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On February 5, 2023 I will celebrate my 70th birthday. Yay! As I do every year during this birthday month, I run a campaign to raise money to support my work here at Behind The Black. I do not run ads. My only support comes from my readers, which leaves me utterly free to speak my mind openly about space, culture, and politics. Please consider supporting me in this work by giving either a one-time contribution or a regular subscription, in any one of the following ways:


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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Mapping the break-up and impact of one of the first asteroid’s tracked from space to the ground

Computer simulation of asteroid break-up
Click for full figure.

By analyzing 600 scattered pieces recovered from a 20-foot wide asteroid that broke-up and landed in the Sudan in 2008, scientists have discovered that some surface pieces were able to reach the ground unscathed because they were on the asteroid’s protected aft as it plowed through the atmosphere.

This asteroid was one of the first ever discovered shortly before impact and then tracked as it hit the atmosphere and broke up, the pieces falling as meteorites. The image to the right, figure 4 of the paper, shows the computer simulation of the asteroid’s break-up, based on the data obtained by mapping the location of its pieces on the ground. From the press release:

“Because of the high speed coming in, we found that the asteroid punched a near vacuum wake in the atmosphere,” says Robertson. “The first fragments came from the sides of the asteroid and tended to move into that wake, where they mixed and fell to the ground with low relative speeds.”

While falling to the ground, the smallest meteorites were soon stopped by friction with the atmosphere, falling close to the breakup point, while larger meteorites were harder to stop and fell further downrange. As a result, most recovered meteorites were found along a narrow 1-km wide strip in the asteroid’s path. “The asteroid melted more and more at the front until the surviving part at the back and bottom-back of the asteroid reached a point where it suddenly collapsed and broke into many pieces,” said Robertson. “The bottom-back surviving as long as it did was because of the shape of the asteroid.”

No longer trapped by the shock from the asteroid itself, the shocks from the individual pieces now repulsed them, sending these final fragments flying outwards with much higher relative speed. “The largest meteorites from 2008 TC3 were spread wider than the small ones, which means that they originated from this final collapse,” said Jenniskens. “Based on where they were found, we concluded that these pieces stayed relatively large all the way to the ground.”

The location of the large meteorites on the ground still reflects their location in the back and bottom-back part of the original asteroid.

While there is a certain randomness in how any asteroid breaks up, this data will help scientists better understand the make-up of future meteorites they find. The bigger more widely scattered pieces likely came from the asteroid’s rear surface.

Conscious Choice cover

Now available in hardback and paperback as well as ebook!


From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.

Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.  
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.


“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.


All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.


Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.

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