NASA’s Curiosity and Perseverance rovers have photographed some pretty strange objects on the surface of Mars. From human heads and femur-like bones to ‘mushrooms’ and suspiciously geometric structures, these objects are ultimately determined to be something Mars has in abundance. Yes, you got it: rocks. However, in an image taken by Curiosity in 2023, and recently doing the rounds of whether there is life on Mars, the explanation is a little more unusual. At the far left of an otherwise normal image of a Martian landscape is a strange dark shadow that looks a bit like the silhouette of a jellyfish with tentacles dangling downwards or, more appropriately, a Martian tripod straight out of HG Wells’ Planet War. Worlds. Obviously, this feature is not as easy to explain as a rock, but, equally obvious (or it should be), there are no extraterrestrial jellyfish floating in the atmosphere of Mars either. Instead, the mysterious speck likely has a much more cosmic origin: a charged particle falling from space and hitting the silicon detector of Curiosity’s NavCam. A close-up of the failure. (NASA/JPL-Caltech) In fact, there’s an easy way to be pretty sure that whatever we’re looking at isn’t actually a sinister “jellyfish” perched on a Martian ridge. Curiosity routinely takes multiple images of a target, and this is a good illustration of why. The eerie photo of the jellyfish was taken on August 20, 2023 at 22:27:46 UTC. He also took photographs of the exact same scene using the exact same instrument, 13 seconds and 25 seconds earlier. Neither of the two images above show even a hint of a negative space jellyfish. Two frames taken seconds apart. (NASA/JPL-Caltech) It is also not the first time that a strange, fleeting spot appears in one of Curiosity’s images. Cosmic rays are high-energy particles that are constantly falling from space. Here on Earth, we generally don’t have to worry about them: our planet’s magnetic field deflects many, while those that do pass tend to crash into particles in our thick atmosphere, producing showers of secondary particles overhead. Mars is not so well defended. It has no global magnetic field and its atmosphere is only 0.5 percent the mass of Earth, leaving Curiosity comparatively exposed to energetic particles falling from space. Therefore, it is actually not unusual for cosmic ray artifacts to appear in Curiosity images. These charged particles routinely hit the detectors of cameras that operate beyond Earth’s protective magnetic field and atmosphere. When they do, they can leave glitches in the resulting images. In Curiosity photographs, these often look like bright white spots, as if someone had hit the camera from afar with a small laser pointer, or bright white streaks and static specks. They can take a few different forms. “In the thousands of images we’ve received from Curiosity, we see some with bright spots almost every week,” imaging scientist and systems engineer Justin Maki of NASA’s Jet Propulsion Laboratory said in 2014. A similar black artifact caused by a cosmic ray. (NASA/JPL-Caltech)But cosmic ray artifacts don’t have to be bright white, as they are often described. In a video recorded with Curiosity’s Hazcam in 2023, it is observed that a “small black artifact” originates from a cosmic ray that hits the sensor. These events are brief, usually visible in a single frame, exactly the type of behavior observed in Curiosity’s mysterious “jellyfish.” That doesn’t mean we can definitely blame a cosmic ray for this particular appearance. Without analysis by Curiosity’s imaging team, other cameras or processing artifacts cannot be ruled out. Related: Mysterious Structure on Mars Looks Uncannily Like an Ancient Egyptian Pyramid But the images themselves make one thing pretty clear: Whatever produced the jellyfish was almost certainly happening in the camera, not lurking on the surface of Mars. Mars doesn’t need jellyfish, severed heads, or strange pyramids to be interesting. The reason we see those things is pretty interesting: we have robots exploring an other planet on our behalf, one whose geology throws up some crazy rocks and which leaves the explorers sitting ducks for being hit in the head by particles that may have traveled half the cosmos to get there. This article was fact-checked by Michael Irving and edited by Michael Irving. While we take pride in our process, we are human. If you spot an error, please let us know.
