Exhumed dunes!
Published 8/7/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: The large dunes in the middle of this 375x450 m (0.23x0.28 mi) scene run along a valley (the small dunes at top and bottom are on high ground). What's amazing about this is that the ends of the large dunes extend into the valley walls. That is, they're covered by the stuff in the valley walls. Usually dunes sit on top of all the other geologic structures, but not here. These dunes formed a long time ago. And then a lot of sediment piled on top of them - but without destroying them (which is what usually happens on Earth, so we don't see this sort of thing here). And then those sediments were later eroded to make the 0.5 km wide valley, revealing the buried dunes. Look at all this geology we can do from space! (HiRISE ESP_018347_1660, NASA/JPL/Univ. of Arizona) read more ❯

SETI Institute-Unistellar parceira promete revolucionar a astronomia amadora
Published 8/3/2017 in Franck Marchis Blog Author Franck Marchis
19 de julho de 2017 -Mountain View, CA e Meyreuil, França: o Instituto SETI e a startup francesa Unistellar, anunciaram hoje uma parceria para comercializar um novo telescópio que promete oferecer uma visão incomparável do cosmos aos astrônomos amadores e oferecer a oportunidade de contribuir diretamente para ciência de ponta. O novo eVscope™ da Unistellar aproveita a tecnologia de imagem "Enhanced Vision" e agora oferece três recursos únicos nunca antes oferecidos em um instrumento compacto de mercado de massa graças a esta parceria: O Enhanced Vision produz imagens extremamente nitidas e detalhadas de objetos astronômicos até mesmo fracos,... read more ❯

Mars' giant bubble wrap
Published 7/31/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: This 0.7x0.5 km (0.43x.31 mi) scene shows Mars' giant yellow bubble wrap, with each "bubble" about 100 m across (seriously, don't you want to pop them?). These are actually a type of dune called a "dome dune", and they're about as small as this type of martian dune can get. Dome dunes form where the wind blows from one main wind direction, but shifts a bit in direction (we call it a "wide unimodal distribution"). These are near the north pole, and at this time of year (early northern spring), they're still covered in winter frost, with a light powdering of dust to make them yellow. You can see spots where the underlying dark sand is just beginning to show through as the sun sublimates the ice. (HiRISE, ESP_050886_2565, JPL/NASA/Univ. of Arizona). read more ❯

Cross-strata or not?
Published 7/25/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: Sand dunes are one of the few sedimentary phenomena that leave behind layers that aren't horizontal. They tend to have a characteristic lean to them (and we call them cross-strata). So when I see something that looks like tilted layers on Mars, I take notice. This 0.625x0.5 km (0.39x0.31 mi) scene shows a steep slope, the side of a narrow graben system called Sirenum Fossae. The cliff starts at the top where overhanging rocks make shadows, and it ends at the bottom where there are small dunes. Along the slope are many narrow gullies from where sediment has slid downslope. And if you look carefully (click to see the whole image), you'll see small diagonal lines aligned from upper-right to lower-left. So are those diagnoal lines the strata produced by ancient dunes? Probably not. I think not, mostly because you can still see those diagonal lines... read more ❯

Asociación de SETI Institute y Unistellar promete revolucionar astronomía amateur
Published 7/23/2017 in Franck Marchis Blog Author Franck Marchis
SETI Institute y organización francesa Unistellar, anunciaron una asociación para comercializar un nuevo telescopio que promete entregar imágenes sin paralelo del cosmo a los astrónomos amateurs y proporcionar la oportunidad de contribuir de forma directa a ciencia de punta. Nuevo eVscope™ de Unistelar eleva la tecnología de imagen “visión mejorada”  y proporciona tres características únicas nunca antes incluidas en instrumentos compactos para el mercado masivo, gracias a esta asociación. La “visión mejorada” (Enhance Vision) produce imágenes extremadamente precisas y detalladas de objetos astronómicos débiles al acumular su luz y proyectarla en el ocular del telescopio.... read more ❯

SETI Institute-Unistellar Partnership Promises to Revolutionize Amateur Astronomy
Published 7/22/2017 in Franck Marchis Blog Author Franck Marchis
July 19 2017 -Mountain View, CA & Meyreuil, France: The SETI Institute and French startup Unistellar, announced a partnership today to commercialize a new telescope that promises to deliver an unparalleled view of the cosmos to amateur astronomers, and provide the opportunity to contribute directly to cutting-edge science. Unistellar’s new eVscope™   leverages “Enhanced Vision” imaging technology and now provides three unique features never before offered in a compact mass-market instrument thanks to this partnership: Enhanced Vision produces extremely sharp, detailed images of even faint astronomical objects by accumulating their light and projecting... read more ❯

