jump to navigation

North Polar Layered Deposits in Head Scarp of Chasma Boreale January 9, 2010

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , , , ,
comments closed

North Polar Layered Deposits in Head Scarp of Chasma Boreale

Credit:

NASA/JPL/University of Arizona, Ken Herkenhoff

Description:

This false-color subimage shows the north polar layered deposits at top and darker materials at bottom exposed in a scarp at the head of Chasma Boreale, a large canyon eroded into the layered deposits.

The polar layered deposits appear red because of dust mixed within them, but are ice-rich as indicated by previous observations. The water ice in the layered deposits is probably responsible for the pattern of fractures seen near the top of the scarp.

The darker material below the layered deposits may have been deposited as sand dunes, as indicated by the cross-bedding (truncation of curved lines) seen near the middle of the scarp. It appears that brighter, ice-rich layers were deposited between the dark dunes in places.

Exposures such as these are useful in understanding the recent climate variations that are likely recorded in the polar layered deposits.

Wallpapers:

800×600
1024×768
1152×864
1280×960
1440×1080
1600×1200
1920×1440
2048×1536
2560×1600

Share:

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

Alluvial Fans in Mojave Crater: Did It Rain on Mars? January 8, 2010

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , , , , , ,
comments closed

Alluvial Fans in Mojave Crater: Did It Rain on Mars?

Credit:

NASA/JPL/University of Arizona, Alfred McEwen

Description:

Aptly-named Mojave Crater in the Xanthe Terra region has alluvial fans that look remarkably similar to landforms in the Mojave Desert of southeastern California and portions of Nevada and Arizona.

Alluvial fans are fan-shaped deposits of water-transported material (alluvium). They typically form at the base of hills or mountains where there is a marked break, or flattening of slope.

They typically deposit big rocks near their mouths (close to the mountains) and smaller rocks at greater distances. Alluvial fans form as a result of heavy desert downpours, typically thundershowers. Because deserts are poorly vegetated, heavy and short-lived downpours create a great deal of erosion and nearby deposition.

There are fans inside and around the outsides of Mojave crater on Mars that perfectly match the morphology of alluvial fans on Earth, with the exception of a few small impact craters dotting this Martian landscape.

Channels begin at the apex of topographic ridges, consistent with precipitation as the source of water, rather than groundwater. This remarkable landscape was first discovered from Mars Orbital Camera images. Mars researchers have suggested that impact-induced atmospheric precipitation may have created these unique landscapes.

This HiRISE image at up to 29 cm/pixel scale supports the alluvial fan interpretation, in particular by showing that the sizes of the largest rocks decrease away from the mouths of the fans.

Wallpapers:

800×600
1024×768
1152×864
1280×960
1440×1080
1600×1200
1920×1440
2048×1536
2560×1600

Share:

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

Starburst Spider (ESP_011842_0980) March 25, 2009

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , ,
comments closed

Starburst Spider

Credit:

NASA/JPL/University of Arizona

Description:

Mars’ seasonal cap of carbon dioxide ice (dry ice) has eroded many beautiful terrains as it sublimates (goes directly from ice to vapor) every spring. In this region we see troughs that form a starburst pattern.

In other areas these radial troughs have been referred to as “spiders,” simply because of their shape. In this region the pattern looks more dendritic as channels branch out numerous times as they get further from the center. The troughs are believed to be formed by gas flowing beneath the seasonal ice to openings where the gas escapes, carrying along dust from the surface below. The dust falls to the surface of the ice in fan-shaped deposits.

Mars’ Moon Deimos March 12, 2009

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , , , ,
comments closed

Deimos
Additional Image

Full Size
1024 x 768
800 x 600

Description:

These color-enhanced views of Deimos, the smaller of the two moons of Mars, were taken on Feb. 21, 2009, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. Deimos is about 7.5 miles in diameter.

