The stunning landscape of the Red Planet has troubled scientists for a while. How did the dunes and gullies of Mars continue to form without a dense Earthlike atmosphere? Now, researchers from the Open University in the UK think they have found what’s happening.
The team suggests that the landscape is partly being shaped by levitating sand. Mars is a cold dry desert but in certain areas during certain times of the year, it is warm enough for a little bit of water to flow on its surface. This water is believed to be very briny and is the cause of the famous slope lineae. This surface liquid begins to boil due to the extremely low pressure (0.7 percent of our own) and a large amount of sand begins to glide, levitating on the boiling water.
The research, published in Nature Communications, was carried out in the Open Univerity's Mars simulation chamber. The instrument is used to replicate the likely pressure and temperature conditions of the Red Planet and in this experiment showed that a large amount of sand can be moved with just a little bit of water. This could explain the movement of dunes on Mars.
“Whilst planetary scientists already know that the surface of Mars has features such as dune flows, gullies, and recurring slope lineae that occur as a result of sediment transportation down a slope, the debate continues about what is forming these recent and present-day active features,” lead author Jan Raack said in a statement. “Our research has discovered that the levitation effect caused by boiling water under low pressure enables the rapid transport of sand and sediment across the surface. This is a new geological phenomenon that doesn’t happen on Earth, and could be vital to understanding similar processes on other planetary surfaces.”
The simulations show that levitation makes sediment transport nine times greater and taking into account the lower Martian gravity, it could persist for about 48 times longer than the experiments have indicated.
“The sources of this liquid water will require more observational studies; however, the research shows that the effects of relatively small amounts of water on Mars in forming features on the surface may have been widely underestimated," added Raack. "We need to carry out more research into how water levitates on Mars, and missions such as the ESA ExoMars 2020 Rover will provide vital insights to help us better understand these processes on our closest planetary neighbour.”
The Martian landscape has been in the news recently as a sand producing hotspot was located by NASA’s Mars Reconnaissance Orbiter.