These Mars Photos Were Taken 13 Seconds Apart

In August 2023, NASA's Curiosity rover pointed one of its navigation cameras at a rocky slope on the flank of Mount Sharp and took a routine picture of the landscape, the kind of image it has taken hundreds of thousands of times over more than a decade on Mars. Nobody paid much attention to it at the time, but three years later, that picture started circulating online, and once you see what people noticed in it, you understand why. On the far left of the frame, standing on a ridge, there's a dark shape that looks for all the world like a jellyfish, with a rounded cap on top and a set of ragged tentacles hanging beneath it. Some people say jellyfish, others say it looks like one of the alien tripods from H.G. Wells' War of the Worlds. And here is the detail that makes it strange. Curiosity took another picture of exactly the same scene, with exactly the same camera, just 13 seconds earlier, and in that picture, the jellyfish isn't there. So what happened on a Martian hillside in 13 seconds? The answer turns out to be nothing on Before we get to what this thing actually is, it's worth remembering that Mars has a long history of producing images like this. Over the years, rover cameras have captured what looked like a human face lying in the dust, a bone that resembled a femur, a cluster of mushrooms, and a rectangular opening that was quickly nicknamed the alien doorway. Every one of those turned out to be a rock. Mars is a planet made almost entirely of rocks, and the human brain is an extraordinarily good pattern-matching machine. Show it enough random shapes, and it will eventually find a face, an animal, a door. Astronomers call this pareidolia, but the jellyfish is different from all of those earlier cases. A rock doesn't vanish and reappear. Whatever produced this dark silhouette existed for a single exposure and then was gone, and that points to an explanation that has nothing to do with the surface of Mars, and everything to do with what's raining down on it from space. The evidence is all publicly available, because NASA releases every raw image from Curiosity within hours of receiving it. The jellyfish picture is listed as Sol 3924, the mission's 3,924th Martian day, captured by the Right Navigation Camera at 222746 UTC on 20 August 2023. Curiosity's navigation cameras are a pair of black and white cameras on the rover's mast, used mainly to survey terrain and plan safe drives, and they almost always shoot in sequences. In this case, the same camera photographed the same slope at 222733, 13 seconds before the jellyfish frame, and again about 25 seconds before that. If you put those frames side by side, you see the same rocks, the same ridge, the same sky, in exactly the same positions. The only difference is that the dark shape is present in one image and completely absent from the other two. That's the figure to keep in your mind through the rest of this video, because it settles the most important question right away. Nothing on the surface of Mars appears out of nowhere in 13 seconds. Rocks don't do it, shadows don't do it, and even dust devils leave a trail you can trace across multiple frames. So the shape was never on the hillside, it was inside the camera. To understand what got inside the camera, you need to understand one thing about Mars we take for granted on Earth. Our planet is shielded. Earth has a global magnetic field that deflects a large share of the charged particles streaming in from the sun and from deep space. And the ones that make it through slam into our thick atmosphere, where they break apart into showers of secondary particles high above our heads. Mars has neither of those protections in any meaningful way. It lost its global magnetic field billions of years ago, and its atmosphere holds only about half a percent of the mass of Earth's. So the high-energy particles we call cosmic rays, some of them accelerated by exploding stars on the far side of the galaxy, reach the Martian surface, along with bursts of particles thrown out by flares and eruptions on the sun. Curiosity carries a dedicated instrument to measure all of this, because NASA needs to know what future astronauts would face. But cosmic rays don't only hit radiation detectors. They hit everything, including the silicon sensors inside the rover's cameras. And when a charged particle passes through a camera sensor, it deposits energy into the pixels it crosses, and the image records the strike as a mark that was never in front of the lens. None of this is new to the engineers at NASA's Jet Propulsion Laboratory. Back in April 2014, two Curiosity images with mysterious bright spots went viral, and JPL put out a statement. In the thousands of images received from Curiosity, scientists see ones with bright spots nearly every week. Cosmic ray hits or sunlight glinting off a rock are the most likely explanations. Now, most cosmic ray artifacts look bright, or a spray of speckles, when the particle fluxes high, which is exactly what Curiosity's cameras recorded during a solar storm in 2024. The jellyfish is dark, and that's the one detail that makes the case slightly less tidy. But dark artifacts are documented too. While Mars was passing behind the sun, and the rover sat idle, and NASA's own description of the rear camera footage points out a small black artifact that appears in one frame and attributes it directly to a cosmic ray striking the sensor. So here's where things stand. The Curiosity imaging team hasn't published a formal analysis of this specific frame, and until they do, we can't say with absolute certainty that it was a cosmic ray rather than some other glitch in the camera electronics, or in the compression that images go through before they're transmitted to Earth. What we can say is that every characteristic of the jellyfish fits a sensor event. It lasted exactly one frame. It has an irregular structured outline, which is what you'd expect from a particle passing through the detector at a shallow angle, or triggered a small cascade of secondary particles inside the silicon, leaving a compact head with trailing branches. And it appeared in a place where 13 seconds earlier there was nothing. Mars doesn't need jellyfish to be interesting. The remarkable thing in this story is that the picture exists at all. We have a robot the size of a car, driving across another planet and sending every frame home for anyone to examine, including the glitches. That openness is what makes the pareidolia possible, and it's also what makes the debunking possible, because the neighboring frames are always one click away. Curiosity is still climbing Mount Sharp, and in late August 2026, NASA announced that it had gained a full kilometer of elevation since landing in 2012. Its cameras will keep shooting, and particles from deep space will keep hitting them, and the frames on either side of it will tell exactly the same story. We recently uncovered what's happening deep inside Mars, where the ground itself won't stop shaking. If you missed that episode, it's right on your screen. See you in the next one.