L’institut SETI et Unistellar s’associent pour révolutionner l’Astronomie et la Science Citoyenne
Published 7/21/2017 in Franck Marchis Blog Author Franck Marchis
19 juillet 2017 Mountain View, Californie, Etats Unis et Meyreuil, France — L’Institut SETI et la start-up française Unistellar annoncent aujourd’hui un partenariat, dans le but de commercialiser un nouveau télescope offrant aux astronomes amateurs une qualité d’observation du ciel sans précédent, ainsi que l’opportunité de contribuer de façon déterminante aux dernières découvertes des astronomes professionnels.   L’eVscopeTM (Enhanced Vision Telescope) d’Unistellar atteint cet objectif grâce à trois fonctions qui n’ont jamais encore été rassemblées au sein d’un appareil compact et destiné au grand public: La Vision Amplifiée, qui fournit des images exceptionnelles, fines et détaillées des objets astronomiques les plus lointains en accumulant la lumière et en la projetant directement dans l’oculaire du télescope. La technologie de la Vision Amplifiée remplace la capacité qu’ont les grands télescopes à accumuler la lumière, et fournit ainsi à l’oculaire de... read more ❯

Westward moving
Published 7/17/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: No great scientific insights today, just a really lovely view of bright TARs and some very dark sand in this 0.875x0.5 km (0.54x0.31 mi) scene. Only one major wind acts in this region, moving sediment toward the west. Jezero crater, a prime landing site candidate for the Mars 2020 rover, lies 50 km to the west, so some of the sand blown into that crater passed through this area at some point in the past. (HiRISE, ESP_050899_1985, NASA/JPL/Univ. of Arizona) read more ❯

Experimenting with 3D views
Published 7/13/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: I often use JMARS to visualize Mars data sets, especially images. They've recently updated their 3D layer, allowing folks to make lovely vistas by overlaying DTMs with images. I'm new at this, but I'll experiment and see what I can do to make nice views. Here's a series of barchan dunes marching away from a tall stack of layers in Becquerel crater, with no vertical exaggeration. (HiRISE, DTEEC_045140_2015_044784_2015, NASA/JPL/Univ. of Arizona) read more ❯

Reversing slip faces
Published 7/10/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: This 523x750 m (0.32x0.47 mi) scene shows a large dune. It's quite colorful for some reason, although it's partially false-color. What caught my eye is that the slip face on this dune has reversed direction, which is somewhat rare on Mars (but common on Earth). The main sand-moving wind blows from the right, forming a long avalanching slope (you can see long bright lines of grain fall slips at the lower center). But at some point a wind blew from the left, forming a small slip face in the opposite direction. Although many other wind directions have also help to build this dune, those two are the main winds apparent here. (HiRISE ESP_050887_2225, NASA/JPL/Univ. of Arizona) read more ❯

The real tetrahedrons of Mars
Published 6/19/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: The real tetrahedrons of Mars are dunes, built by winds blowing sand from more than one direction. This 0.5x0.5 km (0.31x0.31 mi) area shows a dune formed from two winds that are about 90 degrees apart: one blowing from the bottom and one blowing from the right. This makes the dune have two slip faces, which is a rare occurrence on Earth dunes. (Earth dunes are complicated by superposed secondary dunes that interfere with and obscure this pattern. Or if they're small enough to not have those secondary dunes, then they are changing fast enough that one slip face will quickly erase the other. I've only ever seen two slip faces at once for very short periods in Earth dunes - they don't last.) Here, the two winds have worked together to form a little spit of sand off to the upper left. The result is... read more ❯

The thinnest landslides
Published 6/15/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: In the dustiest regions of Mars, steep slopes occasionally produce very thin avalanches of dust, revealing a darker surface under the top layer of dust. This shows one that is 610 m (0.38 mi) long, running from its tiny point of initiation near the top of the slope down to the bottom of the slope where accumulated landslides have slowly buried old windblown dunes (or TARs). These landslides occur every spring, and may be triggered by sublimation of small accumulations of winter ice, or perhaps by the wind. This one formed some time between May 7, 2012 and May 22, 2013, as it appeared between two successive images of this spot. It's still there today, most recently imaged on May 5, 2017, slowly accumulating dust until it fades into the background with the rest of the slope. (HiRISE ESP_035307_2115, NASA/JPL/Univ. of Arizona) read more ❯

Dunes fighting for survival
Published 6/5/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: Having a bad day? You're in good company with these dunes in this 0.96x0.48 km (0.6x0.3 mi) scene. The gray barchanoid dunes are covered in ripples, as the wind valiantly tries to push the sand to the dune crests. But they are besieged by other processes at work. Dark scribbles show how dust devils have swept by, removing dust and probably scattering a little bit of the sand. The steep slip faces are not covered in dry avalanches typical of active dunes, but rather they appear eroded, as if some force locked the dune in place and started eroding the surface wherever ripples couldn't rescue it. Splotches on the tan ground between the dunes, and narrow furrows attest to seasonal ice reworking the surface. And in this great battle, what I wonder is: can those dunes have formed like this amidst such turmoil, or are they... read more ❯

Weird and wild southern polar dunes
Published 5/29/2017 in Lori Fenton's Blog Author lfenton
A Piece of Mars: This 0.96x0.48 km (0.6x0.3 mi) scene shows a bit of a south polar dune field. The more recently-active dark sand is rippled, but there are bright splotches where something else has happened. Presumably it's ground ice that sublimated away explosively, as happens at many high latitude locations on Mars, only here the dunes are stabilized enough that those spots aren't eroded away by wind activity every summer. Because the dunes aren't active, their crests have diminished to subtle bumps on the landscape (would you even know they were dunes if I hadn't told you? Look at the whole HiRISE image to be sure!) (HiRISE ESP_013224_1080, NASA/JPL/Univ. of Arizona) read more ❯