HiRISE images

May 3, 2022 I don't typically have much time for these posts anymore. The pandemic seems to have changed everything. But sometimes I need to remind myself why I do this for a living. Going to look through Mars' gorgeous scenery is one way I can ground myself (pun not intended). My hope is that by writing these blog posts, I can perhaps share some of that with others. So let's have another awesome look at Mars, hmm? HiRISE image ESP_069655_1510. Most of the topography is either old, eroded windblown dune-like features, or modern ones that are quite similar.... read more ❯

March 29, 2021 Mars is such a fun place. We're finding out that it's got oodles of geologic history. It's got layers deposited by wind and water and lava, altered in place (sometimes many times), then eroded again by wind and water and lava. It's never boring. My favorite, of course, is the wind. I really like modern dunes that are now crawling across the surface and the wind blows their sand along. But I also like old ones that preserve information about the wind patterns from a long time ago. This is ESP_068039_1780, a really spectacular HiRISE image that shows a lot... read more ❯

16 December, 2020 This year I haven't had time to write many blog posts. That's a shame, because they're what often reminds me of how amazing Mars is (and by extension, the Earth, and all the other worlds out there). The pandemic has left its mark on all of us. I'm fortunate enough to be funded (but that may end - I don't foresee spending on NASA to be plentiful in the coming hard years). The upside is that for now I can work. The downside is that I'm behind in all of my projects, and also trying to get my... read more ❯

Sept. 2, 2020 Dunes don't usually form on hills. They're made of sand, which is moved by wind (and water and ice) and tends to linger where it gets stuck. You probably know this intimately if you've spent time at a sandy beach. It's true not only on the scale of the threads of a beach towel and in jeans pockets, but also on a larger scale. Dune fields are made of windblown sand that piles up in valleys, or whatever topographic low it's being blown past. The biggest sand sea on Mars, for example, is found at the bottom of... read more ❯

July 17, 2020 A couple months ago I wrote a blog post about defrosting dunes in Jeans crater, some wild southern polar dunes on Mars. Well it's been that time of year on Mars, so I'm going to show some more. These aren't in Jeans crater, but in another unnamed crater at about 70°S (that's pretty far south). First let's have a look at the crater, for some context: CTX images of the crater (Image credit: NASA/JPL/MSSS, made in JMARS) MOLA elevation + shaded relief of the crater (Image credit: NASA, made in JMARS) On the left above are images of the crater and... read more ❯

June 15, 2020 Utopia Planitia is an ancient plain in the northern lowlands of Mars, thought to be made of volcanic rocks that were buried, more than 3 billion years ago, by sediments carried by water coming down from the southern highlands (this is the wonderfully vast late Hesperian lowland unit ("lHl") of Tanaka et al., 2014). After the sediments piled up, most of the surface hasn't had a lot happen to it, although in some places there are signs of glacial activity and other modifications by ice. Here, though, what is interesting to me is the scattered windblown bedforms, like those... read more ❯

June 8, 2020 No long descriptions or explanations today, just a pretty picture of a lee dune (the dark rippled finger extending down the left side of this image): The rounded gray hills at the top are part of the little central peak of a~25 km diameter crater.  Why is the dune there? Well first let's see where it is to begin with. Here's some context: [caption id=""... read more ❯

May 26, 2020 There are sand dunes near both the north and south poles of Mars. The ones I'm showing today are on the floor of Jeans crater, which is down at 69.5°S (for reference, on Earth, some bits of Antarctica reach to this latitude). Jeans crater is 74 km (46 mi) across, and like many of the larger craters in the southern highlands of Mars, it's got a dune field in it. This far south, the dune field spends a lot of its time covered in seasonal CO2 frost. It's just past Mars' antarctic circle, which means it spends part of... read more ❯

March 25, 2020 It's been an interesting few weeks. Like many folks, I'm trying to work from home while keeping my kids busy. I'm fortunate to have a job that allows me to work at home, so I can continue to make progress away from the office. It does mean that my work at the Mars Wind Tunnel at NASA Ames is on hold, as is my planned dust devil fieldwork. That's a bummer. But I've got plenty to work on in the meantime. I thought today I'd show off one of the many craters in Arabia Terra on Mars that has... read more ❯

Feb. 17, 2020 I've been busy but I wanted to squeeze in a quick pretty picture of some Mars dunes. These: These dark hills of windblown sand are on the small side for Mars. The smallest is ~88 m (288 ft) across (for reference the smaller dunes found on Earth are usually 1/4 this size). What's cool about them is the variation in their slip faces: that steep slope that is just crying out for someone to slide down it (or roll down... read more ❯