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I am now in the final week of my July fund-raising campaign for Behind the Black, celebrating its 14th anniversary. Thank you all, from the people who have donated small amounts to those who have given large sums. I cannot truly express how much your support means to me.


The support of my readers through the years has given me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Four years ago, just before the 2020 election I wrote that Joe Biden's mental health was suspect. Only in the past two weeks has the mainstream media decided to recognize that basic fact.


Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Even today NASA and Congress refuses to recognize this reality.


In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.


Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.


Please consider supporting my work here at Behind the Black.


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.


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Slope streaks in frozen lava flows on Mars

Slope streaks on frozen lava
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on June 5, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a ridgeline at the base of the giant volcano Pavonis Mons, with slope streaks on ridge’s north and south sides.

Slope streaks are a mysterious phenomenon unique to Mars. While they resemble an avalanche, they do not change the topography of the surface at all. They appear to occur randomly year round, fading slowly with time. Also, while most are dark, scientists have also spotted bright slope streaks as well.

Slope streaks also only appear on surfaces covered with a layer of fine dust, something that is obviously the case in the cool image to the right. There is so much dust on the surface here that bedrock only appears at the top of the ridge, peeking out in only a few places.

The location of this image, as shown in the overview map below, adds some additional details.

Overview map

Pavonis Mons is the central volcano of the three that sit between the giant canyon Valles Marineris to the east and Mars’ biggest volcano, Olympus Mons, to the west. The white rectangle marks the location of this photo, at the very base of Pavonis.

Thus, under the fine dust layers that allowed the formation of these slope streaks it is likely that all the rock is volcanic in nature, part of the vast lava flows that came down this volcano more than a billion years ago.

Why there is a ridge here is a little unclear. It appears that as the lava flowed downhill, it might have pushed debris in front of it, which piled up to form this higher ridge. (That is a pure uneducated guess, however.) Later, the dust piled up on the surface, allowing for slope streaks to appear periodically, likely instigated by a small rock fall at the top.

As for the streaks, the process that forms them remains unknown. Several theories have been proposed (dust flows, brine flows) but none really fits all the facts. They remain one of Mars’ many geological mysteries.

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 print edition can be purchased at Amazon. Or you can buy it directly from the author and get an autographed copy.

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

  • Lee Stevenson

    It seems to be “leaking” into a circular feature… That’s the only solution I can come up with.., another asteroid impact.,..

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