Difference between revisions of "March 11, 2010"
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=Peaks & Walls= | =Peaks & Walls= | ||
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<em>image by [mailto:slamm@blueyonder.co.uk Stefan Lammel]</em><br /> | <em>image by [mailto:slamm@blueyonder.co.uk Stefan Lammel]</em><br /> | ||
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| − | There are three central peaks in this snippet from a [http://www.pbase.com/slammel/image/122040536/original mosaic] from Stefan. The peak in Arzachel, the big crater in the middle, is more or less what we think lunar central peaks should look like, except for being off-center. The peak is a massive mountain, with straight-line wall segments that reach from its summit to the crater floor. It looks sort of rugged, like a mountain should. Contrast that with the odd, rounded central peak filling the floor of [ | + | There are three central peaks in this snippet from a [http://www.pbase.com/slammel/image/122040536/original mosaic] from Stefan. The peak in Arzachel, the big crater in the middle, is more or less what we think lunar central peaks should look like, except for being off-center. The peak is a massive mountain, with straight-line wall segments that reach from its summit to the crater floor. It looks sort of rugged, like a mountain should. Contrast that with the odd, rounded central peak filling the floor of [https://the-moon.us/wiki/Alpetragius Alpetragius] to the west. And with the somewhat similar rounded peak in [https://the-moon.us/wiki/file/detail/Rukl_55_satellites_NE.jpg Parrot C] to the east. Parrot C's peak is not as rounded as Alpet's - which Gerard Kuiper called an egg in a bird's nest - and doesn't fill the floor so completely. In fact, it is the walls of C and Alpet that look most alike. The erosional sequence of walls goes from a sharp rim crest scarp at Arzachel with somewhat rounded terraces, to Alpet where the scarp still exists but the inner wall has been completely erased/smoothed of any evidence to terraces. And C takes this one step further, with the smoothed walls extending al the way to the summit of the crater rim. Are these rounded peaks just the eroded version of a more typical mountainous peak? I don't think so. The Alpet peak is much wider in proportion to the crater floor than most peaks - Arzachel's peak could never be eroded enough to look like it. Perhaps the Alpet peak is the way most central peaks should look. A central peak forms by the rebound of ground zero. It always seemed strange that the rebound would be anything other than a broad upward swell - like the Alpet peak. Maybe we should be asking why most craters have small, non-rounded peaks?<br /> |
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<em>[mailto:tychocrater@yahoo.com Chuck Wood]</em><br /> | <em>[mailto:tychocrater@yahoo.com Chuck Wood]</em><br /> | ||
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<strong>Related Links</strong><br /> | <strong>Related Links</strong><br /> | ||
| − | Rükl plate [ | + | Rükl plate [https://the-moon.us/wiki/R%C3%BCkl_55 55]<br /> |
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| − | ---- | + | <p><b>Yesterday's LPOD:</b> [[March 10, 2010|Handheld Moon]] </p> |
| − | + | <p><b>Tomorrow's LPOD:</b> [[March 12, 2010|Wiggly Lines]] </p> | |
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Latest revision as of 18:51, 13 October 2018
Peaks & Walls
image by Stefan Lammel
There are three central peaks in this snippet from a mosaic from Stefan. The peak in Arzachel, the big crater in the middle, is more or less what we think lunar central peaks should look like, except for being off-center. The peak is a massive mountain, with straight-line wall segments that reach from its summit to the crater floor. It looks sort of rugged, like a mountain should. Contrast that with the odd, rounded central peak filling the floor of Alpetragius to the west. And with the somewhat similar rounded peak in Parrot C to the east. Parrot C's peak is not as rounded as Alpet's - which Gerard Kuiper called an egg in a bird's nest - and doesn't fill the floor so completely. In fact, it is the walls of C and Alpet that look most alike. The erosional sequence of walls goes from a sharp rim crest scarp at Arzachel with somewhat rounded terraces, to Alpet where the scarp still exists but the inner wall has been completely erased/smoothed of any evidence to terraces. And C takes this one step further, with the smoothed walls extending al the way to the summit of the crater rim. Are these rounded peaks just the eroded version of a more typical mountainous peak? I don't think so. The Alpet peak is much wider in proportion to the crater floor than most peaks - Arzachel's peak could never be eroded enough to look like it. Perhaps the Alpet peak is the way most central peaks should look. A central peak forms by the rebound of ground zero. It always seemed strange that the rebound would be anything other than a broad upward swell - like the Alpet peak. Maybe we should be asking why most craters have small, non-rounded peaks?
Chuck Wood
Technical Details
Aug 12, 2009. 10in f4.8 Newtonian, Infinity 2-1M, 5x Powermate, green filter, 150/3000, Avistack, Registax, PSE5, Focus Magic
Related Links
Rükl plate 55
Yesterday's LPOD: Handheld Moon
Tomorrow's LPOD: Wiggly Lines
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