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Astronomers found out ghost dunes on Mars, they have acquired images of ghost dunes which is tall crescent-shaped sand dunes once existed on this red planet.
As we know, Mars is a desert planet, and it is more like Earth than any other planet, but it is colder there than on Earth. Also just like Earth, the Martian deserts have massive dunes. Astronomers informed the finding in GeoSpace on July 10, 2018. The new research paper was just published in the Journal of Geophysical Research.
They say that these ghost dunes are not active dunes currently. It is more likely that the dunes are the remains of previous ancient dunes that left pit-like depressions in the ground after they eroded away. A lot of these crescent-shaped pits have been found, each about the size of the U.S. Capitol building.
A planetary geomorphologist at the University of Washington in Seattle and an author of the new study, Mackenzie Day, clarified:
“Any one of these pits is not enough to tell you that it’s a dune, or from an ancient dune field, but when you put them all together, they have so many commonalities with dunes on Mars and on Earth that you have to employ some kind of fantastic explanation to explain them as anything other than dunes”.
The important question in which way the ghost dunes may emerged?
On Earth, these phenomena may be formed by partially buried by lava or water-borne sediments. For these Martian ghost dunes, when the lava or sediments hardened, they preserved the contours of the dunes. These dunes’ existence on Mars provide more hints as to what conditions were like billions of years ago, in particular, winds. According to Day “One of the cool things about the ghost dunes is that they tell us, for sure, that the wind on Mars was different in the ancient past, when they formed. The fact that the wind was different [when the ghost dunes formed] tells us that the environmental conditions on Mars aren’t static over long time scales, they have changed over the past couple billion years, something we need to know to interpret the geology on Mars”.