A Rock That Fooled the Internet
When a sharp-edged structure appeared in NASA’s photos of Mars, amateur stargazers believed they had found proof of alien architecture. The image, taken by the HiRISE camera aboard the Mars Reconnaissance Orbiter, showed what looked like a perfect monolith rising from the Martian ground, eerily reminiscent of the alien structures in Stanley Kubrick’s 2001: A Space Odyssey. The photograph quickly went viral, reigniting debates about life beyond Earth.
How the Image Was Taken
The HiRISE camera, orbiting about 300 kilometers above Mars, captures images at a resolution of roughly 30 centimeters per pixel. That precision is enough to reveal large boulders but not the smaller curves or textures on their surfaces. Jonathon Hill, a researcher at Arizona State University’s Mars Space Flight Facility, explained that when a photo lacks resolution, rounded edges appear squared because the pixels themselves are square. The “monolith” effect, he said, was an illusion created by image resolution and lighting.
Nature’s Geometry on Mars
The rock’s position also offered clues. It sat at the base of a cliff littered with other debris, suggesting it had broken off and tumbled down long ago. Hill noted that its height seemed exaggerated because it was photographed with the sun low on the horizon, casting an elongated shadow. The word monolith is technically accurate—it means “one stone”—but this particular one was neither placed nor sculpted by any intelligence. It was simply nature’s handiwork, shaped by time, erosion, and coincidence.
The Phobos Mystery
Mars’s moon Phobos has a similar story. In 1998, NASA’s Mars Global Surveyor photographed a large boulder, about 85 meters across, standing out from the cratered surface. Astronaut Buzz Aldrin even suggested in a 2009 interview that humanity should visit the “monolith” before returning to the Moon. Scientists later concluded that it was a rock ejected by the impact that formed Stickney Crater, a feature that covers nearly half the moon’s surface.
What the Scientists Saw
Alfred McEwen, principal investigator for the HiRISE team, explained that rectangular boulders are common across planets. Sedimentary layering and tectonic fractures often produce right-angle planes that break into geometric blocks. As for the public’s fascination, researchers attribute it partly to pareidolia, the tendency to see familiar shapes in random patterns.
A Case Closed
Both the Martian and Phobos “monoliths” are entirely natural. The mystery arose not from alien design but from the limits of human perception and photography. Yet these rocks, captured by orbiters circling worlds millions of kilometers away, continue to captivate imaginations as reminders of how strange—and familiar—other planets can appear through a lens.
When a sharp-edged shape appeared in NASA’s photos of Mars, it sparked a wave of excitement.
The image showed what looked like a perfect monolith rising from the red dust, straight out of Kubrick’s 2001: A Space Odyssey.
But the truth behind it was far less mysterious…🧵👇 pic.twitter.com/x0VMuoqEd2
— Fascinating True Stories (@FascinatingTrue) November 2, 2025