Fashionable stripes of Mars
A piece of Mars: Is it the latest in patterns for ties, or is it Mars? (Can it be both?) These are some unusually regular dunes on Mars, separated by a bouldered surface. The dunes have interesting pale bands common in this region on Mars, as well as an unending supply of long, parallel ripples. (HiRISE ESP_025108_1370)
At the edge
A piece of Mars: Old, subdued dunes (in blue) near the south pole on Mars. This shows the edge of a dune field, with white rock-strewn surface beyond the sand. Criss-crossing the sand are the tracks that dust devils have left behind. I wonder if these whirlwinds are the main reason why the dunes are slowly eroding to a flat surface. (HiRISE PSP_005980_1085)
When dunes die
A piece of Mars: This is what dunes look like when they die. At least on Mars. On Earth they typically get buried or eroded away. On Mars geology works slowly enough that the steep slopes of dunes are gradually reworked and pitted, and covered in fine layers of bright dust. (HiRISE PSP_005980_1085)
Staircases
A piece of Mars: Sedimentary layers on Mars are revealed by sandblasting. These are giant staircases dropping down towards the upper right, looking like some old eroded temple or city. Some bluish sand remains as a reminder of what scoured them clean. Sorry, Ozymandius, even Mars has you beat. (HiRISE PSP_002733_1880)
May 20th Solar Eclipse
On May 20th, 2012, our area of Northern California was treated to a partial solar eclipse. After nabbing some eclipse viewing glasses from work, courtesy of NASA, I was excited to share this experience with my kids – they had seen lunar eclipses before but never a solar eclipse.
Ripples in a crater
A piece of Mars: Many small craters on Mars are filled, at least in part, by small dunes or ripples. It’s one of the distinguishing features of Mars — a surface marked by geology both old (craters) and young (dunes). This particular crater isn’t so old — boulders surrounding it were made from rocks flung from the impact when it formed, and they are usually one of the first things to erode away as a crater ages. (HiRISE ESP_026726_1790)
Dust and oddities
A piece of Mars: In the dustier regions of Mars, there are many small dark streaks on steep slopes that we don’t understand well. Because we don’t know much about them we call them “slope streaks”, which is not the most imaginative name. They are actively forming on Mars today, though, and seem to be triggered by a disturbance like a nearby earth(mars)quake or a strong wind. Over the next several decades they slowly fade away. (HiRISE ESP_014394_2045)
Wind and hills
A piece of Mars: Blueish and yellowish ripples wind their way around a bright hill. The yellowish ones are probably not moving anymore, but the blueish ones are likely still active from time to time. (HiRISE ESP_020889_1320)
Swirls like ribbon ice cream
A piece of Mars: When the wind erodes layered rocks, it can create a dramatic swirly pattern like this. It looks like ribbon ice cream to me. Mmm, rocks. (HiRISE ESP_011582_1730)
One perfect barchan on Mars
A piece of Mars: In nature most dunes pile on one another or strongly influence each other. But occasionally, like a perfect flower or crystal, you find a perfectly shaped dune. Here is a crescentic dune, called a “barchan”, formed by winds moving from right to left. (HiRISE PSP_007676_1385)