An international team of planetary scientists observed, “for the first time, the movement of giant waves of sand, called megaripples ('megaondulations'), on the planet Mars”, announced today the University of Coimbra (UC).
The team of experts who made the discovery, which results from “about a decade of observations” (between 2007 and 2016), is part of David Vaz, of the Center for Research on Earth and Space at the University of Coimbra (CITEUC), underlines UC, in a note sent today to the Lusa agency.
The discovery is particularly relevant, since, “until now, it was thought that these structures – because they are made up of particles of thicker sand – would not be active (the wind currently would not be able to move these particles)”, says the University.
“Since there was no evidence that they were moving, they were believed to be‘ relics ’of the strongest wind activity that would have existed in the past on Mars. However, our observations are quite conclusive and contradict this view, that is, the megaripples on Mars are definitely active ”, says David Vaz.
To reach this conclusion – “megaondulations” move across the red planet, albeit slowly (about 10 centimeters per year) -, the team led by Simone Silvestro, from INAF-Osservatorio Astronomico di Capodimonte (Italy), analyzed more than a thousand of these sedimentary structures.
To this end, the UC said, the researchers used “high-resolution images acquired by NASA's Mars Reconnaissance Orbiter, in two regions of Mars: McLaughlin crater and Nili Fossae”.
The participation of the CITEUC researcher in this work focused on the “processing of the surface images obtained by the probe and the application of various techniques, developed previously, that allow to measure with great precision the sediment flows (transport speed and quantity of sediments transported by wind) on the surface of Mars ”.
In the study it was “particularly important to measure the speed and the way in which 'megaripples', a specific type of ripples that are formed by the transport of sediments due to the action of the wind, moved during a time interval of almost 10 terrestrial years”, stresses, cited by UC, David Vaz.
David Vaz also contributed with a set of measurements of migration speed and sedimentary flows to dunes in other regions of Mars, “which served to frame and explain the observations made in the two areas in which the study focuses”, having also participated in the work that took place in the Moroccan desert in 2017 and in 2019, where “terrestrial megaripples” were studied.