UAHiRISE (NASA MRO)

Sand dunes in the north polar regions of Mars show light coatings of dust blown across dark basaltic sand. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) NASA/JPL/University of Arizona https://uahirise.org/ESP_053129_2650

This HiRISE image captures a new, dated (within about a decade) impact crater that triggered a slope streak. When the meteoroid hit the surface and exploded to make the crater, it also destabilized the slope and initiated this avalanche. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_054066_1920

Sand dunes often accumulate in the floors of craters. In this region of Lyot Crater (Mars) there is a field of classic barchan dunes. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_053894_2295

These formations could be recent in geologic time and may mark habitable subsurface environments. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://uahirise.org/ESP_054649_1665

From the science rationale for this observation: “A high resolution image can help us resolve any small scale structure that can be used to determine what these mounds are.” Plus, what other forces besides the wind have eroded these mounds? Candor Chasma remains a favorite to image because of the fantastic stratigraphy. NASA/JPL/University of Arizona (285 km above the surface, less than 1 km top to bottom and north is to the right.) https://www.uahirise.org/ESP_051762_1750 ​

In early Martian summer, at the time we acquired this image, the dunes are almost free of their seasonal ice cover. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) NASA/JPL/University of Arizona (https://www.uahirise.org/ESP_053324_2570)

Hale Crater has a suite of wonderful features, such as this exposed bedrock. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) NASA/JPL/University of Arizona (https://uahirise.org/ESP_054701_1430)

Looking like pulled threads, these dunes march across a fabric of patterned ground. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.)

MRO keeps finding new impact sites on Mars. This one occurred within the dense secondary crater field of Corinto Crater. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) NASA/JPL/University of Arizona (https://uahirise.org/ESP_053745_1915)

There might have been lava flowing into the larger crater here, while the smaller crater shows distinct layers. NASA/JPL/University of Arizona (280 km above the surface, less than 5 km across). https://www.uahirise.org/ESP_051286_1785 ​

Ius Chasma is a major part of Valles Marineris, the largest canyon system in the solar system, and it about 938 kilometers in length. NASA/JPL/University of Arizona (288 km above the surface; 5 km across). https://www.uahirise.org/ESP_051195_1725 ​

This is a very rare formation within a crater: a shape like a much-beloved 1980s video game character. (Audio: www.tregibbs.com. Black and white images are less than 5 km across.) NASA/JPL/University of Arizona (280 km above the surface). https://www.uahirise.org/ESP_054515_1930

Often, a bolide breaks apart in the atmosphere and makes a tight cluster of new craters. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) NASA/JPL/University of Arizona

This image is an example of the principle of superposition: figuring out what happened first by looking at how features interact with each other. (Audio: www.tregibbs.com. Black and white images are 5 km across.) NASA/JPL/University of Arizona (https://www.uahirise.org/ESP_050849_1700)

Sand dunes in Valles Marineris can be impressive in size, with steep slopes that seem to climb and descend. Audio: www.tregibbs.com NASA/JPL/University of Arizona (262 km above the surface. Black and white is less than 5 km across; enhanced color is less than 1 km). https://www.uahirise.org/ESP_053739_1650

This could be an inverted stream system, which has an almost tree-like appearance (the meaning of “arborescence”). The science goal for this target was to to document this feature at at HiRISE scale, see whether it can be determined whether these are lithified. NASA/JPL/University of Arizona (257 km above the surface, less than 5 km across). https://www.uahirise.org/ESP_050993_1565 ​

This image is within Milankovic Crater, which is easy to see on Mars because it lies north of Olympus Mons and sits by itself in the flat plain of Vastitas Borealis. It is named after Milutin Milanković (1879–1958), a Serbian geophysicist and astrophysicist. NASA/JPL/University of Arizona (308 km above the surface and the scene is less than 1 km top to bottom and north is to the right). https://www.uahirise.org/ESP_050973_2350

There is a great deal of layering and faulting here, not too surprising as Candor Chasma is located with the giant Valles Marineris canyon system on Mars. NASA/JPL/University of Arizona (262 km above the surface, 5 km across). https://www.uahirise.org/ESP_054399_1695

The terrain is rough, the color is enhanced, but the view is **gorgeous**. Nili Fossae was once a candidate landing site for the Mars Science Laboratory (Curiosity) because of the clays located there. NASA/JPL/University of Arizona (294 km above the surface, less than 1 km top to bottom and north is to the right.) https://www.uahirise.org/ESP_050820_1970

This crater is located within Xanthe Terra, very close to Ravi Vallis. The crater is named after a town in Vietnam. NASA/JPL/University of Arizona (269 km above the surface and the scene is 5 km across. https://www.uahirise.org/ESP_050864_1795

Tyrrhena Terra is centered south of the Martian equator and immediately northeast of the giant Hellas basin. There are also possible clays in this region. NASA/JPL/University of Arizona (260 km above the surface and the scene is less than 1 km top to bottom and north is to the right.) https://www.uahirise.org/ESP_013898_1730

Bright ripples line the topography in this region, formed within a past climate. Dark dunes and sand streaks (composed of basaltic sand) have moved and filled lower areas, pushed by more recent winds from the top towards the bottom of this image. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_022250_2065

We can see higher standing ridges in this image, which indicates they are composed of more resistant material compared to the surrounding terrain. Roddy Crater is south of the western end of Valles Marineris (Mars). NASA/JPL/University of Arizona (262 km above the surface and the scene is under 5 km across.) https://www.uahirise.org/ESP_050653_1575

