April 30, 2018

Wild & dark lacy dunes on twisty bright layers

Some windblown dunes on Mars are just beyond words. Take these beasts in this 0.95×0.95 km (0.59×0.59 mi) scene: These are a peculiar type of bedform called a transverse aeolian ridge, or TAR for short, with a spacing of about […]
April 23, 2018

Reusing old canvases

The wind on Mars is an artist, or at least it tries really hard to be one. It flutters up and down mountains, winding along valleys, dragging its wings in the sand and building up really amazing structures that could […]
April 16, 2018

Flow. Lots of flow.

Over the years, many things have flowed across the surface of Mars: lava, ice, water, and wind. Two things have flowed in this image (the view is 0.75×0.6 km or 0.47×0.37 mi): Image credit: HiRISE ESP_026541_1840, NASA/JPL/Univ. of Arizona If […]
March 12, 2018

Wind on Mars and the Huygens-Fresnel Principle

How about some basic physics? It’ll be easy, I promise. Just look at the pretty picture below (click on it to see it better): (HiRISE ESP_045586_1585, NASA/JPL/Univ. of Arizona) The big crater is ~400 m (1/4 mile) across. Wind blows […]
February 12, 2018

Where dune fields begin

This is the upwind edge of a dune field (825×625 m, 0.51×0.39 mi). Winds blow down a cliff (offscreen) from the lower right, blowing sand toward the upper left. Elongated dunes have formed parallel to the resultant wind direction, only […]
January 22, 2018

Arnus Vallis, Mars

A Piece of Mars: This is a section of Arnus Vallis (scene is 1.25×1 km, 0.78×0.62 mi). It’s a >300 km long valley that was carved out, not by water, but by lava, long ago. Since then the wind has […]
January 2, 2018

Fuzzy dunes

A Piece of Mars: The dunes (or maybe they’re ripples) in this valley appear to be fuzzy (the view is 625×775 m, 0.39×0.48 mi). They’re not really fuzzy, but it’s not actually clear what’s going on. They seem to have […]
December 4, 2017

Ripples of rock

A Piece of Mars: To the upper right of this 0.85×0.6 km (0.53×0.37 mi) scene is a flat-lying plain strewn with large ripples. To the lower left is a rugged hill with gray rock laced with white veins (this might […]
November 8, 2017

Island in the stream

A Piece of Mars: In the floor of what might have been an old fluvial channel there are a bunch of really neat dunes (or maybe ripples, they’re TARs and we don’t know yet what they are). One spire pokes […]