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Readers!

 

It is now July, time once again to celebrate the start of this webpage in 2010 with my annual July fund-raising campaign.

 

This year I celebrate the fifteenth anniversary since I began Behind the Black. During that time I have done more than 33,000 posts, mostly covering the global space industry and the related planetary and astronomical science that comes from it. Along the way I have also felt compelled as a free American citizen to regularly post my thoughts on the politics and culture of the time, partly because I think it is important for free Americans to do so, and partly because those politics and that culture have a direct impact on the future of our civilization and its on-going efforts to explore and eventually colonize the solar system.

 

You can’t understand one without understanding the other.

 

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Mysterious dark-toned Martian terrain

Dark toned ridge in Martian southern highlands
Click for full resolution image

Cool image time! The picture on the right, cropped and reduced to post here, was part of the January image release from the high resolution camera of Mars Reconnaissance Orbiter (MRO). It shows an area in the Martian southern highlands where the surface suddenly gets darker, for no obvious reason.

The uncaptioned release image is titled “Dark-Toned Ridge at Junction with Dark-Toned Plain.” From the image itself it is hard to understand this title. In the full image the darkest terrain is a strip in the center, with slightly lighter dark terrain on either side, and the lightest terrain to the north or south. The photograph however does not show us how far this dark terrain extends to the west or east.

Two Mars Odyssey image strips of less resolution, here and here, show that this region is filled with several large patches of dark-tone surface. With this particular patch the center dark ridge is surrounded by that slightly lighter dark area.

MRO itself has not taken many images of this region, as shown in the overview image below. The red rectangles indicate MRO’s high resolution photographs, with this image indicated by the cross. At this low resolution this region seems somewhat nondescript. The Mars Odyssey image strips show that there many features here, but with little significant relief.

Location of dark toned ridge

At high resolution there does not appear to be much difference between the darker and lighter areas. The lighter areas in general seem less rough and at a slightly lower elevation, but both areas are dominated by ridges and dunes trending southwest-to-northeast.

Why is this slightly higher region darker? Let’s assume that this darker material was a lava flow overlaying the surface. Over eons wind erosion, trending southwest-to-northwest, roughly eroded both it and the lower layers around it, leaving behind this rough corroded terrain. The different make-up of the darker material allows it to erode in a rougher manner.

While possibly correct, I would not bet much money on this guess. It is not clear it is lava. It is not clear that it is a flow. It does not explain why there are two areas of different darkness. And it certainly not clear what the make-up of any of this stuff is.

This is simply another cool mystery on the Martian surface.

Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

 

The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.


The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
 

"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News

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