An astronaut captured an eerie photo of a huge skull that appears to be staring back toward space from the Earth’s surface.
The chilling photo was captured by an unnamed astronaut on February 12 aboard the International Space Station (ISS), as the spacecraft passed above the Tibesti Massif — a mountain range that stretches across the center of the Sahara Desert through Chad and Libya.
However, NASA shared the astronaut’s spooky photo of the distinctive skull-shaped feature on October 31 to celebrate Halloween.
The photograph was captured by the unnamed astronaut with a Nikon D5 digital camera using a focal length of 500mm.
While the photo may have to show a creepy giant skull glowering back at the astronaut, it is actually a strangely shaped volcanic crater lurking in the Sahara desert.
The skull-shaped feature is located on the floor of Trou au Natron, also known as Doon Orei — a 3,300-foot-wide (1,000 meters) volcanic caldera, or crater, that was left behind by a massive volcanic eruption hundreds of thousands of years ago.
The geological indentation is located just to the south of Tarso Toussidé, an even larger volcanic feature that is home to a potentially active stratovolcano.
The edge of the skull’s “face” is partly formed by shadows cast by the rim of a caldera—a type of volcanic crater formed after an explosive eruption or the collapse of the surface into a partially emptied magma chamber.
The “eyes” and “nose” of the skull’s face are cinder cones — which are steep conical hills built around volcanic vents that tower above the rest of the caldera floor
Meanwhile, the white shade of the skull’s mouth, nose, and left cheek is a mineral crust known as natron, a naturally occurring salty mixture of sodium carbonate decahydrate, sodium bicarbonate, sodium chloride, and sodium sulfate. The darker area to the left of the face is the shadow cast by the tall rim of the crater, which helps give the skull its distinctive shape.
It is unknown exactly how or when Trou au Natron was formed, but experts believe it was a thriving glacial lake until around 14,000 years ago.
Image credits: All photos by ISS/NASA.
Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
