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Have you ever heard of the blue dunes on Mars Inquisitr but what are the "ghost dunes"?
Well, as you probably know now, the surface of the red planet is punctuated by sand dunes. Some of them are newer, more modern, as are the dunes of barchan (crescent shaped) found in the craters of Oyama and Herschel; others are ancient and date back billions of years, when Mars still had flowing water and active volcanoes.
In the ancient past of the planet, some of these dunes were covered with lava, which hardened into a kind of a cast that enclosed ancient material in the sand dunes. Later, when the winds swept the top of the dunes, they carried off the upper layers of sand, leaving behind the empty casts that are now preserved as pits in the Martian surface.
Because they are hollow remains of ancient sand dunes, these empty pits or shells have been dubbed "ghost dunes", and the researchers have recently located about 800 of them, found grouped in two distinct regions on the red planet, reports Science Magazine . was made by planetary geomorphologist Mackenzie Day and astrobiologist David Catling, both affiliated with the University of Washington at Seattle and the Institute of Astrobiology at NASA California.
Scientists discover ghost dunes on #March https: / /t.co/OZBCQw3x8R
– Phys.org (@physorg_com) July 11, 2018
C & # 39 is the first time that ghost dune pits have been discovered on Mars, reveals a new study, published by Day and Catling in the Journal of Geophysical Research .
These new geological features were discovered by satellite images and are grouped into two dune fields erected in very distinct areas on Mars. About 480 of these pits were discovered at Noctis Labyrinthus, a region similar to a labyrinth of steep canyons and valleys, while another 300 dune ghosts were detected in the Planitia Hellas, an impact crater of more than 2 500 km. By comparing ghost dunes with modern sand dunes in the Oyama and Herschel craters, the two researchers were able to calculate their age, size, and size.
According to GeoSpace the American Geophysical Union's blog, the newly discovered ghost dunes on Mars appear to have been formed about 2 billion years ago at the end of the year. Hesperian, a tumultuous and transient period The history of the planet is characterized by extensive volcanic activity and a catastrophic flood.
Inspired by this discovery, Day noted that all common features of these sand pits indicate an ancient dune system preserved by partial burial.
"No matter which of these pits is not enough to tell you that it's a dune, or an old dune field, but when you put them all together, they have so much in common with the dunes on Mars and on Earth. "
The two researchers believe that the ghost dunes of Noctis Labyrinthus were about 40 meters (130 feet) high when they were buried for the first time under the lava flows, while those in the Hellas Basin were almost twice as high: at a height of 75 meters (246 feet), these sand dunes were almost the size of the US Capitol building, note Atlas Obscura .
Another peculiarity of the ghost dunes is that they are all crescent-shaped croissants and oriented in the same direction, molded by winds from the north and gently pushing the sand towards the south – something that we do not see on March today.
"One of the cool things about the ghost The dunes, that is, they tell us, for sure, that the wind on Mars was different in the past, when they formed," says Day .
A look at the history of Mars
that the environmental conditions on Mars do not remain static for long periods and have in fact changed a lot over the past two billion years. 39 years – a very important revelation for the study of Martian geology.
The reason why this is relevant is because ghost dune pits can actually be lined with water. "Aeolian strata can be kept in pits at a once hot or water-rich interface, which makes pits Interest in astrobiology, "write the authors. their newspaper.
Science Magazine's latest news: 'Ghost dunes & # 39; spotted on Mars https://t.co/WWtVtqHfZK
– ScienceSeeker Feed (@SciSeekFeed) 11 July 2018
"We know that dunes on Earth can support life," said Day, pointing out that the sand dunes on Mars are very similar to those found at home.
In fact, ghost dunes also occur on Earth and were discovered the first time in 2016. Discoveries on the plain of the Snake River in East of Idaho, these ghost dunes go back to the end of the Pleistocene, reports Atlas Obscura .
Microbial life at the bottom of these ancient sand dunes. And, in the case of the red planet, the dunes would have sheltered the intense surface radiation, increasing the chances that they could still show signs of extraterrestrial life, explains Day.
"There is probably nothing alive there now. But if there is anything on Mars, it's a better place than the average to watch. "
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