‘Ghost dunes’ can be key to quest for life on Red Planet

Mindy Sparks
July 13, 2018

Lava or sediments washed into the area with water and partially buried these dunes as it streamed around them. After wind blew the exposed sand away, the mold inside remained and showed where the full dune used to be.

Studying these ghost dunes can provide potential clues to Mars's past climate, and may even contain evidence of ancient life, the researchers said.

They were first uncovered in 2016, but now a study has finally reported on the extraordinary phenomenon. Once there, the landers were created to analyze the planet's soil and, ideally, discover organic remains that pointed to the presence of life long ago. The pits mark the location where huge sand dunes, hundreds of feet high, stood billions of years ago.

Meanwhile, the other 500 or so are located in Noctis Labyrinthus-a maze-like system of steep-walled valleys on the equator.

Another theory from McKay's colleague, Melissa Guzman of the LATMOS research center, is that the chlorobenzene hitched a ride to Mars aboard the Viking landers.

The discovery thrilled experts who believe they could possibly hold evidence of ancient life.

The pits appear very similar in shape to "barchan dunes", the most common type of dune on both Earth and Mars.

"They are all going the same way, which you would expect for dunes because they are all migrating and forming in the same wind regime", Day said.

The two researchers estimate that the ghost dunes at Noctis Labyrinthus were about 40 meters (130 feet) high when they were first buried under the lava streams, while the ones at the Hellas basin stood nearly twice as tall.

"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 timescales, they have changed over the past couple billion years, something we need to know to interpret the geology on Mars", Day said.

By comparing the ghost dunes with the modern sand dunes in the Oyama and Herschel craters, the two researchers were able to calculate their age, size, and shape.

If Mars has ancient organic matter, then it's a proof that it could have supported life and it might have some sort of life forms today.

These "ghost dunes" remain preserved due to their composition.

"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", said Day.

They found them by examining images of Mars' surface for clusters of crescent-shaped pits, "aligned like croissants on a baker's tray", as Lester puts it. If you are inside a dune, or at the bottom of a dune, and you are microbial life, the dune is protecting you from a lot of that radiation.

Ms Day added: "There is probably nothing living there now".

Scientists still can't say with utter certainty whether life ever existed on Mars.

Other reports by Iphone Fresh

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