An astronaut aboard the International Space Station photographed a 100-square-kilometer rock formation in southern Madagascar that resembles the lunar surface. The geological feature, known as Sariaky, consists of anorthosite—a rock type found in the bright highlands of the moon—and rests amidst rust-colored arid terrain.
How the Sariaky Formation Compares to Lunar Highland Rocks
The Sariaky mass is composed of anorthosite, a rock type that forms when molten rock cools and solidifies beneath the surface, allowing large crystals to grow. Scientists believe the anorthosite on the moon formed more than 4 billion years ago when the moon was in its early stages and covered by a vast ocean of molten rock. As those rocks cooled, some minerals gathered near the surface and contributed to the formation of the moon’s outer crust. Similar rocks exist in eastern Canada, Scandinavia, southern India, and the Beartooth Mountains of Montana. Researchers study these terrestrial analogues because the samples returned by Apollo missions to Earth are limited.
The 600-Million-Year Tectonic History of Southern Madagascar
The landscape surrounding Sariaky holds a record of deep-earth pressures that bent, stretched, and deformed rocks over millions of years. Scientists link these transformations to the assembly of an ancient supercontinent known as Gondwana, which included parts of Africa, India, Madagascar, Australia, and the current Antarctic continent. Intense heat and pressure from continental movement reshaped the rocks’ form and structure. Some researchers believe that another rock mass located approximately 60 kilometers north of Sariaky was connected to it in the past, before geological forces caused the two masses to separate.
Details of the International Space Station Photograph
An astronaut aboard the International Space Station captured the formation on August 28, 2026, using a Nikon Z9 camera equipped with a long-range lens. The resulting image, cataloged under the identifier ISS075-E-85249, was provided by the Earth Observations team at the International Space Station in cooperation with the Earth Science and Remote Sensing Unit at the Johnson Space Center, and was adjusted to improve the clarity of details and the contrast between the rocks and the surrounding terrain.
