Scroll down to read this post.


Please consider supporting my work, as I take no advertisements nor accept any sponsors in order to keep the website clean, easy to read, and to avoid any accusations of conflict of interest. Your support leaves me entirely independent, able to say whatever I think while being free from censorship or reprisals.


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

A Martian glacier waterfall?

A Martian glacier waterfall?
Click for original image.

Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken on October 25, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small meandering canyon that appears to drain into a larger side canyon, all part of a region of chaos terrain dubbed Galaxias Chaos in the Martian northern mid-latitudes.

Though the latitude is 35 degrees north, where we should see lots of evidence of glacial features, especially because this is chaos terrain — terrain unique to Mars — that generally appears formed by such processes, I find few outright obvious glacial features in this cropped portion or in the full image.

Overview map

The white dot north of the shield volcano Elysium Mons marks the location of this picture. Once again, at this latitude it is pretty routine to find glacial features. It is likely that even though nothing in this picture is obviously glacial, the ground here is permeated with ice, which when it sublimates away leaves behind the stippled surfaces. Furthermore, the channel heading downhill from the top center and along the base of the cliff sure seems to be a typical Martian glacial flow, though not plainly so.

Regardless, this small channel, which scientists for decades have assumed was formed — like all of Mars channels — by flowing liquid water, could very well have been carved by the ubiquitous glaciers on Mars. If so, that glacier became a glacial waterfall when it reached the cliff, and then continued downhill to the north, as seen by the faint channel cutting through the ridges below the plateau.

Or not. It remains an unresolved question whether the channels of Mars were caused by water or ice.

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


Readers: the rules for commenting!


No registration is required. I welcome all opinions, even those that strongly criticize my commentary.


However, name-calling and obscenities will not be tolerated. First time offenders who are new to the site will be warned. Second time offenders or first time offenders who have been here awhile will be suspended for a week. After that, I will ban you. Period.


Note also that first time commenters as well as any comment with more than one link will be placed in moderation for my approval. Be patient, I will get to it.

Leave a Reply

Your email address will not be published. Required fields are marked *