observe the object later in the night. If it becomes steadier and less colourful as it rises, atmospheric scintillation is the likely cause. [Sky & Telescope]skyandtelescope.orgsirius ly scintillating holiday12222014Sky & TelescopeHave a Sirius-ly Scintillating Holiday!Dec 22, 2014 — Sirius twinkles more than most stars because it's bright, making twi… [Sky at]skyatnightmagazine.comwhy do stars twinkle?2 May 2025 — Stars appear to twinkle because their light passes through our atmosphere and is bent and distorted by varying temperatures…
Why Sirius Remains a Persistent UFO Trigger
Sirius occupies a perfect intersection of factors that encourage misidentification. It is bright enough to dominate the sky, low enough to experience strong atmospheric distortion, and visually dramatic enough to seem unlike an ordinary star. The resulting flashes of red, green and white can resemble technological lighting far more closely than most people expect from a celestial object. For that reason, Sirius continues to be one of the most frequently identified astronomical sources behind reports of hovering, colour-changing UFOs. [EarthSky]earthsky.orgEarthSky | Updates on your cosmos and worldSun news for May 15, 2026. A G2 geomagetic storm is expected today as solar winds ramp up. Aur… [Universe Today]universetoday.comsirius ufo trickster extraordinaireUniverse TodaySirius, UFO trickster extraordinaire23 Mar 2014 — When Sirius is low above the horizon, refraction (bending of light) is st…
eBay marketplace picks
Marketplace Samples
Example marketplace items related to this page. Use the search link to explore similar finds on eBay.
Endnotes
-
Source: earthsky.org
Link: https://earthsky.org/brightest-stars/sirius-the-brightest-star/Source snippet
EarthSkySee Sirius, the brightest star in the night skyFeb 10, 2026 — The brightness, twinkling and color changes sometimes prompt people...
-
Source: earthsky.org
Title: is sirius the most luminous star in the sky
Link: https://earthsky.org/astronomy-essentials/is-sirius-the-most-luminous-star-in-the-sky/Source snippet
EarthSkyIs Sirius the most luminous star in the sky?4 Mar 2026 — The colors of Sirius. Many people comment that they see Sirius flashing...
-
Source: earthsky.org
Title: the skys brightest star sirius before dawn
Link: https://earthsky.org/tonight/the-skys-brightest-star-sirius-before-dawn/Source snippet
EarthSkySee brightest star, Sirius, in your morning sky29 Oct 2025 — Sirius appears to flash different colors when it's low in the sky...
-
Source: earthsky.org
Link: https://earthsky.org/todays-image/photo-sirius-in-many-colors/Source snippet
EarthSkySirius in many colors | Astronomy Essentials15 Dec 2017 — When you see this very bright star low in the sky, it appears to flash...
-
Source: reddit.com
Title: What is this??: r/UFOs
Link: https://www.reddit.com/r/UFOs/comments/1k3wguz/what_is_this/Source snippet
RedditWhat is this??: r/UFOsApril 20, 2025 — It's a star. Most likely Sirius. The flashing colors are called scintillation due to the e...
Published: April 20, 2025
-
Source: reddit.com
Title: See a stationary orb emitting different colors?
Link: https://www.reddit.com/r/UFOs/comments/15yolb6/see_a_stationary_orb_emitting_different_colors/Source snippet
It's the star...Scintillation (the changing colors and 'shimmering' appearance) is noticeable both in and out of focus with very bright...
-
Source: reddit.com
Link: https://www.reddit.com/r/Astronomy/comments/1aw3slg/does_sirius_always_flicker_this_much/ -
Source: earthsky.org
Title: flashing star autumn capella arcturus sirius
Link: https://earthsky.org/astronomy-essentials/flashing-star-autumn-capella-arcturus-sirius/Source snippet
Flashing star in autumn? Here are 3 candidates3 Oct 2024 — Sirius appears to flash different colors when it's low in the sky. Really, all...
-
Source: earthsky.org
Link: https://earthsky.org/Source snippet
EarthSky | Updates on your cosmos and worldSun news for May 15, 2026. A G2 geomagetic storm is expected today as solar winds ramp up. Aur...
Published: May 15, 2026
-
Source: earthsky.org
Title: What star in the northeast flashes colorfully?
Link: https://earthsky.org/tonight/what-star-in-the-northeast-flashes-red-and-green/Source snippet
It's Capella!Oct 10, 2025 — The bright star Capella in the constellation Auriga the Charioteer is the star in the northeast that flashes...
-
Source: astronomy.com
Title: simply scintillating
Link: https://www.astronomy.com/science/simply-scintillating/Source snippet
18 May 2023 — Twinkling, the common term for stellar “scintillation,” refers to tiny, rapid changes in a star's apparent pos...
