Friday, May 31, 2013

Hottah Outcrop and Streambed


NASA's Curiosity rover found evidence for an ancient, flowing stream on Mars at a few sites, including the rock outcrop pictured here, which the science team has named "Hottah" after Hottah Lake in Canada's Northwest Territories. It may look like a broken sidewalk, but this geological feature on Mars is actually exposed bedrock made up of smaller fragments cemented together, or what geologists call a sedimentary conglomerate. Scientists theorize that the bedrock was disrupted in the past, giving it the tilted angle, most likely via impacts from meteorites.

NASA's Mars Science Laboratory (MSL) Curiosity rover found evidence for ancient, water-transported sediment on Mars at a few sites, including the rock outcrop pictured here, named "Hottah." Rounded pebbles within this sedimentary conglomerate indicate sustained abrasion of rock fragments within water flows that crossed Gale Crater.

The key evidence for the ancient stream comes from the size and rounded shape of the gravel in and around the bedrock. Hottah has pieces of gravel embedded in it, called clasts, up to a couple inches (few centimeters) in size and located within a matrix of sand-sized material. Some of the clasts are round in shape, leading the science team to conclude they were transported by a vigorous flow of water. The grains are too large to have been moved by wind. Erosion of the outcrop results in gravel clasts that protrude from the outcrop and ultimately fall onto the ground, creating the gravel pile in the left foreground. The scale bar at lower right is 5 centimeters (2 inches).

This view of Hottah is a mosaic of images taken by the right (telephoto-lens) camera of the Mast Camera instrument (Mastcam) on Curiosity during the 39th Martian day, or sol, of the rover's work on Mars (September 14, 2012 PDT/September 15 GMT). It has been enhanced for presentation in white-balanced color, which yields a view as if the rock were seen under outdoor lighting conditions on Earth, which is useful for scientists to distinguish rocks by color in familiar lighting. A "raw color" view of Hottah, showing the colors as recorded by the camera on Mars, is at PIA16156. A stereo view is at PIA16223.

Image credit: NASA/JPL-Caltech/MSSS

Note: For more information, see Pebbly Rocks Testify to Old Streambed on Mars.

Saturday, May 18, 2013

'Esperance' Altered by Wet History


The pale rock in the upper center of this image, about the size of a human forearm, includes a target called "Esperance," which was inspected by NASA's Mars Exploration Rover Opportunity. Data from the rover's alpha particle X-ray spectrometer (APXS) indicate that Esperance's composition is higher in aluminum and silica, and lower in calcium and iron, than other rocks Opportunity has examined in more than nine years on Mars. Preliminary interpretation points to clay mineral content due to intensive alteration by water.

This image is a composite of three exposures taken by Opportunity's panoramic camera (Pancam) during the 3,262nd Martian day, or sol, of the rover's work on Mars (March 28, 2013). The component images were taken through three different Pancam filters -- centered on wavelengths of 753 nanometers (near-infrared), 535 nanometers (green) and 432 nanometers (violet). The view is presented in false color to make some differences between materials easier to see.

Image credit: NASA/JPL-Caltech/Cornell/Arizona State University

Note: For more information, see Mars Rover Opportunity Examines Clay Clues in Rock.

Saturday, May 11, 2013

Dusty Skies for Opportunity Between Sols 3296 and 3301


These two images, taken five Martian days (sols) apart by the front hazard-avoidance camera on NASA's Mars Exploration Rover Opportunity, document the Martian sky above the rover's Endeavour Crater location becoming dustier.

The image on the left was taken during Sol 3296 of Opportunity's mission on Mars (May 2, 2013). The one on the right was taken during Sol 3301 (May 7, 2013) with the rover at the same location but its arm in a different position. In between those dates, local-scale dust storm activity west of Opportunity's location had reduced clarity of the sky over Opportunity. Effects can be seen in the Sol 3301 image. Note the softened shadow of the rover and the obscured horizon on the right.

