lfenton

June 18, 2014

Swirly rocks

A piece of Mars: Never mind the 4 m (13 ft) boulders that have fallen downslope, or the rippled sandy surfaces here. Look at those bright swirls in the ground. Those are the former interiors of sand dunes, which were […]
June 13, 2014

Whither the wind

A piece of Mars: Which way did the wind blow here? You can tell by looking at the dune and its ripples. The slip face (the avalanching slope of the dune) faces downwind, so the strongest wind here mainly blows […]
June 2, 2014

The always-changing landscape

A piece of Mars: Over time, windblown sand can wear down a surface. This isn’t so common on Earth, where water, ice, and life are more likely to change the landscape, but it’s typical of many places on Mars. Here, […]
May 26, 2014

Flow

A piece of Mars: This is a bit of the flank of Arsia Mons, one of Mars’ great volcanoes. The big changes in topography are ancient relics of erosion by lava and great tectonic pulling. What I like is that […]
May 19, 2014

Debunking Hoagland’s “Glass Worms” with HiRISE

A piece of Mars: Several years ago, a guy named Richard Hoagland claimed that some parallel linear features on Mars looked like the ridges of a transparent earthworm, calling these things “glass worms”. Phil Plait debunked it nicely, but Hoagland […]
May 12, 2014

How we know wind blows down Olympus Mons’ flanks

A piece of Mars: It’s similar to my last post, but I love these wind tails. This is a tiny bit of the eastern slope of the gigantic volcano, Olympus Mons. The dusty surface has been covered by boulders (the […]
May 5, 2014

The wind giveth and the wind taketh away

A piece of Mars: In the center of this image is a 270 m crater (885 ft) that was nearly buried, along with the surrounding terrain, by dust. Since then, wind from the upper left has scoured the dust deposit, […]
April 28, 2014

Big ripples near Opportunity

A piece of Mars: This shows the location of the rover Opportunity as of late March, 2014. It’s been trolling around the rim of Endeavour crater. Just inside the crater, there are some large ripples (the biggest is ~10 m […]
April 21, 2014

Uniquely martian

A piece of Mars: Now here’s something that, as far as I know, can safely be labeled as “uniquely martian”. These dunes (or maybe they’re ripples) are ~25 m wide, and have formed from winds blowing from the upper left. […]