A piece of Mars: This 480×270 m (0.3×0.17 mi) area is a steep slope that plunges down to the upper left. A pile of dark sand, covered by brighter tan dust, clings to the hillside. Usually the martian wind blows sand into ripples, and you can see where it’s tried to do that here. But the steep slope triggers thin dark avalanches of dark sand that compete with the wind in shaping the sandy surface. (HiRISE ESP_043085_1670 NASA/JPL/Univ. of Arizona)
A Piece of Mars: This 0.96×0.54 km (0.6×0.33 mi) area shows ripples forming on a layer of dark gray material. In a few spots, the gray layer has been eroded away (probably by wind scour), revealing the lighter, tan-colored terrain below. Geologists call these exposures windows, because you can see through one layer to another that’s underneath. (HiRISE ESP_043086_1715 JPL/NASA/Univ. of Arizona)
A Piece of Mars: This 480×270 m (1575×886 ft) area shows a seemingly endless field of ripples. They’re big, about 50 m (164 ft) from crest to crest, and probably about 5 m (16 ft) high. Is there a knit or crochet pattern out there that looks like this? You could market it to some Mars aeolian scientists… (HiRISE ESP_042360_1755, NASA/JPL/Univ. of Arizona)
A Piece of Mars: Most of the scene (0.96×0.54 km or 0.6×0.34 mi) is one long slope of a dune. The crest is the line in the top right; the ground below is in the bottom left. If you ever walk along a dune or beach, you’ll see small ripples that can reach up to about a meter in length. But the ripples on this dune extend from the crest to the ground – they’re more than half a kilometer (more than a third of a mile) long! (HiRISE ESP_043098_1650 NASA/JPL/Univ. of Arizona)
A Piece of Mars: This 3.2×1.8 km (2×1.1 mi) area shows terrain covered by bright dust. Dark stripes are areas where wind has lightly scoured the surface, revealing the dark material beneath. Faint bright lines criss-cross the surface – these are tracks left by dust devils. The dust devils disturb the surface but don’t lift up enough dust to reveal the darker surface underneath. (HiRISE ESP_042691_2060, NASA/JPL/Univ. of Arizona)
A Piece of Mars: These “peas-in-a-pod” are dunes covered in long ripples (the scene is 960×480 m, or 0.6×0.3 mi). They’re a bit odd, surrounded by a rippled apron. It reminds me of melted-looking dunes that are common in high southern latitudes, but these are at 21.5ºN. Yet more Mars mysteries to solve… (HiRISE ESP_042697_2055 NASA/JPL/Univ. of Arizona).
A Piece of Mars: This scene is 0.96×0.54 km (0.60×0.34 mi) across. There’s an old river valley running across it. The walls of the valley have been eroded and there’s a washboard pattern with a wavelength of ~6m (20 ft). When I first saw this image I thought it was exposed, tilted layers, but a closer look reveals a much smaller (and younger) set of ripples that are similarly oriented and almost certainly formed by the wind. What do you think? (HiRISE ESP_041982_1535, NASA/JPL/Univ. of Arizona)
There are three states of parental organization. I’ve done all three on occasion, but I do have my tendencies. We all have our way of getting things done. Here they are:
1. Super organized parent: These are the folks who know where every thing is, and everything has its place (you can tell where the place is, because the things are there, in their place). Appointments are made ahead of time, marked on a calendar, all people who should know about said appointments are informed (possibly more than once), and all required attendants show up at said appointments on time. My mother in law is one of these people. Sometimes she’ll find a stray kid’s sock that we left behind at her house, and she’ll keep it and tell us about it, because to her this is a Problem. She’s actually surprised at stray socks, because in her world they are an oddity. They are worth discussion, and they are even pondered. I’m rarely this organized, but it does happen on occasion, and then everybody is surprised (more discussion and pondering usually ensues).
2. Sporadically-organized parent: This is the parent who remembers to register for summer camp the day before it begins, hoping it’s not too late. The parent who once bought a package of wipes for the car, and who might even know if it’s getting close to empty, but might forget to buy more on their next shopping trip. The parent who usually does the kids’ laundry on time, but every once in a while forgets and the next morning has to go digging through the drawers to find clothes for the kids that aren’t too torn or too small, all while urging sleepy children to wake up and get their teeth brushed. I usually fall into this camp. Hey, this time I registered the kids for gymnastics a whole week ahead of time. Go me!