The location of the rover when these images were taken was on the "Cape York" segment of the western rim of Endurance Crater. During this period Curiosity was investigating the rock target "Esperance," which is on the pale patch of rock just to the left of the shadow of the rover's arm. After that investigation, the last planned for Cape York, the rover team plans to drive Curiosity toward a segment of the rim to the south, called "Solander Point."

Photo credit: NASA/JPL-Caltech

Friday, May 10, 2013

Gale Crater (2005) #26


During the month of April Mars will be in conjunction relative to the Earth. This means the Sun is in the line-of-sight between Earth and Mars, and communication between the two planets is almost impossible. For conjunction, the rovers and orbiting spacecraft at Mars continue to operate, but do not send the data to Earth. This recorded data will be sent to Earth when Mars moves away from the sun and the line-of-sight between Earth and Mars is reestablished. During conjunction the THEMIS image of the day will be a visual tour of Gale Crater, the location of the newest rover Curiosity.

Backtracking a bit, this image shows the large channel in the upper left of the frame. Just below the brighter material of Mt. Sharp is the start of the arced edge of material we saw in yesterday's image (top right).

Orbit Number: 17158 Latitude: -5.84154 Longitude: 137.095 Instrument: VIS Captured: 2005-10-27 01:52

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

Note: This is the 26th in a series of images in which the THEMIS team is currently showing the central region of Gale Crater, starting at the eastern rim and moving past Mount Sharp to the western rim. Starting with image #23, the images are being shown from west to east, slightly south of the previous series. All of the images in this series I will name "Gale Crater (XXXX) #Y", in which XXXX is the year in which the photo was actually taken, and Y is the sequence number (1 through...).

Sulci Gordii Closeups


Close-up of the ‘sulci’ features that define Sulci Gordii. Sulci are roughly parallel sets of ridges and valleys likely formed through tectonic and erosional processes. A prominent fault line extends along the left side of the image, while smooth lava plains overlay parts of the sulci.

Sulci Gordii is an aureole deposit resulting from the dramatic collapse of the flank of Olympus Mons in its distant past.

The image was taken by the High Resolution Stereo Camera on ESA’s Mars Express on 23 January 2013 (orbit 11531), with a ground resolution of about 31 m per pixel. Sulci Gordii lies at approximately 17°N / 234°E, about 200 km east of Olympus Mons.


This image focuses on a region on the western limb of Sulci Gordii (top center-right on the corresponding main image). It shows clearly in the foreground the near-parallel characteristic of the ridges and valleys that define geological features called sulci. Close inspection of the ridges reveals dark streaks along their faces, evidence of numerous small landslides of rocky and dusty debris.

Sulci Gordii is an aureole deposit resulting from the dramatic collapse of the flank of Olympus Mons in its distant past.

The image was taken by the High Resolution Stereo Camera on ESA’s Mars Express on 23 January 2013 (orbit 11531), with a ground resolution of about 31 m per pixel. Sulci Gordii lies at approximately 17°N / 234°E, about 200 km east of Olympus Mons.

Photo credits: (Top) ESA/DLR/FU Berlin (G. Neukum); (Bottom) ESA/DLR/FU Berlin (G. Neukum).

Thursday, May 9, 2013

Gale Crater (2009) #25


During the month of April Mars will be in conjunction relative to the Earth. This means the Sun is in the line-of-sight between Earth and Mars, and communication between the two planets is almost impossible. For conjunction, the rovers and orbiting spacecraft at Mars continue to operate, but do not send the data to Earth. This recorded data will be sent to Earth when Mars moves away from the sun and the line-of-sight between Earth and Mars is reestablished. During conjunction the THEMIS image of the day will be a visual tour of Gale Crater, the location of the newest rover Curiosity.

As we begin to move back eastward across the southern part of Gale Crater, this image shows more of the dark material deposited from the large channel through the SW rim of the crater. In this image that material has a sharp edge (center of frame) where it overlays the crater floor.

