The 1977 event that marked a turning point in the history of UAP research in the USSR
| Name | Petrozavodsk Phenomenon |
| Occurred on | September 20, 1977 |
| Seen by | Residents of Petrozavodsk city and its neighboring countries in northern Europe |
| Investigated by | Academy of Sciences of the USSR |
The Petrozavodsk phenomenon is an anomalous event that happened in the early morning of September 20, 1977. Residents of Petrozavodsk city witnessed a bright object in the shape of a jellyfish in the dark sky. This mysterious spectacle was also seen across parts of northern Europe, making it one of the most discussed UFO sightings of the Cold War era.
The phenomenon sparked immediate interest from scientists, governments, and the media. The increasing sensation prompted the Academy of Sciences of the USSR to initiate a formal investigation and publish a preliminary report.
Now, decades have passed, and the Petrozavodsk phenomenon remains a subject of debate in the UFO community.
What Is the Petrozavodsk Phenomenon?
Between 3:00 AM and 6:00 AM Moscow time on September 20, numerous residents across the Soviet-Finnish border witnessed something unlike any natural or celestial event. The eyewitnesses included “workers of a first-aid unit, on-duty employees of the militia, seamen and the longshoremen at Petrozavodsk’s port, military, local airport staff, and even an amateur astronomer.”
According to a TASS news report, a huge mass of light appeared in Petrozavodsk and hovered above it. It was emitting beams of light to the ground, similar to a downpour of rain, making it look like a jellyfish. When it stopped, the “jellyfish” became a bright half-disk and flew in the direction of Lake Onega. This spectacle lasted for 10–12 minutes.
With many people serving as witnesses, it became impossible to ignore the fact that it happened. The Academy of Sciences and newspapers received numerous letters from the public demanding an explanation. Even government officials from neighboring countries sent letters, worried that it might be caused by Soviet weapons testing and that it might pose dangers to the region.
What followed was one of the most extensive official investigations into a UAP in Soviet history. Over time, this event, which was once simply called the “September 20, 1977 phenomenon,” became known as the Petrozavodsk phenomenon. Soviet scientists and researchers also used the term “anomalous phenomenon” instead of “UFO,” as it fit the context of what they were doing.
When and Where Did the Petrozavodsk UFO Appear?
The Petrozavodsk phenomenon wasn’t a single, confined sighting. It unfolded over hours and spanned multiple countries.
The sighting descriptions below, which are taken from the Academy of Sciences’ preliminary report, are translated using Google Translate and DeepL Translate. If you think there have been translation inaccuracies in our understanding of the data, please let us know—we highly appreciate it!
The Phases of the Sightings
According to the preliminary report, organizing the timing of events was complicated due to the time zone differences between countries. What was known, though, was that the Petrozavodsk UFO was observed from 3:00 AM to 6:00 AM Moscow time. With that serving as the basis, the investigating team segmented the phenomenon into three phases to “somehow understand the events” that took place.
| Phase | Time Occurred | Sighting Description |
| Phase I | 3:00 AM to 4:00 AM | One or more luminous bodies were observed flying by at different points at different times |
| Phase II | 4:00 AM to 4:15 AM | These were observed at almost all points simultaneously: – The appearance of a luminous object – The development of a translucent shell around it – The appearance of a radiant structure – The subsequent departure of the object with a change in direction by almost 180° |
| Phase III | 4:15 AM until dawn | A stable, intense glow was observed near the horizon, which lasted until dawn |
*”Points” refer to locations in this context.
From the descriptions, we can infer that the observed sighting in Phase II was what most eyewitnesses had seen. It also corroborated the description Nikolai Milov had written in his TASS news story.
The Geographic Spread of Sightings
The same report found that the primary location where the Petrozavodsk UFO was observed was the northwest regions of the USSR and Europe.
Karelia, USSR
Observation Point: Petrozavodsk (Epicenter)
Observers: On-call ambulance crews, police officers on duty, cargo port workers, G.P. Safronova (a researcher at the Institute of Geology), V.I. Barkhatov (a former pilot), and other city residents.
At 4:00 AM Moscow time, a bright object appeared in the northeastern sky below Ursa Major. It had a small, Venus-like core surrounded by a translucent shell.
One observer, Barkhatov, noted a fainter second point behind it and a visible trail, similar to that of a jet.
The object ascended from east to west, which had a course angle of about 240°, expanding into a large, glowing cloud with a diameter of about 30°. Some compared it to a parachute or jellyfish, with glowing threads and curved rays extending from the center.
