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- A previously overlooked photo from the Curiosity rover<\/strong> shows an odd \u201cjellyfish\u201d on Mars. Is it a real anomaly or an imaging artifact?<\/li>\n
- The \u201cjellyfish\u201d is a small, dark shape<\/strong> that looks like it is sitting on top of a distant rocky hill.<\/li>\n
- There are various possible explanations,<\/strong> but some kind of imaging artifact is the most likely.<\/li>\n<\/ul>\n
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The \u2018jellyfish\u2019 on Mars<\/h3>\n
The rovers on Mars sometimes see things that look really odd. Typically, it\u2019s weird rocks or other surface features. But sometimes it\u2019s in the sky. Those usually turn out to be pixel artifacts or other glitches in the cameras. And there\u2019s a new case that\u2019s going viral on social media. The image is from the Curiosity rover, in Gale crater, and is actually from August 20, 2023 (sol 3924 for the rover).<\/p>\n
But it was largely overlooked until Kari Sivertzen posted it on X on August 12, 2026. The image shows what looks like a \u201cjellyfish\u201d shape in the distance. The \u201ctentacles\u201d look like they are touching the top of a rocky hill. What is it really?<\/p>\n
![\"Fuzzy](\"https:\/\/earthsky.org\/upl\/2026\/08\/jellyfish-Curiosity-rover-Mars-wider-view-August-20-2023.png\")
A wider view of the terrain in the \u201cjellyfish\u201d image from August 20, 2023. Image via NASA\/ JPL-Caltech.<\/figcaption><\/figure>\n Object or imaging artifact?<\/h3>\n
It looks intriguing, so what is this mysterious \u201cjellyfish\u201d? Notably, images that Curiosity took less than two minutes earlier, looking in the same direction, didn\u2019t show the odd shape.<\/p>\n
The original image is a raw, grayscale image, so not the highest resolution. And the shape only covers about 15 pixels, so quite tiny. The image is from Curiosity\u2019s right navigation camera. The same camera then took another image about 78 minutes later and the shape was gone.<\/p>\n
Theories about the \u2018jellyfish\u2019 on Mars<\/h3>\n
Since the shape is absent in subsequent images, that shows it is not a permanent feature of the landscape. With that in mind, there are a few theories, as also mentioned by Amit Surti on Medium<\/em>.<\/p>\n
The possibilities include a cosmic ray artifact, an electronic or transmission artifact and what astronomers would call a transient physical phenomenon.<\/p>\n
Cosmic ray artifact?<\/h3>\n
Firstly: could the \u201cjellyfish\u201d be a cosmic ray artifact? Both the Curiosity and Perseverance rovers have seen many of these before. As Surti described on Medium<\/em>:<\/p>\n
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Curiosity\u2019s cameras operate in a high-radiation environment. High-energy particles known as cosmic rays constantly bombard CCD detectors in space. When a cosmic ray strikes the silicon grid during a calibration step called a bias frame, it deposits a localized charge. The camera\u2019s processing pipeline later subtracts the bias measurement from the actual exposure. That subtraction converts the bright charge from the particle strike into a dark residual imprint.<\/p>\n
The physical movement of charge along the detector\u2019s pixel columns, a process called charge diffusion, combined with the specific readout direction, could produce thin downward-pointing extensions from that dark core. That would explain the jellyfish shape. And because the interaction is momentary rather than persistent damage, the artifact would appear in only one exposure.<\/p>\n<\/blockquote>\n
A similar shape was also seen in a navigational camera image in 2022, sol 3613. It\u2019s a compelling explanation, but we\u2019d need complete engineering logs to confirm it or not.<\/p>\n
- The \u201cjellyfish\u201d is a small, dark shape<\/strong> that looks like it is sitting on top of a distant rocky hill.<\/li>\n