Orbit Number: 31708 Latitude: -5.79428 Longitude: 137.335 Instrument: VIS Captured: 2009-02-06 02:41

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

Note: This is the 25th in a series of images in which the THEMIS team is currently showing the central region of Gale Crater, starting at the eastern rim and moving past Mount Sharp to the western rim. Starting with image #23, the images are being shown from west to east, slightly south of the previous series. All of the images in this series I will name "Gale Crater (XXXX) #Y", in which XXXX is the year in which the photo was actually taken, and Y is the sequence number (1 through...).

Sulci Gordii Channels and Fractures


This perspective view focuses on the southernmost portion of Sulci Gordii, which highlights jagged fractures and fault lines, as well as some sinuous channels that were likely widened by short-lived lava flows or water. In the foreground to the left, a channel can be seen that is abruptly truncated by a tectonic fault. Another channel in the center foreground has also clearly undergone a complex fracturing history. To the upper right, a few rocky blocks appear like islands in a sea of ancient lava plains, with the ‘shoreline’ at the top of the image part of the ridge and valley system of Sulci Gordii.

The image was taken by the High Resolution Stereo Camera on ESA’s Mars Express on 23 January 2013 (orbit 11531), with a ground resolution of about 31 m per pixel. Sulci Gordii lies at approximately 17°N / 234°E, about 200 km east of Olympus Mons.

Photo credit: ESA/DLR/FU Berlin (G. Neukum)

Wednesday, May 8, 2013

Gale Crater (2009) #24


During the month of April Mars will be in conjunction relative to the Earth. This means the Sun is in the line-of-sight between Earth and Mars, and communication between the two planets is almost impossible. For conjunction, the rovers and orbiting spacecraft at Mars continue to operate, but do not send the data to Earth. This recorded data will be sent to Earth when Mars moves away from the sun and the line-of-sight between Earth and Mars is reestablished. During conjunction the THEMIS image of the day will be a visual tour of Gale Crater, the location of the newest rover Curiosity.

In this image the large channel from the previous image is just visible at the bottom left of the frame. The rough appearing dark material at the bottom of the image was likely deposited by the large channel. This image shows how close that material is to Mt. Sharp and also how different the two deposits appear in a visible wavelength image.

Orbit Number: 33966 Latitude: -5.24338 Longitude: 137.195 Instrument: VIS Captured: 2009-08-11 01:10

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

Note: This is the 24th in a series of images in which the THEMIS team is currently showing the central region of Gale Crater, starting at the eastern rim and moving past Mount Sharp to the western rim. Starting with image #23, the images are being shown from west to east, slightly south of the previous series. All of the images in this series I will name "Gale Crater (XXXX) #Y", in which XXXX is the year in which the photo was actually taken, and Y is the sequence number (1 through...).

Sulci Gordii Topographical Map


This color-coded overhead view is based on an ESA’s Mars Express High Resolution Stereo Camera digital terrain model of the Sulci Gordii region of Mars, which lies about 200 km east of Olympus Mons. Sulci Gordii was imaged on 23 January 2013 (orbit 11531), with a ground resolution of approximately 31 m per pixel.

Image credit: ESA/DLR/FU Berlin (G. Neukum)

Tuesday, May 7, 2013

Gale Crater (2009) #23


During the month of April Mars will be in conjunction relative to the Earth. This means the Sun is in the line-of-sight between Earth and Mars, and communication between the two planets is almost impossible. For conjunction, the rovers and orbiting spacecraft at Mars continue to operate, but do not send the data to Earth. This recorded data will be sent to Earth when Mars moves away from the sun and the line-of-sight between Earth and Mars is reestablished. During conjunction the THEMIS image of the day will be a visual tour of Gale Crater, the location of the newest rover Curiosity.

This image shows the southwestern floor of Gale Crater. A fairly large channel that dissects the crater rim is visible entering from the bottom of the frame and continuing northward.

Orbit Number: 34877 Latitude: -5.2813 Longitude: 137.111 Instrument: VIS Captured: 2009-10-25 01:17

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

Note: This is the 23rd in a series of images in which the THEMIS team is currently showing the central region of Gale Crater, starting at the eastern rim and moving past Mount Sharp to the western rim. Starting with this image (#23), the images are being shown from west to east, slightly south of the previous series. All of the images in this series I will name "Gale Crater (XXXX) #Y", in which XXXX is the year in which the photo was actually taken, and Y is the sequence number (1 through...).

