Scientists have been searching for water and evidence of life on Mars for decades, but the planet has become known for strange shapes spotted in its rocky landscapes.
It was a helmet-shaped rock captured by Nasa’s Perseverance rover that sparked alien conspiracy theories this month. The sighting was part of Martian illusions that have, over the years, conjured images of faces, spoons and what looked like a doorway carved into a cliff.
“Most odd-looking features have simple explanations such as shadows, erosion and camera angles,” said Dr Dimitra Atri, principal investigator at NYU Abu Dhabi’s space exploration laboratory.
“But occasionally they reveal new geological processes we hadn't considered. Mars keeps surprising us, which is why we keep looking.”
Long history of strange sightings
The fascination with Martian illusions stretches back to 1976, when Nasa’s Viking 1 spacecraft photographed a rocky formation on the Red Planet that resembled a human face.
The sighting was one of the most memorable “discoveries” of the space age, inspiring books, documentaries and theories about alien civilisations.
When the Mars Global Surveyor returned to the site in 1998 with a sharper camera, the “face” was revealed to be merely a rocky hill, with the human-like "features" created by lighting and shadows. But by then the idea of hidden structures on Mars was already part of popular culture.
Since then, each new rover has captured “strange objects”. Curiosity, launched by Nasa, photographed a rock in 2014 that looked like a thigh bone, some observers thought.
Another image in 2015 showed a formation that many believed resembled a floating spoon. And in 2022, Curiosity sent back a picture of a narrow crack in a cliff wall that was described as a “doorway”, even though scientists explained it was the result of natural fracturing.
Opportunity, a rover that explored Mars for 15 years, came across tiny spherical pebbles in 2004 that scientists called “blueberries”.
Why our brains see helmets and faces
Dr Sneha John, clinical psychologist at Aspris Wellbeing Centre Dubai, said our brains try to find patterns in objects because of a phenomenon called pareidolia. This is when humans perceive a familiar pattern or meaning in inanimate objects.
“The human brain is wired to detect patterns for survival, social connection and familiarity,” Dr John said. “This false positive happens because the human brain is wired to quickly identify faces, which is a useful survival trait for detecting threats.
“When we see faces or cities in the rocks of Mars or the craters of the Moon, we are really seeing ourselves and our need to find patterns and our deep longing for connection.
“These illusions are less about alien civilisations and more about the very human desire for meaning, companionship and hope in an otherwise indifferent universe.”
Public fascination
Dr Atri said these viral moments can help in attracting interest in planetary science, but they can also drive the spread of misinformation.
“When rocks become ‘alien helmets’, it spreads confusion,” he said. "The challenge is turning that curiosity into genuine scientific understanding rather than sensationalism. The public wants mystery and we should give them actual science instead of letting clickbait win.”
Nasa has tried to strike that balance by acknowledging the fun side of these images while releasing explanations. Its website features “Image of the Day” that encourage public engagement, but their scientists also debunk conspiracy theories.
