Wednesday, July 30, 2014

Hrad Vallis


The channel in this VIS image is a portion of Hrad Vallis.

Orbit Number: 54899 Latitude: 36.0662 Longitude: 140.235 Instrument: VIS Captured: 2014-04-30 05:19

Photo credit: NASA/JPL-Caltech/Arizona State University

Tuesday, July 29, 2014

Hills Near Phlegra Dorsa


The term "colles" means hills. The hills in this VIS image are located on the northern plains near Phlegra Dorsa.

Orbit Number: 54886 Latitude: 41.5743 Longitude: 155.977 Instrument: VIS Captured: 2014-04-29 03:37

Photo credit: NASA/JPL-Caltech/Arizona State University

Saturday, July 26, 2014

Rubicon Valles


This VIS image shows part of Rubicon Valles, a complex region of channels found on the northwestern flank of Alba Mons.

Orbit Number: 54883 Latitude: 45.1688 Longitude: 243.263 Instrument: VIS Captured: 2014-04-28 21:40

Photo credit: NASA/JPL-Caltech/Arizona State University

Friday, July 25, 2014

Layering in Utopia Planitia


Today's VIS image shows layering in the plains that comprise Utopia Planitia.

Orbit Number: 54875 Latitude: 38.2154 Longitude: 112.575 Instrument: VIS Captured: 2014-04-28 05:54

Photo credit: NASA/JPL-Caltech/Arizona State University

Thursday, July 24, 2014

Lyot Crater Dunes


The dunes in this VIS image are located on the floor of Lyot Crater.

Orbit Number: 54853 Latitude: 50.2638 Longitude: 29.1544 Instrument: VIS Captured: 2014-04-26 10:23

Photo credit: NASA/JPL-Caltech/Arizona State University

Wednesday, July 23, 2014

Coloe Fossae


The channels in this VIS image are part of Coloe Fossae, a series of linear depressions on the northeast margin of Terra Sabaea.

Orbit Number: 54852 Latitude: 39.1441 Longitude: 55.8792 Instrument: VIS Captured: 2014-04-26 08:28

Photo credit: NASA/JPL-Caltech/Arizona State University

Tuesday, July 22, 2014

Hills and Dunes in Olympia Undae


This VIS image shows part of the large dune field called Olympia Undae. There are hills in this region, and the dunes are concentrated in the lower elevations.

Orbit Number: 54834 Latitude: 79.539 Longitude: 233.335 Instrument: VIS Captured: 2014-04-24 20:41

Photo credit: NASA/JPL-Caltech/Arizona State University

Sunday, July 20, 2014

Surface of Planum Boreum


At Mars’ North Pole is a dome of icy layers ranging up to 2 kilometers thick, roughly analogous to the Earth’s ice caps in Greenland or Antarctica.

Although not visible here, the dome is characterized by incised spiraling troughs that reveal sequences of layers thought to reflect varying climate conditions over the time they were originally deposited. This image is of an area on the top surface of the polar dome between the troughs — vast, generally smooth, flat plains composed of a thin layer of very pure water ice. This image also shows that this thin ice layer has a rough texture, composed of knobs, ridges, and depressions on the scale of 1 - 10 meters.

This texture is only beginning to be studied with the high-resolution capabilities of HiRISE — the details of the texture varies around the polar cap, but the causes of the variation are not yet clear. This image has two particularly interesting features. One is that the surface dips into a depression towards the southwest, where the texture of the ice surface appears to change. The other is that there is a fracture or chain of pits in the southeast, which is a rare feature.

The brightness, composition, texture, and small-scale features of this ice layer that covers most of the polar dome are important as they influence the local energy balance (such the amount of sunlight reflected and absorbed), which in turn influences polar-wide climate and the stability of ice.

Image credit: NASA/JPL/University of Arizona

Note: For more information, see PIA18624: The Icy Surface of the North Polar Cap.

Saturday, July 19, 2014

Lonar Crater


Today's VIS image shows Lonar Crater. This crater has undergone very little modification since it formed, and so is one of the younger features in this region.

Orbit Number: 54828 Latitude: 72.999 Longitude: 38.4817 Instrument: VIS Captured: 2014-04-24 08:53

Photo credit: NASA/JPL-Caltech/Arizona State University

Note: Lonar Crater is located in Vastitas Borealis.

Crater Lake Sediments in Arabia Terra


This image shows some interesting fractured materials on the floor of an impact crater in Arabia Terra.

There is a channel entering the crater and exiting it (see CTX image). This channel, along with an unusual deposit on the lowest part of the floor, suggests that there was once an ancient lake that deposited sediments here.

Our enhanced-color sample shows layered deposits, some with polygonal patterns, as might be expected from lake sediments. The fracturing of these deposits might have resulted from the sudden breaching of the crater rim, draining the lake.

This is a stereo pair with ESP_035843_2165.

Image credit: NASA/JPL/University of Arizona

Note: For more information, see PIA18625: Ancient Lake Sediments in a Crater.

Friday, July 18, 2014

Dunes in Olympia Undae


Today's VIS image is part of Olympia Undae. Compare this to previous images and notice how uniform the dunes are in this region.

Orbit Number: 54827 Latitude: 81.1656 Longitude: 217.246 Instrument: VIS Captured: 2014-04-24 06:46

Photo credit: NASA/JPL-Caltech/Arizona State University

Ridges in Eridania Basin


Eridania Basin, located at the head of Maadim Vallis, has mounting geomorphic and spectral evidence that it may have been the site of an ancient inland sea.

This site presents interesting mineralogical and geological evidence for the past existence of a large aqueous system on Mars that could have been long lived, and may have been well suited for ancient life, and almost certainly contains important clues about the ancient climate.

In this HiRISE image, there are numerous dark ridges against a brighter substrate. These ridges could be cemented and topographically inverted fractures, although other origins (such as eskers, channels, or volcanic dikes) cannot be ruled out. One way to produce these ridges would be when fluids moved through the fractures, causing cementation and hardening. Later, erosion removed the softer rocks surrounding the fractures, while the more resistant cemented materials within the fractures were left standing higher, thus appearing inverted.

Image credit: NASA/JPL/University of Arizona

Note: For more information, see PIA18623: Ridges in Eridania Basin.