The glow was white-blue, with a red central object. At its peak, the cloud lit up the surroundings like a full moon and reached an elevation of 30°–40° before dissipating.
Bright points briefly appeared along its lower edge. A dark spot then formed at the center, the glow faded, and the core rapidly moved northward with a course angle of about 30°.
The entire event lasted 10–15 minutes.
Observation Point: Namoyevo
Observer: Yu. V. Linnik
A luminous object flew overhead at 3:00 AM. Grabbing his telescope, Linnik found that the object consisted of a lens-shaped central body surrounded by a matte translucent ring.
The lens-shaped body was the color of “dark amethyst, intensely illuminated from within.” At its edges were 16 points from which pulsating rays of red color diverged at an angle of 10°–15° to the plane of the disk.
Linnik followed the object’s trajectory as it moved from east to west across the stars.
This lasted for 15 minutes.
Observation Point: Kurkijoki
Observer: Engr. A.P. Novozhilov (Institute of Limnology of the Academy of Sciences)
Around 4:15 AM, Novozhilov saw what first appeared to be a meteor. Instead of falling, it stopped and moved toward him, growing in size and revealing a shape like an elongated airship.
The object had six or eight glowing ribs connecting two bright end spots, with softly lit panels between them resembling windows covered by sheer curtains. It flew silently at an altitude of about 300–500 meters, approximately 100 meters long and 12–15 meters wide.
As it passed overhead, a glowing white ball emerged from its rear and flew north, descending behind a forest and lighting up the area as it landed. Novozhilov took three photographs, but none developed.
The entire sighting lasted 10–15 minutes. The object moved at the speed of a helicopter.
Novozhilov later felt unwell and fainted multiple times over the next few days.
Murmansk, USSR
Observation Point: Kovdor
Observer: PGI engineer A.K. Dudakov
Around 3:00 AM, a bright point of light appeared in the eastern sky, about 45° above the horizon, moving upward from east to west. It quickly developed a wide, fan-shaped tail that grew to 180° as it crossed near the top of the sky.
When it moved slightly west of the zenith, a second, dimmer point appeared behind it. The object then shifted direction toward the northwest.
The first point faded, while the second became brighter and turned into a faint glowing spot. It moved more slowly, increasing the gap between them, and eventually faded along with the tail.
There were no clouds or auroras present as the event happened.
Chelyabinsk, USSR
Observation Point: Troitsk
Observer: Yu. Novoktonov
At 3:50 AM Moscow time, a glowing sphere about the size of the moon was seen moving slowly west to east, leaving an orange trail like an aircraft contrail. Its edges were blurry, and a visible arc formed around its front half. The sphere flickered and emitted rays in all directions except in front of the arc.
It appeared to be flying low in the atmosphere, as its trail was seen against the clouds. At one point, it seemed to stop and grew into a glowing cloud. A smaller sphere emerged from this cloud, continued east, and turned into a bright red spot as it entered the clouds.
Leningrad, USSR
Observation Point: Leningrad Sea Trade Port
Observer: Port supervising staff
A luminous body appeared from 3:00 AM to 3:25 AM.
Observation Point: Pulkovo Airport
Observers: Airport night shift employees B.N. Blagirev, V.I. Rodionov, and S.V. Sergeev
At 3:55 AM, B.N. Blagirev saw a fireball in the north-northeast at 20° elevation. Surrounded by a luminous, structured shell, the sphere emitted bright, rhythmic light in all directions, unlike auroras. The object moved in an arc toward the observer, then reversed course sharply and retreated north-northwest. Its shell continued expanding after the reversal, and the object disappeared by 4:07 AM.
V.I. Rodionov saw a similar sight around the same time. The light reached near-daylight brightness at peak elevation (70°–80°) before fading and vanishing north-northwest by 4:08 AM.
S.V. Sergeev observed rhythmic light from the object starting at 4:00 AM. At 4:05, the fireball disappeared, replaced by a dark, geometrically shaped spot. The object then moved north-northwest and vanished by 4:09 AM.
Observation Point: Lakhta
Observer: V.D. Kozlov
At around 4:00 AM, while working at a construction site near Lakhta, Kozlov observed a fireball low in the northeastern sky. It was about one-third the size of the moon.
Suddenly, bright, colorful rays began radiating from the sphere in a fan-like pattern. The rays pulsed outward in short bursts, forming a large arc that gradually lit up the northeastern part of the sky over Leningrad.
