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I am now in the third week of my annual February birthday fund-raising drive. The first two weeks were good, but not record-setting.


There are still two weeks left in this campaign however. If you have been a regular reader and a fan of my work and have not yet donated or subscribed, please consider doing so. I take no ads, I keep the website clean from pop-ups and annoying demands (most of the time). Thus, I depend entirely on my readers to support me. Though this means I am sacrificing some income, it also means that I remain entirely independent from outside pressure. By depending solely on donations and subscriptions from my readers, no one can threaten me with censorship. You don't like what I write, you can simply go elsewhere.


You can support me 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.

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

Cracked ash-filled Martian terrain

Cracked ash-filled fissures on Mars
Click for original image.

Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken on September 26, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team labeled this “Possible Pit,” but other than a small dark stain on the rim of a crater north of the section cropped to the right, I could find nothing that even closely resembled a pit. More likely the scientists were referring to the large circular depression in the top center of this picture. It does not at first glance look like a crater, as it has no obvious rim. In fact, almost none of the circular depressions in this image look like craters, as almost none have uplifted rims.

However, it is not clear what caused these dust-filled fractures as well as the image’s many circular depressions. The location, as indicated by the overview map below, does not really help.

Overview map

The small red dot, south of Cerberus Fossae and inside the Medusae Fossae Formation, Mars’s biggest deposit of volcanic ash, marks the location of these cracks. Though this is very close to one of the large quakes detected by InSight, these cracks are much much older.

Because this is near the equator, there is no near surface ice here. This is very dry terrain. Being inside Medusae Fossae explains the amount of ash filling the fissures and pits. In fact, it could be we are seeing chaos terrain whose intersecting canyons are almost entirely filled with that ash.

Or not. Maybe the ash is so thick here that impacts don’t form rims, but disappear into the ash like a hot pebble falling into ice.

This is also in a region of many vast flood lava plains. The surface here is likely lava, but why it has these cracks and fissures is beyond my status as an amateur geologist to explain.

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

One comment

  • Max

    “The science team labeled this “Possible Pit,” but other than a small dark stain on the rim of a crater north of the section cropped to the right, I could find nothing that even closely resembled a pit”

    Look for a white stain.
    On your original link, there are some dark holes near what looks like white ejecta. Something new…

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