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My February birthday fund-raising campaign for Behind the Black is now over. Thank you to everyone that so generously donated. You don’t have to give anything to read my work, and yet so many of you donate or subscribe. I can’t express what that support means to me.

 

For those who still wish to support my work, please consider donating or subscribing to Behind the Black, either by giving a one-time contribution or a regular subscription. There are five ways of doing so:

 

1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.

 

2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation. Takes about a 10% cut.

 

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4. Donate by check. I get whatever you donate. Make the check payable to Robert Zimmerman and mail it to

 
Behind The Black
c/o Robert Zimmerman
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You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.


Layers in the biggest canyon in the solar system

Overview map

Layers in the solar system's biggest canyon
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 24, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The white dot on the overview map above marks the location, on the lower slopes of the south rim of Valles Marineris, the largest canyon on Mars and by far the largest so far discovered in the solar system. From the rim to the floor the elevation drop here is about 23,000 feet, with the layers shown in the picture to be about 5,000 feet above the canyon floor.

Those layers cover about 500 feet of that elevation drop. Each layer suggests a past event, possibly volcanic eruptions. The curved headwall near the upper left also suggests that some layers were avalanches or mass wasting events flowing downhill to the northeast, one on top of another.

As always, the scale of Valles Marineris is hard to imagine. The rim is 20 miles to the south, but the canyon’s opposite rim is from 140 to 300 miles to the north. You could fit two to five Grand Canyons in this part of Valles Marineris and each would look small in comparison.

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 or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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

One comment

  • I am wondering how long some of Mars’ given names will last, once people have to use them. There aren’t any indigenous cultures around to reinforce place names.

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