Of Ergs, Noses and Flocks of Birds

Credit: NASA/JPL/University of Arizona

The transition from winter to spring on Mars must be an interesting time. As the sun rises higher in the sky and temperatures rise from extreme cold to bitter cold, geysers of carbon dioxide begin to erupt in geysers and cracks of escaping gas.

Explore this Martian terrain known as the North Polar Erg from NASA’s HiRISE camera aboard the Mars Reconnaissance Orbiter. Can you see various face shapes, birds and animals? What shapes or stories do you see in the image? Leave a note below.

During the harsh winter, carbon dioxide condenses onto the surface forming polar caps. As the landscape warms, this carbon dioxide goes straight from solid to gas in a process scientists call sublimation. When the gas bursts through the surface, it brings up dark-colored sand. On Earth, most sand is made up of light-colored quartz, or silica, sand. On Mars, the sand is made up of a dark mineral called basalt similar to the black sand beaches of Hawaii. A layer of reddish iron oxide dust coats the barchan dunes in this image. Where there are cracks in the ice, dark sand is seen coming to the surface. Some cracks are at the tops of the dunes and the sand slides down the dune face. Other areas feature geyser like holes where sand is shot up into the air and falls down in a bulls-eye pattern surrounding the hole or if the wind is blowing, the sand creates a fan-shaped feature.

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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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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