The sphere appeared to hover in place, sometimes hazy, other times clearly visible, like the sun or moon behind thin clouds. This lasted for 3–4 minutes. Then the sphere faded away, while the rays remained for a time, slowly spreading and dimming. The display featured vivid reds, with yellow, blue, and smoky shades.
Finland
Observation Point: Helsinki
Observers: Taxi drivers, police officers, and airport staff
A glowing ball was seen over Helsinki. Police near the stadium first reported it, and multiple patrols then tracked the object as it moved north, leaving a smoky trail. Taxi drivers said it was so bright it lit up their booths.
At 4:07 AM Moscow time, a flight director at Helsinki-Vantaa Airport saw a light arc in the east. The object moved, then suddenly stopped and “exploded” like fireworks, creating a fan of light toward the ground. A bright point then continued moving north.
Witnesses gave varying accounts of its direction, and the event lasted about 10 minutes. The object was reportedly not seen on radar. That night, bright auroras were also observed.
Observation Point: Turku
Observers: Two unnamed men
At 4:10 AM Moscow time, while driving through the outskirts of Turku toward Topik Øya, two men spotted a strange rotating light in a field about 300 meters away. Curious, they got closer and approached the object. It was shaped like a lifebuoy, about 10 meters in diameter, and surrounded by a haze or fog. Inside, there appeared to be a light or fire.
Moments later, the object rose and began moving toward them. Alarmed, the men ran back to their car. As they drove away, they saw the object ascend further and disappear into the night sky.
Estonia
Observation Point: Tallinn
Observer: Harbor watchman A. Murnikov
At around 4:00 AM, an oval-shaped semicircle appeared on the northeastern horizon. It measured approximately 10°–15° in angular size and remained visible until nearly sunrise.
What Evidence Was Collected at the Time?
Aside from the eyewitness statements, which took up a bulk of the evidence, the Academy of Sciences also looked at the following:
Eyewitnesses’ Psychological Conditions
Clinical psychologist E.K. Andreeva interviewed and examined nine people who reported seeing the Petrozavodsk UFO. The group consisted of teachers, electricians, a dispatcher, a doctor, and other professionals. Among them, Yu. V. Linnik’s account stood out for its accuracy and depth.
All nine shared how they felt surprised or anxious as they were witnessing the event. Despite that, they didn’t experience any lasting psychological effects after seeing the jellyfish-like object. They remained clear-minded and slept normally.
Throughout the examination, Andreeva noted that they were honest and objective in their statements. This led her to conclude that their testimonies were sound, grounded, and credible.
Environmental Anomalies
The Academy of Sciences wanted to see if the Petrozavodsk phenomenon had left an environmental impact on Lake Onega, including Petrozavodsk Bay. So, with the aid of researcher Sergey Semenovich from the All-Russian Scientific Research Institute, they conducted tests to measure the lake’s radioactivity levels.
The result was negative.
- The radioactivity of Lake Onega remained stable from 1973 to 1977, with no detectable changes in its levels.
- Water in Petrozavodsk Bay, measured at a depth of one meter, had the same radioactivity level as the rest of the lake. There were no signs of contamination at all.
- Further analysis was needed to finalize data on soil radioactivity and detector background levels.
Radar Observations
Unlike the first two, the radar data had conflicting reports.
The report initially referenced by UPI claimed that the Helsinki-Vantaa Airport radar had detected the Petrozavodsk UFO. However, the airport’s flight director, Ari Hyämäläinen, denied this claim.
The Pulkovo Airport in Leningrad, the Peskov Airport in Petrozavodsk, and the air defense forces also reported that they didn’t detect anything unusual at that time.
However, meteorological radar in Petrozavodsk did record unusual radar signatures on three separate dates:
- September 30. A fast object (~1500–1800 km/h) was seen 16 km from the city, much larger than a TU-134 plane.
- October 20. A slow-moving object was visually observed and detected on radar at a distance of approximately 21 km, but its identification was uncertain.
- November 20. Two “strip-shaped” objects moved together at a distance of approximately 240 km and disappeared simultaneously.
Astronomical, Geophysical, and Meteorological Conditions
The investigative team found that the Petrozavodsk phenomenon occurred during a period of geomagnetic and atmospheric disturbance.
- September 16–19. Solar flares were recorded.
- September 15–18. The magnetosphere was calm.
- September 19–21. The magnetosphere was moderately disturbed.
- September 19, 2 PM Moscow time. SSC-type magnetic storms were recorded.
- September 20, 4 PM Moscow time. A strong magnetic storm with several substorms was recorded, with instrumental readings going off the scale.
- September 17–18 and 19–21. Two intense proton intrusions of the solar cosmic rays were recorded, likely triggered by the solar flares on September 16–19.
- September 20, 3:00 AM to 12:00 AM Moscow time. The maximum proton flux was observed, aligning with the time of the event.
They found that the proton intrusions triggered the auroras that were seen in Karelia on the night of September 19–20; in Sortavala two hours before the Petrozavodsk phenomenon; and in Lekhta during the event itself.
Weather Conditions
It was found that the weather conditions on September 20 were all within the influence of a dominant or extratropical cyclone system. The eyewitnesses’ accounts of the weather at the time matched well with the official meteorological data, too.
The weather over Karelia and Leningrad was shaped by a large, stable cyclone centered over the Kara Sea, with smaller fast-moving cyclones passing through, causing sharp weather changes. Here are the observations at 3 PM Moscow time recorded in the report:
- The weather in the surface layer (atmospheric layer is less than 700 meters)
- Petrozavodsk. The snow ended and had mostly clear skies, with only 1/4 cloud cover.
- Sortavala. The weather was already clear.
- Lekhta. The sky had 3/4 cloud cover, but it was expected to clear shortly due to the northerly wind blowing at approximately 5 m/s.
- Kemi. The sky was still cloudy after the rain and snow.
- Primorsk, Leningrad, and nearby towns. They had overcast skies, but clearer weather was approaching from the north.
- Pskov and the Baltic states. The skies began to clear or were already clear.
- The weather in the upper atmosphere (atmospheric layer is equal to or more than 700 meters)
- Throughout Finland, Karelia, and Leningrad
- Strong air current moved from north to south up to a latitude of 60°.
- Once it came south, it shifted direction westward.
- Wind speed increased with altitude.
- At 1.5 km, winds reached 70 km/h (N) and 60 km/h (W).
- At 7–9 km up to 12–13 km, winds reached 180–190 km/h.
- At 20 km, wind speed began to drop.
- At 24 km and above, there were weak westerly winds again.
- Throughout Finland, Karelia, and Leningrad
Though the northwestern regions of the USSR and Europe were experiencing unstable, rapidly changing weather at the time, conditions began to clear from north to south just before the phenomenon occurred.
What Are the Leading Explanations for the Petrozavodsk UFO?
In their report, the Academy of Sciences was unable to come up with a definitive answer due to incomplete data. However, it didn’t stop others from giving competing explanations about what, how, and why of the Petrozavodsk phenomenon.
From the Academy of Sciences
The investigative team stated that “the scale of the phenomenon was apparently too great to be explained by technical experiments in satellite orbits. Perhaps there was an impact of some cosmic factor, but we still know nothing about its nature.”
Nevertheless, they did provide the government, the media, and the public with a general picture and a preliminary data analysis. They also considered three hypotheses, which were:
- The successive passage of a single object through the observation points.
- The passage of a single object over a specified area (or near it) at a sufficiently high altitude to allow simultaneous observations from all points.
- The passage of several objects of the same type at approximately the same time (with an accuracy of several minutes).
The first was ruled out because the Petrozavodsk UFO was observed simultaneously at all points.
The second could explain how the object was seen from all points at the same time, if it was flying at an altitude of around 100 km or higher. In that case, the object would need to be at least one km wide, and the surrounding shell would be several tens of kilometers across.
The third was the most likely explanation as it can back the full set of observed data. Based on this idea, the following model could be considered:
- Object N1 passed near Helsinki and, moving northeast, was seen a few minutes later in Lehta.
- Object N2 flew near Leningrad, changed direction after briefly stopping, and then moved north. It was also seen a few minutes later in Lehta.
- Object N3 flew at a low altitude near the Podporozhye and Petrozavodsk stations, moving north or northeast. After stopping over Petrozavodsk and discarding its outer shell, it moved toward the north-northwest and was later observed in Lekhta.
Of course, these were only speculations. The sighting reported in Lepiasurya couldn’t fit into them, making it difficult to explain.
Other Stand-Out Explanations
Kosmos-955 Satellite Launch
One of the most persistent explanations linked the event to the launch of Kosmos-955 from Plesetsk Cosmodrome on September 20, 1977.
Space analyst James Oberg argued that the “jellyfish” effect was consistent with a predawn rocket launch4, where exhaust plumes expand in the upper atmosphere and catch sunlight, creating striking shapes. Yuli Platov later supported this view, noting similar “space jellyfish” sightings after other launches near dawn or dusk.
