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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.

 

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Recent impact on Mars

Recent impact on Mars
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Cool image time! While finding recent impacts on Mars is not that unusual, the image to the right, found among the November image download from the high resolution camera on Mars Reconnaissance Orbiter (MRO), was dramatic enough that I decided that more people besides planetary scientists should see it. For scale the photograph is exactly 500 meters wide.

The photograph, taken September 26, 2019, also illustrates all the typical aspects of impact craters, and how they change the landscape.

This impact took place sometime between July 17, 2012 and January 4, 2018. We know this because it wasn’t there in a low-resolution image taken by the wide angle survey camera on MRO on the first date but was there when that same camera took another picture on the second date. Below is a side-by-side comparison of that July 17, 2012 image with the high resolution 2019 image above.

Before and after impact

The low resolution of the 2012 image makes it impossible to tell if the small craters in the high resolution 2019 image are new. Several look fresh, including the three inside the dark splotch. One or two beyond might have their own small dark aprons, suggesting they might be secondary impacts.

At the same time, this impact could have been caused by a relatively small bolide, which would then have been vaporized on impact and would have therefore left a very small crater. On that assumption, none of the craters here are new.

The asymmetric shape of the splotch itself suggests the three craters within it are new. To my eye it appears all three occurred at the same time, as the splotch seems extended sideways, as if it was made by three overlapping splotches centered on each crater.

To answer these questions, however, requires an understanding of impacts beyond my pay scale. It is possible that a researcher who studies these things would be able to estimate the bolide size from the size of the splotches, and thus determine whether or not the craters were produced by three simultaneous impacts from a object broken into three pieces.

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

  • Gary

    There are other curious features in the enlarged recent image such as the apparent dust devil track that makes a sharp right angle with one arm pointing right at the recent impact crater. Another is what appear to be parallel lines on the right side of the image running top to bottom. Some of the lines look like data drop-out, but others are surface features.

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