More caves on Mars

For many reasons, mostly political but partly ethical, I do not use Google, Facebook, Twitter. They practice corrupt business policies, while targeting conservative websites for censoring, facts repeatedly confirmed by news stories and by my sense that Facebook has taken action to prevent my readers from recommending Behind the Black to their friends.
Thus, I must have your direct support to keep this webpage alive. Not only does the money pay the bills, it gives me the freedom to speak honestly about science and culture, instead of being forced to write it as others demand.


Please consider donating by giving either a one-time contribution or a regular subscription, as outlined in the tip jar below.


Regular readers can support Behind The Black with a contribution via paypal:

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

If Paypal doesn'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


You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage. And if you buy the books through the ebookit links, I get a larger cut and I get it sooner.

And damn, do I want to rappel into them!

This week’s release of images from the HiRISE camera on Mars Reconnaissance Orbiter included these spectacular photos of two deep pits, approximately 180 and 310 meters in diameter and located aligned with a series of depressions that suggest additional passages at their base.

The first image shows the pits in the context of the surrounding terrain. From the caption:

These pits are aligned with what appears to be larger, degraded depressions. The wispy deposit may consist of dark material that has been either blown out of the pits or from some other source and scattered about by the local winds.

wide shot of pits

The next two images are heavily processed close-ups of each pit in order to bring out the detail within. From the caption:

The eastern most and smaller of the two pits contains boulders and sediment along its walls and brighter aeolian dune sediments on its floor. The larger, western most pit contains sediment and boulders with faint dune-like patterns visible on the deepest part of the floor. Both pits have steep eastern walls and more gently sloped western walls that transition gradually into the pit floor. Steep resistant ledges containing boulders that overhang and obscure the pit floors form the eastern walls.

The smaller pit, with dunes on floor

The larger pit



  • Cheryl Suitor

    Too bad these pits are a five year drive, one way, or I’d “get a rope”!
    Thanks for posting these pictures…very interesting.

  • Dave Hollick

    These look surprisingly similiar to pits I’ve dropped here on Earth. I’m curious how rappelling would be in reduced gravity.

  • Bob Chiasson

    Now NASA needs to develop/modify a Mars helicopter to enter and map the pits. Perhaps there is some way that later missions could cover one with a dome and seal it for use as a habitat.

Leave a Reply

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