If you didn’t know the context, pictures of the Sahara Desert from the edge of space could easily be mistaken for the surface of Mars instead.
The western edge of the African desert is caked in red-tinged sand, which turn into seas of dunes that move with the wind, void of any greenery or human-built infrastructure.
An astronaut aboard the International Space Station recently took a photograph while orbiting over southeastern Morocco, near the border with Algeria.
The breathtaking image, shared by NASA Earth Observatory, shows the area of Erg Chebbi, a sand sea that covers an area of 11.2 miles by 5.6 miles in North Africa.
The sand sheet is home to numerous features found in very few places on Earth, such as star dunes, also known as pyramid dunes. These mounds are formed by wind-blowing masses of sand in different directions, creating a dune with a central peak and several ridges that radiate outwards like a star or pyramid shape.
This type of dune can form some of the tallest on Earth, reaching up to an incredible 300 metres.
Such dunes can be found elsewhere in the solar system, such as Mars, Saturn’s moon, and Titan. Closer to home, they can also be seen in the Arabian Peninsula, China and North America.
The Badain Jaran Desert in China is home to some of the tallest on earth. In fact, the world’s tallest stabilised sand mega-dune, which peaks at around 460 metres, is found here, which is taller than the Empire State Building. It has been added to the World Heritage List by UNESCO.
Earlier this year, the age of the dune called Lala Lallia in Morocco was calculated for the first time, revealed to have been formed 13,000 years ago. It is 100 metres high and 700 metres wide with radiating arms.
After its initial formation, it stopped growing for 8,000 years and then quickly expanded in the past several thousand years, the BBC reported.
Prof Geogg Duller from the University of Aberystwyth, who published the research with Prof Charles Bristow at Birkbeck University, added: “These findings will probably surprise a lot of people as we can see how quickly this enormous dune formed, and that it is moving across the desert at about 50cm a year”.
“Despite their large size and prominence within sand seas, or possibly because of their large size, star dunes are the least studied dune type,” said a 2024 paper in the Nature Journal.
However, unlike on the inhospitable landscape Mars, Erg Chebbi may look martian but life has found a way. Towards the bottom of the dune complex, there is a large aquifer that supports palm groves and the town of Marzouga.
Meanwhile, at the top of the dunes, one can also see a small cluster of camps. Traditionally, these would have been inhabited by the Indigenous Amazigh (Berber) peoples, who lived nomadically in North Africa for many millennia.
Today, however, they are mainly frequented by tourists keen to tick the Sahara Desert off their bucket lists, including by dune surfing or via jeep tours.