Some HiRISE images show strange-looking formations. Sometimes it helps to look at Context Camera images to understand the circumstances of a scene, which shows an impact crater with a central peak, and a collapse depression with concentric troughs just north of that peak. Our HiRISE picture is a close-up of one of those troughs, along with channels draining into the depression. On the floor of the trough is some grooved material that we typically see in middle latitude regions where there has been glacial flow. These depressions with concentric troughs exist elsewhere on Mars, and their origins remain a matter of debate. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_053734_1515

Gullies on Martian sand dunes, like these in Matara Crater, have been very active, with many flows in the last ten years. The flows typically occur when seasonal frost is present. Here, we see frost in and around two gullies, which have both been active before. There are no fresh flows so far this year, but HiRISE will keep watching! (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_054026_1300

This image shows a roundish crater with three channels breaching the rim and extending to the south. The crater has been filled by sediments and may have been an ancient lake. When the water began to overtop the crater rim, it would rapidly erode a channel and, at least, partially drain the lake. (Audio: www.tregibbs.com. Black and white images are 5 km across.) https://www.uahirise.org/ESP_053670_2180

The slip faces of these Martian polar dunes primarily face southeast but there also other orientations. Or perhaps, they're pondering their future as we ponder them... NASA/JPL/University of Arizona (319 km above the surface. The scene is 5 km top to bottom and north is to the right.) https://www.uahirise.org/ESP_050601_2555

This scene is located within a large impact crater to the west of Kaiser Crater. Both are located in the Noachis quadrangle of Mars. NASA/JPL/University of Arizona (252 km above the surface and the enhanced color scene is less than 1 km top to bottom and north is to the right.) https://www.uahirise.org/ESP_050559_1300

This clip features the enhanced color strip of an observation of a section of Sirenum Fossae (Mars), which is an over 2,700 km trough on the Red Planet. NASA/JPL/University of Arizona (257 km above the surface, less than 1 km top to bottom and north is to the left.) https://www.uahirise.org/ESP_013353_1475

This observation shows the plains to the northwest of the Argyre Region (Mars) with possible olivine-rich terrain. NASA/JPL/University of Arizona (256 km above the surface. Scene is less than 1 km top to bottom and north is to the right.) https://www.uahirise.org/ESP_013336_1430

This image is located within the massive Valles Marineris canyon system (Mars). NASA/JPL/University of Arizona (265 km above the surface, and the scene is less than 1 km across.) https://www.uahirise.org/ESP_050391_1755

Are the ridges fluvial sedimentary rock bodies and is there layering within the pits? NASA/JPL/University of Arizona (328 km above the surface. Enhanced color is less than 1 km top to bottom and north is to the right.) https://www.uahirise.org/ESP_050427_2200

Based upon where the layers are exposed, we can tell that the dark layers formed first followed by the light layers. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://uahirise.org/PSP_007917_1650

How do these ridges stand in positive relief after billions of years of erosion? (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_053752_1540

Some of the ground has parallel dark and light stripes and within those dark stripes are piles of boulders at regular intervals. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_053924_2550

“As her fate, she accepted the world of ice, shining, shimmering, dead; she resigned herself to the triumph of glaciers and the death of the world.” ― Anna Kavan, Ice NASA/JPL/University of Arizona (274 km above the surface. Scene is 5 km across.) https://uahirise.org/ESP_050218_0930

NASA/JPL/University of Arizona (265 km above the surface, less than 1 km top to bottom and north is to the right.) https://uahirise.org/ESP_050338_1720

Alluvial fans on Mars are thought to be ancient and record past episodes of flowing water. NASA/JPL/University of Arizona (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://uahirise.org/ESP_054117_1585

Barlow Crater is in the mid latitudes of Mars, to the northwest of the Hellas impact basin. It is *not* named after Mr. Barlow in "Salem's Lot." NASA/JPL/University of Arizona (256 km above the surface; scene is less than 1 km top to bottom and north is to the right.) https://www.uahirise.org/ESP_013053_1660

Worn away by the wind, the bedrock reveals its geologic history. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/PSP_003418_1865

These light-toned mounds generally contain sulfates, which are salts of sulfuric acid that form when water is evaporating. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://uahirise.org/ESP_016712_1760

While it certainly hasn't gone anywhere, a new image of the Phoenix lander shows us how much change has occurred in five Mars years. (Audio: www.tregibbs.com. Enhanced color images are 1 km across.) https://uahirise.org/ESP_053451_2485

One upside of recognizing and noting this ice is that future astronauts will have plenty of drinking water. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://uahirise.org/ESP_053642_2225

This crater may have formed in a region rich in ground water, which flowed down its wall and eroded numerous gullies in the process. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://uahirise.org/ESP_021741_1415

“I’m fascinated by the narrative of geology...I keep a rock hammer in my car.” – Marianne Wiggins Breccias are large concentrations of jumbled rock. NASA/JPL/University of Arizona (278 km above the surface. Scene is 5 km across) https://www.uahirise.org/ESP_050323_1875

This observation shows bedrock that is several kilometers below the top of the giant Valles Marineris canyons. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_013784_1710

As beautiful as this pattern is, the streaks will fade away over decades as more dust settles out of the Martian sky. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_053518_1955

Wait, what? (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/ESP_053222_2150

An excellent candidate for recurring slope lineae. Will we see them change over time? NASA/JPL/University of Arizona (268 km above the surface. Enhanced color is less than 1 km top to bottom and north is to the right) https://www.uahirise.org/ESP_049268_1695

Over time thin cracks develop and coalesce into a honeycomb network, with a few meters spacing between neighboring them. (Audio: www.tregibbs.com. Black and white images are 5 km across; enhanced color images are 1 km.) https://www.uahirise.org/PSP_008883_2245