Ghost dunes on Mars surface
Researchers have discovered hundreds of crescent-shaped pits on Mars. They are the imprints of long-vanished ancient sand dunes that once raised high above the mars surface.
According to research, the pits formed around two billion years back. Back then Mars would have appeared to be extremely unique to how it shows up today, with streaming water on its surface and active volcanoes.
It is suspected that lava or sediments in water incompletely covered the dunes before solidifying into a structure that preserved their contours. After some time, winds overwhelmed sand away from the tops and the inside leaving an empty shell known as a “ghost dune”.
While, the ghost dunes provide potential insights to Mars past climate and even contain confirmation of ancient life. Ghost dunes initially revealed on Earth in 2016 on the Snake River Plain in eastern Idaho.
Identifies hundreds of ghost dunes
Scientists from the University of Washington identified around 300 of the ghost dunes in the Hellas Basin. Meanwhile, another 500 are located in Noctis Labyrinthus, a maze-like system of steep-walled valleys on the equator.
To discover them, scientists searched for clusters of crescent-shaped pits which all aligned in the same way. The pits seem very similar in shape to ‘barchan dunes’, the most common type of dune on both Earth and Mars. These formed by winds blowing mainly from a single direction.
With the latest space science news, researchers evaluate how big the “ghost dunes” contrasting them with existing dunes on Mars. They found that those in the Hellas Basin measured around 250 feet tall on average, while those in Noctis Labyrinthus came to around 130 feet.
While, researchers propose winds did not completely clear out the shell of the vanished dunes, leaving sheltered pockets with ancient sand in them that could possibly contain hints of ancient microbes.