Deimos has a smooth surface due to a blanket of fragmental rock or regolith, except for the most recent impact craters. It is a dark, reddish object, very similar to Mars’ other moon, Phobos.

These Deimos images combine HiRISE exposures in near-infrared, red and blue-green wavelengths. In the enhanced color, subtle color variations are visible — redder in the smoothest areas and less red near the fresh impact craters and over ridges of topographic highs. The color variations are probably caused by exposure of surface material to the space environment, which leads to darkening and reddening. Brighter and less-red surface materials have seen less exposure to space due to recent impacts or downslope movement of regolith.

Image Credit:

NASA/JPL-Caltech/University of Arizona

Layering in Uzer Crater Wall October 18, 2008

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , , , , ,
comments closed

Layering in Uzer Crater Wall

Credit:

NASA/JPL/University of Arizona

Description:

This image shows a portion of Uzer Crater, located in Sinus Meridiani near the equator in the northern hemisphere of Mars.

Light-toned layered rocks are visible on the wall of Uzer Crater. Differences in color highlight variations in the layered units. Wind erosion, in particular, has modified the layers since exposure creating rounded depressions. These layers are interpreted to be an outcrop of sedimentary rocks that formed by sediments once deposited in this area. The origin of the sediments composing the layers is unknown but may have included fluvial processes and wind blown particles such as dust or volcanic ash.

Over time, the sediments were solidified into rock and eventually exposed when an impact formed Uzer Crater. Northern Sinus Meridiani has many similar outcrops of light-toned sedimentary material that are observed over a large region.

On Mars, as on Earth, sedimentary rocks preserve a record of past environments. HiRISE color images reveal details in the layers that will help scientists learn more about their origin.

Wallpapers:

800×600
1024×768
1152×864
1280×960
1440×1080
1600×1200
1920×1440
2048×1536
2560×1600

Crater on North Polar Layered Deposits October 16, 2008

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , , ,
comments closed

Crater on North Polar Layered Deposits

Credit:

NASA/JPL/University of Arizona

Description:

The north polar layered deposits, and the bright ice cap that covers them, are very young (by geologic standards) features. To try and figure out the age of an area, or how quickly it’s being resurfaced, planetary scientists count up the number of craters at different sizes. An older surface has more time to accumulate more craters whereas a younger surface, or one that has a lot of geologic activity that destroys craters, doesn’t have many impact craters.

These polar deposits have a very low crater count so it is possible that the ice cap (bright white in this image) might only by about 10,000 years old and the surface of the layered deposits (orange-brown in this image) may be only a few million years old. This sounds like a long time but is very short compared to other surfaces on Mars.

HiRISE is enabling a more detailed study of these polar craters and the target of this observation is visible in the center of the image. This crater proved to be a surprise in a few ways. Its shape is non-circular which is quite unusual for an impact crater. One possibility is that flow of the ice beneath the surrounding terrain has deformed the crater; however, ice-flow rates are thought to be very low on Mars today.

The crater also contains a patch of bright ice despite being surrounded by terrain that has mostly lost its ice cover. This seems typical for these polar craters and it may be that ice within these craters is protected from ablation by shading from the crater walls.

Wallpaper:

800×600
1024×768
1152×864
1280×960
1440×1080
1600×1200
1920×1440
2048×1536
2560×1600

Saltating Gypsum into Dark Polar Dunes October 16, 2008

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , , , , , ,
comments closed

Saltating Gypsum into Dark Polar Dunes

Credit:

NASA/JPL/University of Arizona

Description:

Gypsum is a common water-based mineral found in evaporative beds (ancient lakes or seas) on Earth. Gypsum rarely occurs in sand dunes on Earth as it is water-soluble (dissolves in water). However, gypsum can be trapped in basins that have no water outlets or receive very light precipitation and form beautiful dunes. The White Sands National Monument in the Tularosa Basin, New Mexico, is the largest gypsum dune field in the world. OMEGA, an instrument onboard the European Space Agency’s (ESA) Mars Express has detected gypsum deposits in the Martian north polar erg.

