Sand ripples are fascinating. They’re symmetrical, yet wind — which causes them — may be very much not. Moreover, they might be found on Mars and on Earth. They’d be much more fascinating if the identical effect found on Mars may very well be found here on Earth as well. What if one unified theory could explain their formation on two different planets of our solar system?
That’s what Ben-Gurion University of the Negev physicist Prof. Hezi Yizhaq and Prof. Itzhak Katra and their colleagues from Denmark, Germany, Italy, China, and the US contend in a canopy article published in Nature Geoscience.
Sand ripples photographed on Mars by NASA’s Curiosity rover in 2015 showed two distinct patterns — large ripples (meter scale) and a shorter “impact” ripples pattern (decimeter scale). The prevailing theory proposed since then argues that the smaller scale ripples are produced by the impact mechanism of the particles transported by the wind like normal ripples on Earth and the larger ripples form on account of hydrodynamic instability like subaqueous ripples. Moreover, it was believed that the physical conditions that produced them on Mars couldn’t produce them on Earth.
Nevertheless, Prof. Yizhaq and Prof. Katra have proven experimentally using Ben-Gurion University’s wind tunnel and Aarhus University’s Mars tunnel that such a phenomenon could exist on Earth — we just have not noticed it yet because we didn’t know we ought to be in search of it.
Imitating Martian sand was challenging since it’s finer than sand here on Earth, explains Prof. Yizhaq, however the breakthrough occurred after they decided to try tiny glass balls to represent effective grains of sand.
Moreover, the international research team has proposed a unified theoretical framework that might explain sand ripples on Mars and on Earth. At its most simple level, sand ripples on Mars brought on by wind appear to be sand ripples on Earth brought on by water.
“There’s way more research, each fieldwork and experimentally, needed to prove our theory, however it is amazing to propose something so radically latest in a field I actually have been studying for over 20 years. It’s exciting to exit and check out to search out on Earth what can clearly be seen on Mars,” says Prof. Yizhaq.
Prof. Yizhaq is a member of the Department of Solar Energy and Environmental Physics. Prof. Itzhak Katra is a member of the Department of Environmental, Geoinformatics and Urban Planning Sciences.
The research was supported by the Israel Science Foundation (Grant no. 1270/20), the German-Israel Foundation for Scientific Research and Development (GIF) (Grant no. 155-301.10/2018), the National Natural Science Foundation of China, Texas A&M Engineering Experiment Station, Europlanet grant no. 871149, and the Horizon 2020 Research and Innovation Program.
