Martian Dune Mystery Solved by Bouncing Sand Grains | Wired Scie. 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 billiard-ball effect in which one sand particle knocks the next one into motion. Kok modified a numerical model, previously applied to geological processes on Earth, to include Martian gravity and atmospheric conditions.
“That’s hard to study in a wind tunnel,” notes planetary scientist Robert Sullivan of Cornell University. See Also: Welcome to mactonnies.com! - (Build 20090824085414) I'm a Kansas City, Missouri-based author and essayist. I blog daily at Posthuman Blues and tweet religiously. My latest book is After the Martian Apocalypse (Paraview Pocket Books, 2004), a speculative and generally well-received examination of extraterrestrial intelligence on the Red Planet.
I'm presently at work on a new non-fiction book titled The Cryptoterrestrials: Indigenous Humanoids and the Aliens Among Us, excerpts of which I've posted on my blog. If you're in the mood for a multiplex Fortean anthology, my essay "The Ancients Are Watching" is included in 2008's Darklore Vol. II. (My first book, Illumined Black, is a collection of naively "Blade Runner"-ish science fiction short-stories. Mars Anomaly Research Home Page. Cydonian Imperative - (Build 20090824085414) 632b.jpg (JPEG Image, 260x260 pixels) - (Build 20100401064631)