Where did the gypsum come from? Scientists propose that gypsum deposits formed as a result of melting or retreating ice sheets in a polar evaporate basal unit. In this image, gypsum may originate from the bright bedrock and may mix with saltating dark sand. However, the true source of the gypsum is still debated among planetary scientists.

The mafic (basaltic) dark dunes are predominately transverse with transitioning linear and barchanoid dunes with the wind coming from changing west-northwest and west-southwest directions. These dunes have several active processes occurring within them; grain avalanching is present at the crest of dunes and fading dark slope streaks are visible on the slipface.

Additional Images:

Full image (grayscale, map projected)

Full image (grayscale, non-map projected)

IRB color (map projected)

IRB color (non-map projected)

RGB color (non-map projected)

Translucent Ice in North Polar Region October 12, 2008

Posted by John Tintle (MtO deadbait) in Space Fotos.
Tags: , , , , ,
comments closed

 Translucent Ice in North Polar Region

Credit:

NASA/JPL/University of Arizona

Description:

This polar terrain is located near the north pole. The bright patch of material is ice, which might have been deposited in the previous winter.

After ice in the form of surface frost is deposited from the atmosphere, it experiences changes throughout the Martian year. Some of the ice has a polygonal texture which probably formed when temperature variations created stress and cracks in the ice.

The dark features scattered throughout the scene are dunes. The streaks emanating from the dunes trending in the southwest direction indicate the dominant direction of the wind in recent times

Additional Images:

Full image (grayscale, map projected)

Full image (grayscale, non-map projected)

IRB color (map projected)

IRB color (non-map projected)

RGB color (non-map projected)

Layers of Red Cliffs on Mars October 12, 2008

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , , , , ,
comments closed

See Explanation.  Clicking on the picture will download  the highest resolution version available.

Credit:

HiRISE, MRO, LPL (U. Arizona), NASA

Explanation:

How did these layers of red cliffs form on Mars? No one is sure. The northern ice cap on Mars is nearly divided into two by a huge division named Chasma Boreale. No similar formation occurs on Earth. Pictured above, several dusty layers leading into this deep chasm are visible. Cliff faces, mostly facing left but still partly visible from above, appear dramatically red. The light areas are likely water ice. The above image spans about one kilometer near the north of Mars, and the elevation drop from right to left is over a kilometer. One hypothesis relates the formation of Chasma Boreale to underlying volcanic activity.

Dark Spot Near Olmpus Mons Volcano September 24, 2008

Posted by John Tintle (MtO deadbait) in Planets, Space Fotos.
Tags: , , , , ,
comments closed

Dark Spot Near Olmpus Mons Volcano

Credit:

NASA/JPL/University of Arizona

Wallpaper:

800×600
1024×768
1152×864
1280×960
1440×1080
1600×1200
1920×1440
2048×1536
2560×1600

Description:

This image covers a relatively dark-toned patch of ground west of the Olympus Mons volcano. This spot is one of several dark areas in this region of Mars.

These dark spots are distinctive because much of the surrounding area appears to be covered by light-toned dust. In pre-HiRISE images, the origin of this dark spot was ambiguous. This HiRISE image reveals that the dark color is likely the result of accumulations of basaltic sand (smooth, blue-colored material in the color swath) on top of otherwise relatively dust-free bedrock.

Evidence of layering is also visible within the dark (blue) area. There are alternating bands of lighter- and darker-toned material, consistent with alternating layers of bedrock. These alternating bands are not apparent outside of the dark area. This may mean that alternating layers of bedrock only occur within the dark area, or that these bedrock layers occur throughout the region but are covered and obscured by light-toned dust outside of the dark area

Follow

Get every new post delivered to your Inbox.

Join 229 other followers

%d bloggers like this: