Posts Tagged ‘HiRISE’

Ripples and Shadows

NASA/JPL/University of Arizona

Ripples, dunes and shadows create swirling and looping patterns in this image from the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter.

Explore the sprawling Martian dunefield. What stories and patterns do you see? Leave a note in the comments below.

Scientists use images like this one to not only study wind processes on Mars but also to look for fresh impact craters. From time to time, HiRISE takes images of the same part of the Red Planet giving scientists a chance to see what has changed between images. Scientists are not sure whether Martian dunes have evolved over thousands of years or if they are young features. Dunes in this image appear fresh and young. They have sharp crestlines (top of dunes) and active looking slipfaces (downwind slopes of dunes). Most of the dunes point toward the southwest which shows the predominant wind direction in this area. But some dunes show signs of sand being pushed back up the slope making the slopes smooth with few ripples. A quick look around the image shows that no impact craters are present. More dune fields are left to explore.

Launched with MRO in 2005, HiRISE is one of six instru­ments aboard the space­craft orbit­ing Mars. HiRISE’s cam­eras can see objects on the sur­face as small as a beach ball. The cam­era also offers sci­en­tists stereo views of the surface.

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Just a Boulder

NASA/JPL/University of Arizona

Rocks and waves of sand dominate this image of Mars from the HiRISE camera. However, some find an mysterious rectangular-shaped boulder sticking out of a hillside.

Explore the rugged terrain of Mars starting in the area of the enigmatic, rectangular boulder. What shapes and stories do you see in the sands of Mars? Leave a note below.

If you look around the boulder-field at the bottom of this hillside, you’ll find lots of shadows that are rectangular looking. But are they all “monoliths” placed by aliens similar to those created by Arthur C. Clarke in his story “The Sentinel” and popularized in the Stanley Kubrick film “2001: A Space Odyssey?” The answer lies probably in the play between shadows and image resolution. Pixels on images are square. If you look really close at the monitor you are using you’ll find a rectangular grid of glowing square pixels make up the text and images on this screen. The HiRISE camera has a resolution of about 30 centimeters. That means that one pixel equals about 30 centimeters or about one foot. That’s only about the size of a beach ball. Big boulders become square-like objects; shadows become square-like as well. An early morning or late afternoon sun creates long shadows making objects appear larger than they really are. Very similar to walking down a road with your back to the Sun at sunset and seeing your shadow stretch out tens of feet in front of you.

You can read more about this effect in a post at Life’s Little Mysteries.

The more interesting stuff in this image are the ripples of sand that drift across the plateau craters and then march along the bottom of the canyon at the bottom of the image. Sand has nearly filled in the double craters in the center of the image creating a pie-shape. Geologists find this image interesting because of the layers of rock that make up the wall of the canyon.

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

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Sandy Tuning Forks

Credit: NASA/JPL/University of Arizona

Tuning forks on tuning forks cross Mars in this image from HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter.

Explore the snaking dunes in this image. What stories or pictures does your imagination make in the shifting sands of Mars? Leave a note below.

Wind is a main force on Mars stirring up dust devils and sometimes global dust storms. Typically, wind on Mars creates fascinating dune fields. Many types of dunes are seen in this image from the mid latitudes of Mars. The long ridges of sand are called linear dunes. On Earth, these dunes can extend for more than a hundred kilometers. They form when the wind blows from two directions. In this image, the wind seems to blow from bottom to top and from the side. As time passes, these dunes will move slowly along the surface acting like a snake as they move. Some dunes merge to form Y-shaped dunes; the tuning forks we see in the image.

As you zoom into the dunes, look for star-shaped dunes, crescent-shaped dunes and smaller ripples on the larger dunes. In the lower left-hand corner of the image, look for a crater that is nearly filled with sand and dunes.

Launched with MRO in 2005, HiRISE is one of six instruments aboard the spacecraft orbiting Mars. HiRISE’s cameras can see objects on the surface as small as a beach ball. The camera also offers scientists stereo views of the surface.

Lines in the Sand

Credit: NASA/JPL/University of Arizona

Swirls in the dust mark out lines in the sand where dust devils play along the ridges in the high latitudes of Mars in this image from NASA’s HiRISE camera.

Explore the hills, gullies and dune fields within this image. What shapes and sto­ries does your imag­i­na­tion cre­ate? Share your sto­ries below.

Wind, sand and dust play a huge role in shap­ing the sur­face of Mars. The dark swirls dominating this landscape 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.

Streaking on Mars

Credit: NASA/JPL/University of Arizona

Streaks along a crater rim on Mars take on a wavy and ghostly appearance in this image form NASA’s HiRISE camera.

What stories does your imagination create with the shapes and patterns found in this image? leave a note below.

Explore the crater and surrounding plains. Unlike the light-colored sand abundant on the beaches of Earth, Martian sand is dark and made up mostly of a dark mineral called basalt. On Mars, lightly colored windblown dust covers most of surface. But when the surface is disturbed by dust devils or landslides, the dark sand is exposed leaving striking patterns.

As you move away from what scientists call slope streaks, look for the channel cut into the crater wall and floor. At one time in Mars‘ distant past, lava surrounded the crater, found a low part in the rim and channeled its way to the bottom. This must have happened on an early Mars. Look for fresh and eroded craters in the plains above the crater.

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.

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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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