Pioneer cover

From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.

Unfortunately, that is exactly where that journey takes him.

The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.

He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.

Available everywhere for $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from the ebook publisher, ebookit. And if you buy it from ebookit you don't support the big tech companies and I get a bigger cut much sooner.

Cracks, chaos, and maybe caves in one place on Mars

Mosaic of Avernus Cavi fissures
Click for higher resolution. Original images found here and here.

Today’s cool image to the right is a mosaic I have made from two images taken by the context camera on Mars Reconnaissance Orbiter (MRO), showing a most intriguing region on Mars dubbed Avernus Cavi, located in the large volcanic plain called Elysium Planitia between the giant volcanoes Elysium Mons and Olympus Mons, a region I like to call Mars’ volcano country.

The mosaic shows in one picture much of the typical terrain in Avernus Cavi. We see many linear depressions or cracks, created when the ground stretched and cracked at weak points. We also see many depressions that suggest sinkholes, places where the surface sagged down because of a void below ground.

The area of knobs and mesas in the picture’s southeast quadrant is very typical Martian chaos terrain, the later result of long term erosion of these cracks and depressions.

The white box shows the area covered by the image below.

Closeup of fissures
Click for full image.

The photo, cropped and reduced to post here, covers a section of a March 2020 MRO high resolution picture of these cracks, posted today as that camera’s picture of the day. The short caption:

This image features small collection of cave candidates in Avernus Cavi, located in Elysium Planitia. These candidates are located at the base of scarps formed by extensional fracturing. We might be able to resolve rim and floor textures as finely as possible to verify if any caves are indeed present.

In other words, no cave entrances have as yet been identified, but scientists are taking high resolution images in an effort to find them. The assumption is that the cracks and fractures are much deeper than what we can see on the surface, and that there are likely voids below.

The black rectangle in the mosaic above shows the area covered by another MRO high resolution image, taken in 2015 and labeled “Lines of Pits in Avernus Cavi Region.” What struck me about that image was how much the depressions appear to reflect a river tributary system. This is not we are looking at, but that’s what it invokes. Like the first picture above, the cracks occur because the land has become stretched, opening up fissures along fault lines.

Overview map

As shown by the red cross in the overview map to the right, Avernus Cavi is located within the huge volcanic ash deposit called the Medusa Fossae Formation, thought to be the source of most of Mars’ dust. This is also at the Martian equator, so the surface in this region is very dry, with most features the result of some volcanic process.

It is also relatively close to the majority of the quakes detected by InSight, suggesting that such cracks and fissures could still be spreading and shifting.


I must unfortunately ask you for your financial support because I do not depend on ads and rely entirely on the generosity of readers to keep Behind the Black running. You can either make a one time donation for whatever amount you wish, or you sign up for a monthly subscription ranging from $2 to $15 through Paypal or $3 to $50 through Patreon.

Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.

Your support is even more essential to me because I not only keep this site free from advertisements, I do not use the corrupt social media companies like Google, Twitter, and Facebook to promote my work. I depend wholly on the direct support of my readers.

You can provide that support to Behind The Black with a contribution via Patreon or PayPal. To use Patreon, go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation. For PayPal click one of the following buttons:


Or with a subscription with regular donations from your Paypal or credit card account:


If Patreon or Paypal don't work for you, you can support Behind The Black directly by sending your donation by check, payable to Robert Zimmerman, to

Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652

Or you can donate by using Zelle through your bank. You will need to give my name and email address (found at the bottom of the "About" page). The best part of this electronic option is that no fees will be deducted! What you donate will be what I receive.


  • I hardly ever comment on them because I have nothing to add, but these Mars pictures and explanations are the biggest reason I visit this site. Just so you know.

  • markedup2: Thank you. I often wonder if there really is a lot of interest in these cool images, as the number of comments are always far less than the political posts.

    Not that it matters. Everything I do on BtB is because it is something that interests me. Which means I will keep posting them, because I enjoy it and doing so gives me some relief from the truly depressing news of the day.

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 *