3. Disorganized parent: You know what this is, I don’t have to tell you. We all have our fuzzy moments. (OK, maybe my mother in law doesn’t. She has skillz.) I sometimes slip in this direction. But here’s thing thing about being in a disorganized parental state, which is why I don’t worry about it too much: sometimes it works for me. Take what happened to me tonight (which prompted me to write this whole thing). My oldest is 5, and he’s got some sort of stomach bug. On the way home from my in-laws’ this evening, he announced that he had to throw up. I’m surprised by this, because he hasn’t thrown up all day, so I haven’t thought about this ahead of time (I’m not the super-organized type, remember). But. On the floor of my (messy) car, among other oddities, is a plastic bag with a bunch of party favors that I got for my kid’s birthday party. Not the birthday party we threw a week ago, but the one last year, because I guess I forgot about those party favors and they didn’t make it into the party favor bags for the guests. So yes, there’s been a plastic bag with about 20 little plastic rings with big googly eyes on them sitting on the front passenger floor of my car for about a year. So I pull over, dump the googly-eyed rings on the car floor, and get the bag to him, in time to get most of the throwup in it. I’m very grateful the bag didn’t have holes.
See, if I’d been super organized, I’d have had a box of Ziploc bags or something at all times, plus some wipes. That would have been nice, but that’s also a lot of spare cycles my tired brain doesn’t want to have to worry about, along with all the other spare cycles that being super organized requires.
If I’d been sporadically-organized, I’d have eventually found that bag of googly-eyed rings sometime over the last year (perhaps while cleaning my car – don’t laugh, I actually cleaned out my car once) and put it somewhere sensible (wherever one stores such things, to be found in time for the next year’s birthday party – because they didn’t make it in this year either), and thrown away the bag. So then I would have had nothing to hand my kid. I’d have been screwed. (On the other hand, I might have had some wipes on hand, which would have been nice.)
But no, in this case I was simply disorganized. So I had the bag, and the evening was not a complete parental failure. Disorganized parenting FTW!
A Piece of Mars: The dark dunes in this 0.96×0.54 km (0.60×0.34 mi) scene are slowly migrating towards the lower left. Look closer and you’ll see brighter ripples between the dunes – the biggest ones are ~8m (26 ft) apart. They form trains in the wake of the dunes. Why? This is where the dunes previously marched on by, obliterating the ripples as they went. Ripples form again after the dunes pass by, growing in size and regularity with time. (HiRISE ESP_01746_2570, NASA/JPL/Univ. of Arizona)
Today I’ve got something different. Today NASA announced the discovery of hydrated salts in some dark slope features that form during the spring on Mars. These “recurring slope lineae”, or RSLs, were discovered a few years back, and they form on steep slopes every spring in a few places on Mars. There’s been a big debate over whether these things are formed by flowing water (which would be big news: flowing water on Mars today, right now, where we can witness and study it, not just billions of years ago in the distant past – these RSLs could be an environment where life could exist) or whether they’re just boring dry flows of sand or dust that only turn dark because for some weird reason the bright dust gets kicked off the surface (things like that also happen on Mars in other places).
But now they’ve found hydrated salts, which only form in the presence of water. So that means these RSLs are associated with water. They’re not just dry sandy avalanches. So now they’re places we need to pay more attention to, partly because we might find life there (yay!) and also because we need to be careful not to kill it or infect it with our biological cooties (boo!).
So in honor of this new discovery, I’m giving you a list of some of the words we’ve used to describe landforms on Mars. It’s true, we planetary scientists have a penchant for acronyms and names that don’t roll off the tongue. It may be partly because we lack imagination, but it’s also partly to cover ourselves (CYA, there’s another 3 letter acronym), so that we don’t pick a name that makes us assume something about what process forms that feature. Thus we have the mighty “recurring slope lineae” instead of something more catchy like “springtime slush”, because what if that name stuck and they turned out to be something much less exciting? Then we’d have to call them by the wrong name, and it would be the Pluto demotion fiasco all over again. Nobody wants that.
With some luck these RSLs will be renamed something more catchy. Most likely the IAU (another acronym!) will give them names relating to water features on Earth, like naming them after famous springs or fountains or something. That won’t happen for years to come. In the meantime, you can make your very own 3 letter acronym from the list above and play at martian geology. Have fun!