Study finds dunes and ridges can form without much wind
Once Martian sand grains hop, they don’t stop.
That’s the conclusion of a new study that finds sand can move on Mars without much windy encouragement.
Mars’ sandy surface has clearly been shaped by wind. Its characteristic dunes and ripples are the kind formed by sand particles taking short wind-borne hops, a process called saltation.
But atmospheric simulations and landers’ direct measurements of wind speed have found that the Martian wind hardly ever blows hard enough to kick sand grains off the ground in the first place.
The new paper, to appear in an upcoming Physical Review Letters, suggests a solution to this paradox: a kind of billi