Why Sirius So Often Looks Like a UFO

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.orgUpdates 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

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.orgUpdates 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[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.orgUpdates 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[Earth Sky]earthsky.orgUpdates 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 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.orgUpdates 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[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:

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/UFOsWhat 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[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:

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.orgUpdates 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[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:

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…Published: May 2025

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.orgUpdates 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[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…

Amazon book picks

Further Reading

Books and field guides related to Why Sirius So Often Looks Like a UFO. Use these as the next step if you want deeper reading beyond the article.

Book

The UFO Experience

By Joseph Allen Hynek

Discusses common celestial sources of UFO reports.

See on Amazon

Book

NightWatch

By Terence Dickinson

Helps identify Sirius and understand its appearance.

See on Amazon

Book

Turn Left at Orion

By Guy Consolmagno, Dan M. Davis

Useful for locating and identifying bright stars such as Sirius.

See on Amazon

Book

Cosmos

By Carl Sagan

Provides broad astronomical context.

See on Amazon

Browse more on Amazon: The UFO Experience NightWatch Turn Left at Orion

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Endnotes

1. Source: earthsky.org
Link:https://earthsky.org/brightest-stars/sirius-the-brightest-star/

2. 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/

3. Source: earthsky.org
Title: the skys brightest star sirius before dawn
Link:https://earthsky.org/tonight/the-skys-brightest-star-sirius-before-dawn/

4. Source: earthsky.org
Link:https://earthsky.org/todays-image/photo-sirius-in-many-colors/

5. Source: reddit.com
Title: What is this??: r/UFOs
Link:https://www.reddit.com/r/UFOs/comments/1k3wguz/what_is_this/

Published: April 20, 2025

6. 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/

7. Source: reddit.com
Link:https://www.reddit.com/r/Astronomy/comments/1aw3slg/does_sirius_always_flicker_this_much/

8. Source: earthsky.org
Title: flashing star autumn capella arcturus sirius
Link:https://earthsky.org/astronomy-essentials/flashing-star-autumn-capella-arcturus-sirius/

9. Source: earthsky.org
Link:https://earthsky.org/

Published: May 15, 2026

10. 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/

11. Source: astronomy.com
Title: simply scintillating
Link:https://www.astronomy.com/science/simply-scintillating/

Published: May 2023

12. Source: universetoday.com
Title: sirius ufo trickster extraordinaire
Link:https://www.universetoday.com/articles/sirius-ufo-trickster-extraordinaire

13. Source: skyandtelescope.org
Title: sirius ly scintillating holiday12222014
Link:https://skyandtelescope.org/astronomy-blogs/sirius-ly-scintillating-holiday12222014/

14. Source: skyatnightmagazine.com
Title: why do stars twinkle
Link:https://www.skyatnightmagazine.com/space-science/why-do-stars-twinkle

Published: May 2025

15. 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/

16. Source: Wikipedia
Link:https://en.wikipedia.org/wiki/Sirius

17. Source: stargazerslounge.com
Title: stars flashing colors
Link:https://stargazerslounge.com/topic/157704-stars-flashing-colors/

18. Source: skyatnightmagazine.com
Title: green flash sirius
Link:https://www.skyatnightmagazine.com/astrophotography/green-flash-sirius

Published: May 2024

19. Source: meteorwatch.org
Title: It is very bright, which can amplify atmospheric effects.Read more
Link:https://meteorwatch.org/sirius-twinkle/

Additional References

20. Source: merriam-webster.com
Link:https://www.merriam-webster.com/dictionary/Sirius

21. 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-sirius

22. Source: facebook.com
Link:https://www.facebook.com/groups/StarAdventurer/posts/3168203500127958/

23. Source: facebook.com
Link:https://www.facebook.com/groups/AlbertaAuroraChasers/posts/6831445323538761/

24. 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/

25. 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/

26. Source: instagram.com
Link:https://www.instagram.com/reel/DTYdWyLDWLP/

27. Source: facebook.com
Title: You can see it changing colours in real
Link:https://www.facebook.com/groups/AstronomyNo1/posts/5192188810826159/

28. Source: instagram.com
Title: The Star that Dances
Link:https://www.instagram.com/reel/DTk57-XDzY8/?hl=en

29. Source: starwalk.space
Title: why do stars twinkle
Link:https://starwalk.space/en/news/why-do-stars-twinkle