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My July fund-raising campaign, celebrating the 13th anniversary of the start of this website, has now ended. This was the second most successful monthly fund-raising campaign ever. Thank you again to everyone who has who donated or subscribed. It is difficult to explain what your support means to me.


You can still donate or subscribe to support my work if you wish, either by giving a one-time contribution or a regular subscription. There are four 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.

3. A Paypal Donation:

4. A Paypal subscription:

5. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652

Martian terraces

Overview map
Glacier country on Mars

Martian terraces
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on May 17, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists have labeled “Dipping layers against mound in Deuteronilus Mensae.”

Deuteronilus is the westernmost mensae region in the 2,000-mile-long strip of heavy glaciers found in the northern mid-latitudes that I dub glacier country. This photo, the location of which is marked by the white cross on the overview map above, is another example, though somewhat strange and puzzling. Normally the layers will dip away from the high point. Here, the layers dip towards the mound. I can think of only one explanation, that of prevailing winds causing the erosion in this unusual manner, but I also find that explanation very unsatisfactory.

The layers themselves illustrate the cycles that have shaped Martian geology, caused by the wide swings in the planet’s rotational tilt, from 11 to 60 degrees. When that tilt is high, the poles are warmer than the mid-latitudes, and water ice migrates from the poles towards the equator. When the tilt is low, the mid-latitudes are warmer, and the water ice heads back towards the poles. Thus, the many many layers the orbiters and rovers are now finding everywhere on Mars.

Right now scientists think, because Mars’ tilt is in the middle of these swings at 25 degrees, the planet is in equilibrium, with the water at the poles and mid-latitudes essentially going no where. This conclusion however is not yet confirmed.

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 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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