Posts Tagged ‘HiRISE’

Martian Pie Shell

Credit: NASA/JPL/University of Arizona

Gullies and debris litter the bottom of this Martian crater making it resemble a pie shell that has been dropped.

Explore this image from NASA’s HiRISE camera aboard the Mars Reconnaissance Orbiter of a small crater. What other shapes and stories does your imagination see in this image? Leave a note below.

While there is no substantial surface water on Mars to create gullies, wind and debris flows can create similar features. These gullies are found on the pole facing slopes. Perhaps freezing and thawing action has caused much debris from the rims to flow to the crater floor. Geologists theorize that some of the snaky ridges on the crater floor could be moraines. Moraines are places where boulders, stones, sand and dirt accumulate after being bulldozed by other processes. On Earth, moraines are usually associated with glaciers. On Mars, however, this debris could pile up as other rock and sand accumulate behind them.

As you explore the crater, look for dunes in the bottom of the crater along the edges. They create right angles with the crater edge as if the wind swirls in the bottom of the crater. Can you pick out other dunes inside the crater?

This small crater is part of a larger crater known as Newton Crater. Named after Sir Isaac Newton, Newton Crater is about 300 kilometers (or 186 miles) in diameter. It sits in the heavily cratered highlands of Terra Sirenum in the southern hemisphere of Mars. A low area in the highlands is believed to have once contained a lake that eventually drained and dried up.

Launched with Mars Recon­nais­sance Orbiter, or MRO, in 2005, HiRISE is one of six instru­ments aboard the space­craft orbit­ing Mars. HiRISEs cam­era can see objects on the sur­face as small as a beach ball. The instru­ment can also offer sci­en­tists stereo views of the surface.

Rough hide of Mars

Credit: NASA/JPL/University of Arizona

From orbit, some landscapes of Mars resemble a rough animal hide. Explore this image from the HiRISE camera aboard Mars Reconnaissance Orbiter and you can find just about every type of sand dune known to exist. What shapes and stories can your imagination dream up from this image? Share a note below.

Scientists call the dunes in the center of this image parabolic dunes. On Earth, parabolic dunes are created where some vegetation holds part of the dune edge in place. There is no plants or vegetation on Mars to hold the sand and dust. In the hollow of this crater, shifting winds likely push sand in all directions resulting in these dunes. Travel to the upper right part of the image and explore the linear and crescent dunes. In the plains in the upper left of the image, you can find longitudinal dunes. These dunes extend for long distances and become longer with the wind. As you pass across the mountainous landscape, look for outcrops that form the center of a dune pinwheel. Sometimes wind currents swirl around these hills creating the sand dunes.

The crater central to this image is special in itself. Planetary geologists call it a central pit crater. Scientists do not know exactly how they form but they could be created when gases escape from the central peak after a meteorite impact causing the peak to collapse.

Launched with Mars Recon­nais­sance Orbiter, or MRO, in 2005, HiRISE is one of six instru­ments aboard the space­craft orbit­ing Mars. HiRISEs cam­era can see objects on the sur­face as small as a beach ball. The instru­ment can also offer sci­en­tists stereo views of the surface.

X Marks the Spot

Credit: NASA/JPL/University of Arizona

“X” marks the spot in this image of wind-blown dunes in Argyre Planitia from NASA’s HiRISE camera.

Explore the hills and dune fields of this plain within the huge Argyre impact basin. What shapes and stories does your imagination create? Share your stories below. Wind, sand and dust play a huge role in shaping the surface in the Martian highlands. Broad expanses of sand dunes, driven by prevailing winds blowing in a northwesterly direction, dominate the shallow valleys in this image. These types of sand dunes are called transverse dunes. They are driven by constant winds blowing consistently from a certain direction. The most prominent feature in this image is the “X” along the large dune in the middle of the image. This dune is a bit different than others in the image. It is long and narrow, flowing with the direction of the wind. Scientists call these longitudinal dunes.

The “X” and other dark marks especially near the top of the image show the paths of dust devils. Dust dev­ils occur on Earth too. These strong, well-formed whirl­winds are like mini-tornadoes. They are ver­ti­cally rotat­ing columns of air formed when warm air at the sur­face punches through cooler air above. The col­umn of air may begin to rotate. When it does, more warm air is sucked in from the sur­round­ing area giv­ing it more power. The sur­round­ing cooler air con­tains the spin­ning col­umn of warm. On Mars, spin­ning dust dev­ils pick up the fine dust leav­ing darker sand behind show­ing the swirling paths. Sand and dust also fill in craters and other shallow areas throughout this image.

Argyre Planitia is a plain located within the huge impact basin in the southern highlands of Mars. The basin is about 1,120 miles across (1,800 km) and is believed to be the second largest impact basin on Mars. The center of Argyre drops 3.2 miles (5.2 km) below the surrounding plains. The basin is visible from Earth and was first mapped by Giovanni Schiaparelli in 1877. He named the feature after the mythical island of silver in Greek mythology.

Dragons of Mars

Credit: NASA/JPL/University of Arizona

A dragon, tongue flicking out, struts along this rocky landscape on Mars in this image from NASA’s HiRISE camera aboard the Mars Reconnaissance Orbiter.

Explore this image of this terrain dominated with rocky hills and sand dunes within Holden Crater. Share other shapes and stories you see in this image by leaving a note below.

Holden Crater, in the tropics of Mars, is one of several landing sites scientists are considering for the Curiosity mission. The car-sized rover, a big brother to the Spirit and Opportunity rovers, will roam the surface analyzing and gathering samples and taking photos along the way. The image shows some of the reasons why scientists are interested in sending Curiosity to Holden Crater. Look for light-toned layered rock covered by the darker, windblown dunes. The layers may have been deposited by ancient lakes. Perhaps these lakes were home to ancient life on Mars. If we could zoom out to see all of Holden Crater, scientists think they see evidence for massive flooding. The flooding would have rearranged boulders, bringing new material to the surface.

Launched with Mars Recon­nais­sance Orbiter, or MRO, in 2005, HiRISE is one of six instru­ments aboard the space­craft orbit­ing Mars. HiRISEs cam­era can see objects on the sur­face as small as a beach ball. The instru­ment can also offer sci­en­tists stereo views of the sur­face.

A thousand Martian spiders

Credit: NASA/JPL/University of Arizona

Martian spiders scurry around the surface in this image from NASA’s HiRISE camera.

Explore the spidery terrain image. What stories or pictures do you see? Leave a note below.

In reality, no spiders are found on Mars. This lacy terrain is unlike anything we see on Earth.These striking, and a bit scary, patterns, may be caused by freezing and thawing action on Mars. As carbon dioxide ice is heated by the Sun it goes directly to a gas in a process called sublimation. Scientists speculate that gas flows along these channels until it encounters a vent. The gas escapes scattering dust that is carried along. Scientists call this type of terrain “araneiform,” or “spider-like”.

Launched with Mars Reconnaissance Orbiter, or MRO, in 2005, HiRISE is one of six instru­ments aboard the space­craft orbit­ing Mars. HiRISEs cam­era can see objects on the sur­face as small as a beach ball. The instru­ment can also offer sci­en­tists stereo views of the sur­face. When com­bined with dig­i­tal ter­rain mod­els, sci­en­tists can “drape” the imagery to pro­duce real­is­tic land­scapes to study and explore.

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The ancient peoples saw pictures in the sky. From those patterns in the heavens, ancient storytellers created legends about heroes, maidens, dragons, bears, centaurs, dogs and mythical creatures...
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