Fallrapport: IR-objekt vid Etna-utbrott 2018

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All-domain Anomaly Resolution Office 
U.S. Department of Defense 
Case: “Mt. Etna Object” 
Case Resolution | 28 April 2025 
Case Synopsis 
Location: Mt. Etna, Italy 
Date: December 2018 
Object Altitude (reported): 500 feet 
Object Altitude (assessed): 15,000 feet 
Object Speed (reported): 345 mph 
Object Speed (assessed): 24 mph 
Object Shape (reported): Round 
Object Shape (assessed): Spherical 
Reporter: U.S. Military UAS operators 
Data Type: Infrared 
Reported Behavior: An object moving at 
high speeds through Mt. Etna’s ash plume. 
Assessed Behavior: The object did not 
demonstrate anomalous performance 
characteristics. 
Confidence: Moderate confidence the object 
was a balloon. High confidence the object did 
not demonstrate anomalous performance 
characteristics. 
AARO Assessment and Case Status 
AARO assesses with moderate confidence 
that the objec t was a balloon. AARO 
assesses with high confidence that the 
object did not exhibit a nomalous behavior. 
Case Overview 
In December 2018, 
a shortwave infrared 
(SWIR) camera onboard a U.S. military 
uncrewed aerial system (UAS) operating 
near U.S. Naval Air Station Sigonella over 
the Mediterranean Sea south of Sicily, 
Italy, 
captured 12 minutes of infrared video 
of an eruption of Mt. Etna. For 
approximately four and a half minutes, a 
round object a ppears on the video and 
seems t o exhibit a nomalous performance 
characteristics by moving at high speeds 
and transiting a superheated gas and ash 
plume produced by the eruption. 
The UAS operator reported that the 
object’
s flight behavior was seemingly 
unaffected by transiting the plume, with no 
d
iscernable impact on its performance, 
altitude, or bearing. The operator reported 
the object’s speed as approximately 555 kph (345 mph). 
Key Findings 
AARO assesses with high confidence that: 
•Optical effects, turbulent atmospheric conditions, and limitations in sensor capability
distorted the o
bject’s apparent behavior, leading to an inaccurate initial assessment of
its performance characteristics.
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•The object did not exhibit anomalous speeds or other behavior exceeding known state-of-
the-art performance characteristics. It did not pass through the volcano’s ash plume.
Performance Characteristics 
Object Speed:
 AARO assessed that
 the object’s speed was approximately 39 kph (24 mph), 
moving generally west-
to-east, consistent with wind speed and direction. The object’s apparent 
high speed is attributable to motion parallax. Motion parallax is an optical effect that induces an 
observer to perceive that a stationary or slow-moving object is moving much faster than its 
actual speed when viewed from a moving frame of reference. The more quickly an observer 
moves relative to an observed object, the more pronounced this effect is. The UAS platform’s 
relative motion made the object appear to move at high speeds. 
Object Flight Path: AARO estimated the object's distance from the UAS platform by 
comparing its speed, the cloud deck’s apparent motion, and the wind speed to plot its trajectory. 
Applying this methodology, AARO created a model that accurately predicted the object’s 
location later in the video, validating the conclusion that the object moved at wind speed and 
heading. (Figure 1) This predictive model aligned 
with the findings of an independent 3-D model 
produced by an AARO partner, further validating the methodology. 
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