Craters Muara and Tarrafal

From the USGS Astrogeology Science Center:

The Working Group for Planetary System Nomenclature has approved new names for two craters on Mars: Muara and Tarrafal. For more information, see the Gazetteer of Planetary Nomenclature.

Sulci Gordii


ESA’s Mars Express imaged the Sulci Gordii region of Mars with its High Resolution Stereo Camera on 23 January 2013 (orbit 11531), with a ground resolution of about 31 m per pixel. Sulci Gordii lies at approximately 17°N / 234°E, about 200 km east of Olympus Mons.

The feature is an ‘aureole’ deposit resulting from a massive landslide that sloughed away from the flanks of Olympus Mons in its distant past. The complex scene is dominated by a series of roughly parallel ridges and valleys (called sulci), with lava or water-carved channels in the southern most (left) portion of the image. Smooth, young volcanic lava flows overlay parts of the sulci.

Photo credit: ESA/DLR/FU Berlin (G. Neukum)

Monday, May 6, 2013

Olivine-Bearing Dune Fields and Wall Rock in Coprates Chasma


In this image, lower wall rock spurs are found that spread dark materials onto a dune field, suggesting local wall materials are a nearby sediment source for dunes. This subimage shows the interface between wall materials and dunes in the northwest portion of the main image

Dune sand, wall spurs, and boulders are all partially composed of olivine (according to CRISM data), a common mineral formed in volcanic processes, supporting the notion for local sourcing of dunes.

Olivine is highly susceptible to weathering by aqueous processes indicating these dunes and the wall debris formed after any such activity. Interestingly, clay minerals (known as phyllosilicates) are detected farther up the wall suggesting that aqueous alteration of wall materials has occurred in the ancient past.

Photo credit: NASA/JPL/University of Arizona

Sunday, May 5, 2013

Sedimentary Bedrock Diversity in Terby Crater


Terby Crater, sitting on the northern rim of Hellas Basin, has been filled by sedimentary deposits, perhaps deposited by or in water.

The northeast portion of these layers have been eroded by the wind, exposing the layers. The enhanced-color subimage is a sample of these materials, in which the different colors and textures represent different rock types.

Be sure to take a look at the stereo anaglyph for a 3D view of the landscape.

This is a stereo pair with ESP_031278_1525.

Photo credit: NASA/JPL/University of Arizona

Saturday, May 4, 2013

Gale Crater (2010) #22


During the month of April Mars will be in conjunction relative to the Earth. This means the Sun is in the line-of-sight between Earth and Mars, and communication between the two planets is almost impossible. For conjunction, the rovers and orbiting spacecraft at Mars continue to operate, but do not send the data to Earth. This recorded data will be sent to Earth when Mars moves away from the sun and the line-of-sight between Earth and Mars is reestablished. During conjunction the THEMIS image of the day will be a visual tour of Gale Crater, the location of the newest rover Curiosity.

Today's image shows the western rim of Gale Crater. Several channels dissect the rim of the crater.

Orbit Number: 36487 Latitude: -5.08574 Longitude: 136.679 Instrument: VIS Captured: 2010-03-06 14:39

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

Note: This is the 22nd in a series of images in which the THEMIS team is currently showing the central region of Gale Crater, starting at the eastern rim and moving past Mount Sharp to the western rim. Starting with image #9, the images are being shown from east to west. All of the images in this series I will name "Gale Crater (XXXX) #Y", in which XXXX is the year in which the photo was actually taken, and Y is the sequence number (1 through...).

Unusual Topography in Acidalia Planitia


This image covers many shallow irregular pits with raised rims, concentrated along ridges and other topographic features. How did these odd features form?

One idea is that they could be from sublimation of shallow lenses of nearly pure ice, but why do the pits have raised rims? They can't be impact craters with such fortuitous alignment and irregular margins. They aren't wind-blown deposits because there are many boulders, too big to be moved by the wind. There are younger wind-blown drifts on top of the pits, and there's no clear connection to volcanism.

