A previously overlooked photo captured by NASA’s Curiosity rover on August 20, 2023, features an unusual dark shape resembling a “jellyfish” sitting atop a distant Martian hill, according to data shared on social media and analysis from space commentators. While the low-resolution navigational camera image has sparked online debate over whether the anomaly represents a genuine Martian phenomenon or an imaging artifact, experts point to technical glitches as the most probable cause.
Curiosity Rover Spots an Unusual “Jellyfish” on Mars
The anomaly first drew widespread public attention when Kari Sivertzen posted the image on X on August 12, 2026, highlighting a small, dark formation that appears to rest on a rocky ridge inside Gale Crater. According to NASA and JPL-Caltech mission records, the raw grayscale image was originally acquired by Curiosity’s right navigation camera during sol 3924. The shape spans approximately 15 pixels, showing downward-extending dark features that resemble tentacles touching the surface of the hill.
https://x.com/KariSivertzen/status/2087443382469538198
However, images captured by the same navigation camera less than two minutes earlier did not show the shape. Furthermore, an additional image taken by the rover approximately 78 minutes later revealed that the object had completely vanished. This absence in subsequent frames confirms that the formation is not a permanent fixture of the Martian landscape, according to space analyst Amit Surti writing on Medium.
Imaging Artifacts and Cosmic Ray Explanations
Because the shape appears transient, researchers are evaluating several technical explanations for the anomaly rather than physical ones. One primary hypothesis suggests the shape is a cosmic ray artifact, a phenomenon frequently documented by both the Curiosity and Perseverance rovers.
According to analysis shared by Amit Surti on Medium, charge diffusion—the physical movement of charge along a detector’s pixel columns—combined with specific readout directions can produce thin, downward-pointing extensions from a dark core. This process creates a jellyfish-like silhouette. Because such particle interactions are momentary, the resulting artifact typically appears in only a single exposure, matching the behavior of the August 2023 anomaly. A similar shape was previously recorded in a navigation camera image during sol 3613 in 2022.
Pro Tip: When analyzing raw planetary rover data, always check consecutive frames. Transient pixel anomalies typically disappear within minutes, distinguishing them from actual surface features or geological changes.
Electronic and Transmission Glitches
Alternative explanations point to electronic noise or data transmission errors between Mars and Earth. Pixel values can alter during multiple stages of the imaging pipeline, including readout electronics inside flight computers, onboard data compression, downlink transmissions, or ground processing systems.
Specific failure modes identified in planetary imaging systems include temporary pedestal drift in camera electronics, single-event upsets in image buffers caused by radiation, and localized dark-current surges triggered by temperature spikes from nearby rover hardware. Additionally, packet loss during transmission can generate empty dark blocks, while minor mismatches in flat-field calibration files can leave regional residuals. These factors can independently generate isolated dark formations that mimic physical objects without leaving permanent traces in subsequent telemetry.
Transient Phenomena and Historical Context
The difficulty of evaluating isolated visual anomalies highlights the limitations of relying on single, low-resolution exposures without corroborating scientific data. Planetary scientists note that similar imaging glitches will likely continue to surface as rovers stream high volumes of navigational data back to Earth.
The public fascination with unexpected shapes also mirrors historical discussions surrounding Unidentified Anomalous Phenomena (UAP). Observers have occasionally compared atmospheric and space anomalies to biological forms, such as the jellyfish-like object documented over a U.S. joint operations base in Iraq in 2018, or a floating formation observed over the Atlantic on January 1, 2020.
Did You Know? NASA’s Curiosity rover uses dual navigation cameras mounted on its mast to assist with hazard avoidance and route planning, capturing thousands of raw grayscale frames that are frequently scoured by citizen scientists for anomalies.
Frequently Asked Questions
What is the Mars “jellyfish” image?
The image is a raw grayscale photo captured by NASA’s Curiosity rover on August 20, 2023, showing a tiny 15-pixel dark shape on a distant hill.
Is the “jellyfish” a living organism on Mars?
No. According to mission analysts, the shape vanished within 78 minutes and is widely considered to be an imaging artifact, such as a cosmic ray hit or electronic glitch.
Why did the image take years to go viral?
Although captured in 2023, the raw navigational photo was largely overlooked until user Kari Sivertzen shared it on X in August 2026.
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