Behind The Black – Robert Zimmerman

Click for full image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on May 29, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels an “unusual shaped hill” that is estimated to be about 20 to 40 feet high.

What makes it unusual? First, it sticks up out of the endless northern lowland plains for no obvious reason, though its shape suggests the existence of bedrock topography that is now buried by the dust and debris that coats the surface of those plains.

Second, the hill itself suggests that it formed after it was covered with debris. Note the crater near its northeast cliff. It appears that the cliff chopped off part of the crater, suggesting that the hill was once level with the surrounding terrain. Some later underground pressure pushed it upward, with its angled sides determined by existing faults.

Why those forces tilted the hill upward as it did, with only its eastern fringes raised, is a question a wide view might answer.
» Read more

Click for original image.

Cool image time! Only yesterday I posted an image of polygons in the dry equatorial regions of Mars, where little evidence of near-surface ice is found and are thought to be the remnants from a long-dried lakebed.

Today we take a look at some polygons in the mid-latitudes of the icy northern lowland plains, where near-surface ice appears ubiquitous and as it sublimates away with the changing seasons causes all kinds of strange formations, including polygons.

The picture to the right, cropped, reduced, and sharpened to post here, is a good example, centered on a 0.6-mile-wide bright crater that appears to be filled with glacial ice. The image was taken on June 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and is located at 44 degrees north latitude on the western edge of Utopia Basin. As noted by the MRO science team in 2006 for a different MRO picture with similar features:
» Read more

Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 26, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team calls the features surrounding these small 20 to 60 foot high hills “polygon features,” an apt description and a geological feature that is seen in many places on Mars.

When these features are found in the icy higher latitudes, it is believed they are formed in connection to the freeze-thaw cycle that causes cracks in the near surface ice. When found in the dry equatorial regions, where these polygons are located, they are usually thought to be ancient evidence of past standing water that left behind these cracks, much like the cracks seen in mud after the water has evaporated away on Earth.

The formation of these tiny hills is a bit more complex.
» Read more