However, Soviet astronomer Lev Gindilis and others pointed out inconsistencies: the observed westward motion didn’t align with the satellite’s northeast trajectory, and reports from multiple locations began before the launch.
Military Testing
Some researchers suggest that what witnesses saw was linked to a failed or experimental military test. Later, Soviet and Western sources mentioned the possibility of a ballistic missile test in the region around the same time.
According to one review, several unusual effects attributed to the phenomenon were likely caused by such a failed launch. This hypothesis aligns with the secrecy surrounding Plesetsk, a military spaceport whose existence was officially denied at the time, and with later references to Soviet programs studying the impact of “anomalous atmospheric phenomena” on equipment and personnel.
Natural Phenomenon
Some scientists proposed that the Petrozavodsk phenomenon was due to atmospheric causes.
Vladimir Krat of the Pulkovo Observatory suggested it was a meteorite, though later shifted to an aurora explanation. Vladimir Migulin of IZMIRAN also thought it was the aurora. However, Felix Ziegel challenged this view as auroras don’t occur at such low altitudes and are far less bright than what witnesses described.
A more unusual explanation came from M. Dmitriyev, who proposed that it was a form of atmospheric chemiluminescence. However, critics argued that the energy levels involved were too weak to match observations.
Extraterrestrial in Nature
Not all researchers accepted technical or natural explanations.
Paul Stonehill, a UFO researcher, argued that the official “satellite launch” story was more of a cover than an answer. He pointed to reports of unusual moods among people before the event, long traditions of UFO sightings in northern Russia, and the fact that the Soviet Union responded with serious classified studies, something that would seem excessive if the cause was merely a satellite.
Why Does the Petrozavodsk Phenomenon Still Matter Today?
Even though it remains unexplained to this day, the Petrozavodsk phenomenon became the trigger for the Soviet Union to consider UAPs as cases that necessitate serious scientific inquiry.
It prompted the government, through the Academy of Sciences of the USSR, to gather eyewitness accounts, do field investigations, and consider angles to find evidence that could help them explain what happened. Such actions made the phenomenon one of the most well-documented UAP cases in history. Case in point: the science-based investigations the investigative team put into their report.
As interest in UAP grows worldwide, the Petrozavodsk phenomenon serves as a historical case study in how the government and scientists respond to the unexplained and how mystery can endure despite decades of scrutiny.
Want to dive deeper into UAP history and current sightings? Explore more UFO content on UFO Connect.
FAQ
What did eyewitnesses report seeing?
Eyewitnesses described the Petrozavodsk UFO as a jellyfish in the sky, luminous orbs or spheres, cylinders, and clouds. Despite the variety of descriptions, their accounts were broadly consistent: bright, structured, silent objects that lingered in the sky before fading. Even the Academy of Sciences noted in their report that the eyewitness testimonies were “mutually consistent and complementary.”
What did the Soviet government do following the Petrozavodsk phenomenon?
The Petrozavodsk phenomenon triggered the government, through the Military-Industrial Commission, to create two UFO research commissions to study the anomalous atmospheric phenomena. One is Setka-AN for the Academy of Sciences, and the other is Setka-MO for the Ministry of Defense.
References
- Boris Sokolov and Yulii Platov. “A History of State UFO Research in the USSR.” Skeptical Inquirer, https://skepticalinquirer.org/newsletter/history-of-state-ufo-research-in-the-ussr/. Accessed September 8, 2025.
- “Soviet Sky Puzzle: ‘Jellyfish’ of Light.” New York Times Archive, https://www.nytimes.com/1977/09/23/archives/long-island-opinion-soviet-shy-puzzle-jellyfishof-light.html. Accessed September 8, 2025.
- L.M. Gindilis and Yu.K. Kolpakov. “Petrozavodsk Phenomenon.” Astronet, http://www.astronet.ru/db/msg/1169491/index.html. Accessed September 9, 2025.
- “Soviet UFO Due to Secret Launch.” ScienceNews, https://www.sciencenews.org/archive/soviet-ufo-due-secret-launch. Accessed September 16, 2025.
- Margeaux Sippell. “What Was the Petrozavodsk Phenomenon, the Jellyfish-Shaped UFO Seen Over Russia in 1977?” MovieMaker, https://www.moviemaker.com/petrozavodsk-phenomenon-jellyfish-shaped-ufo-russia-1977/. Accessed September 16, 2025.