Published: May 2023
-
Source: universetoday.com
Title: sirius ufo trickster extraordinaire
Link: https://www.universetoday.com/articles/sirius-ufo-trickster-extraordinaireSource snippet
Universe TodaySirius, UFO trickster extraordinaire23 Mar 2014 — When Sirius is low above the horizon, refraction (bending of light) is st...
-
Source: skyandtelescope.org
Title: sirius ly scintillating holiday12222014
Link: https://skyandtelescope.org/astronomy-blogs/sirius-ly-scintillating-holiday12222014/Source snippet
Sky & TelescopeHave a Sirius-ly Scintillating Holiday!Dec 22, 2014 — Sirius twinkles more than most stars because it's bright, making twi...
-
Source: skyatnightmagazine.com
Title: why do stars twinkle
Link: https://www.skyatnightmagazine.com/space-science/why-do-stars-twinkleSource snippet
?2 May 2025 — Stars appear to twinkle because their light passes through our atmosphere and is bent and distorted by varying temperatures...
Published: May 2025
-
Source: stargazerslounge.com
Title: Stargazers Lounge Why does Sirius sparkle with different colours?
Link: https://stargazerslounge.com/topic/57590-why-does-sirius-sparkle-with-different-colours/Source snippet
Observing23 Jan 2010 — Sirius twinkles because it is so low down to the horizon as seen from the UK. The light from it has to travel thro...
-
Source: Wikipedia
Link: https://en.wikipedia.org/wiki/SiriusSource snippet
SiriusSirius is the brightest star in the night sky, located in the southern constellation of Canis Major. Its name is derived from th...
-
Source: stargazerslounge.com
Title: stars flashing colors
Link: https://stargazerslounge.com/topic/157704-stars-flashing-colors/Source snippet
The Astro Lounge1 Aug 2012 — The twinkle (rather than flash) of stars has to do with scintillation, one of the principle factors wrapped...
-
Source: skyatnightmagazine.com
Title: green flash sirius
Link: https://www.skyatnightmagazine.com/astrophotography/green-flash-siriusSource snippet
Sirius flashes green and twinkles as it sets in smartphone...16 May 2024 — The green flash of Sirius is captured in a composite image an...
Published: May 2024
-
Source: meteorwatch.org
Title: It is very bright, which can amplify atmospheric effects.Read more
Link: https://meteorwatch.org/sirius-twinkle/Source snippet
Sirius - The Multicoloured Star and Why it TwinklesJan 10, 2019 — Sirius appears to twinkle or shimmer more than other stars due to some...
Additional References
-
Source: merriam-webster.com
Link: https://www.merriam-webster.com/dictionary/SiriusSource snippet
SIRIUS Definition & MeaningThe meaning of SIRIUS is a star of the constellation Canis Major that is the brightest star in the heavens —ca...
-
Source: space.com
Link: https://www.space.com/stargazing/the-brightest-star-in-the-night-sky-shows-off-this-spring-how-to-see-a-scintillating-siriusSource snippet
The brightest star in the night sky shows off this spring25 Apr 2025 — The lustrous star Sirius will be putting on its best show for even...
-
Source: facebook.com
Link: https://www.facebook.com/groups/StarAdventurer/posts/3168203500127958/Source snippet
The atmospheric turbulence causes Sirius to twinkle with all the colours of the rainbow.Read more...
-
Source: facebook.com
Link: https://www.facebook.com/groups/AlbertaAuroraChasers/posts/6831445323538761/Source snippet
on it appears to flash bright green and red in the eyepiece of my...Read more...
-
Source: physicsforums.com
Title: why does sirius a blink in many colors.902706
Link: https://www.physicsforums.com/threads/why-does-sirius-a-blink-in-many-colors.902706/Source snippet
Why does Sirius A blink in many colors?5 Feb 2017 — Basically this happens due to atmospheric refraction and to every stars but Sirius is...
-
Source: cloudynights.com
Title: 448822 does sirius flicker or change colors
Link: https://www.cloudynights.com/forums/topic/448822-does-sirius-flicker-or-change-colors/Source snippet
Does Sirius flicker or change colors?15 Jan 2014 — Stellar scintillation and atmospheric prismatic dispersion are responsible for the fli...
-
Source: instagram.com
Link: https://www.instagram.com/reel/DTYdWyLDWLP/Source snippet
color. What you're witnessing is an atmospheric optical illusion...
-
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: instagram.com
Title: The Star that Dances
Link: https://www.instagram.com/reel/DTk57-XDzY8/?hl=enSource snippet
When you point a telescope at Sirius...Earth's atmosphere bends and distorts the starlight as it travels toward us, making Sirius appear...
-
Source: starwalk.space
Title: why do stars twinkle
Link: https://starwalk.space/en/news/why-do-stars-twinkleSource snippet
Why Do Stars Flicker | What Causes Stars to TwinkleSep 23, 2022 — The stars seem to twinkle red and blue due to scintillation – distortio...
Topic Tree