Planetary scientists: Radar anomalies at the south pole of Mars are caused by dust

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American planetary scientists have discovered that radar anomalies at the south pole of Mars are caused by dust, and for such anomalies to appear in the radar signal, a thin layer consisting of dust is sufficient.

American planetary scientists have come to the conclusions that radar anomalies discovered in 2018 at the south pole of Mars are not caused by subglacial lakes of liquid water, but by thin layers of water ice containing a large number of dust particles. 

Daniel Lalic, a researcher at Cornell University in America, explained: “For the first time, we put forward a hypothesis that explains all the known radar anomalies found in the depths of the ice caps of Mars, and our calculations showed that the unusual nature of the reflection of radar radio waves can be explained by the fact that those waves are scattered by a thin layer of dust.” ".

Lalic and his colleagues pointed out that Italian astronomers who worked with the European Mars Express probe were able to detect traces of the presence of three subglacial lakes located at a depth of 1.5 kilometers from the surface of the planet’s southern ice sheet in radar images of Mars’ South Pole.

Astronomers had previously discovered many similar anomalies, which forced them to actively discuss the nature of these discoveries. Many planetary scientists immediately doubted these results and assumed that the Mars Express probe's instruments had detected some kind of radar "mirage" or deposits of clay or other rocks, and not subglacial lakes. These ideas have sparked much controversy about radar anomalies, the nature of which remains a matter of debate among planetary scientists.

Lalic and his colleagues put forward a new theory that explains the existence of these anomalies and all their unusual properties by the presence of a thin layer or several layers of water ice containing large quantities of dust particles deep in the ice at the south pole of Mars. It scatters radio waves from the MARSIS radar on board the Mars Express probe so that anomalies similar to the effects of subglacial lakes appear in the radio signal reflected from the ice.

As indicated by calculations conducted by scientists, for such anomalies to appear in the radar signal, it is sufficient to have a very thin layer of ice several meters thick, which consists of approximately 10% of dust particles and is adjacent to the layers of ice where the percentage of dust is much lower.

Planetary scientists have concluded that similar variations in the structure and composition of ice may exist within the southern polar cap and in other ice deposits on Mars, which explains the widespread presence of radar anomalies at depth.