Some speculate that there were ancient oceans over this region--could that somehow explain these features? Ancient glaciation is another possibility, perhaps depositing ice-rich debris next to topographic obstacles.Future images of this region may provide clues, but for now this is a mystery.

Photo credit: NASA/JPL/University of Arizona

Note: This feature is located in Acidalia Planitia to the west of Cydonia Mensae, which is a short distance away.

Friday, May 3, 2013

Boulder Tracks in an Impact Crater South of Schiaparelli Crater


The original rationale behind this observation was to examine the slopes for changes since an earlier image in the same location. However, a feature that has NOT changed much since then still remains quite eye-catching. Multiple boulder tracks spill down the side of the crater.

When boulders roll down a dusty Martian slope, they can leave long, dotted tracks behind on the slope surface. Boulder tracks, like slope streaks, can be either brighter or darker than the surrounding terrain. The many boulder tracks in this image all seem to emanate from a small alcove near the rim of the crater. They spread out downslope and finally terminate near the crater floor. A high-contrast stretch of the area where the tracks stop shows lots of boulders, some still at the ends of the tracks.

HiRISE has seen boulder tracks fade over time in other locations. However, as compared to ESP_017975_1705 (taken in May of 2010), the tracks in this image (taken in March of 2013) don't seem to have faded as dramatically as that earlier example, despite a larger lapse in time between images. This might be because the crater in this image is in a less-dusty area of Mars.

Note: the above image has been rotated 90 degree counterclockwise for display purposes.

Photo credit: NASA/JPL/University of Arizona

Thursday, May 2, 2013

Gale Crater (2010) #21


During the month of April Mars will be in conjunction relative to the Earth. This means the Sun is in the line-of-sight between Earth and Mars, and communication between the two planets is almost impossible. For conjunction, the rovers and orbiting spacecraft at Mars continue to operate, but do not send the data to Earth. This recorded data will be sent to Earth when Mars moves away from the sun and the line-of-sight between Earth and Mars is reestablished. During conjunction the THEMIS image of the day will be a visual tour of Gale Crater, the location of the newest rover Curiosity.

The different features of the sand and sand dune field are readily visible in this image of the western floor of Gale Crater.

Orbit Number: 38546 Latitude: -4.98533 Longitude: 137.028 Instrument: VIS Captured: 2010-08-23 03:31

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

Note: This is the 21st in a series of images in which the THEMIS team is currently showing the central region of Gale Crater, starting at the eastern rim and moving past Mount Sharp to the western rim. Starting with image #9, the images are being shown from east to west. All of the images in this series I will name "Gale Crater (XXXX) #Y", in which XXXX is the year in which the photo was actually taken, and Y is the sequence number (1 through...).

Wednesday, May 1, 2013

Gale Crater (2003) #20


During the month of April Mars will be in conjunction relative to the Earth. This means the Sun is in the line-of-sight between Earth and Mars, and communication between the two planets is almost impossible. For conjunction, the rovers and orbiting spacecraft at Mars continue to operate, but do not send the data to Earth. This recorded data will be sent to Earth when Mars moves away from the sun and the line-of-sight between Earth and Mars is reestablished. During conjunction the THEMIS image of the day will be a visual tour of Gale Crater, the location of the newest rover Curiosity.

Showing the area just slightly west of the previous image, the large region of sand and sand dunes are the dark area that dominates this image.

Orbit Number: 5963 Latitude: -5.04024 Longitude: 137.098 Instrument: VIS Captured: 2003-04-19 09:41

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

Note: This is the twentieth in a series of images in which the THEMIS team is currently showing the central region of Gale Crater, starting at the eastern rim and moving past Mount Sharp to the western rim. Starting with image #9, the images are being shown from east to west. All of the images in this series I will name "Gale Crater (XXXX) #Y", in which XXXX is the year in which the photo was actually taken, and Y is the sequence number (1 through...).