Difference between revisions of "June 21, 2012"

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=Hyping the Wrong Interpretation=
 
=Hyping the Wrong Interpretation=
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<em>topographic images credited to [http://www.nasa.gov/mission_pages/LRO/news/crater-ice.html" rel="nofollow NASA/Zuber, M.T. et al., Nature, 2012]</em><br />
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<em>topographic images credited to [http://www.nasa.gov/mission_pages/LRO/news/crater-ice.html NASA/Zuber, M.T. et al., Nature, 2012]</em><br />
 
<br />
 
<br />
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There is some water near the Moon's poles. LCROSS detected a [http://lpod.wikispaces.com/November+14%2C+2009 bucket full], and the Mini-RF radar <br />
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There is some water near the Moon's poles. LCROSS detected a [http://www2.lpod.org/wiki/November_14,_2009 bucket full], and the Mini-RF radar  
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of Chandrayaan-1 probably saw [http://lpod.wikispaces.com/March+2%2C+2010 more] than that. But there is no convincing evidence that the LRO <br />
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of Chandrayaan-1 probably saw [http://www2.lpod.org/wiki/March_2,_2010 more] than that. But there is no convincing evidence that the LRO  
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altimetry data (LOLA) discovered any at all, but that isn't the way the story is being told. In the <br />
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altimetry data (LOLA) discovered any at all, but that isn't the way the story is being told. In the  
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current issue of <em>[http://www.nature.com/nature/journal/v486/n7403/full/nature11216.html#/access" rel="nofollow Nature]</em>, Maria Zuber and colleagues report that the floor of Shackleton, a 21 km <br />
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current issue of <em>[http://www.nature.com/nature/journal/v486/n7403/full/nature11216.html#/access Nature]</em>, Maria Zuber and colleagues report that the floor of Shackleton, a 21 km  
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wide crater whose rim - one part - marks the South Pole, is brighter (at laser wavelengths) than other <br />
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wide crater whose rim - one part - marks the South Pole, is brighter (at laser wavelengths) than other  
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nearby crater floors. That could be due to it having about 22% water ice content. But the walls of <br />
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nearby crater floors. That could be due to it having about 22% water ice content. But the walls of  
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Shackleton are even brighter, including the parts occasionally illuminated by grazing sunlight. The <br />
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Shackleton are even brighter, including the parts occasionally illuminated by grazing sunlight. The  
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illuminated parts can not retain water ice so the Zuber team propose that it is bright, just as tens of <br />
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illuminated parts can not retain water ice so the Zuber team propose that it is bright, just as tens of  
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thousands of other crater walls are, because downslope movement constantly removes material dark-<br />
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thousands of other crater walls are, because downslope movement constantly removes material darkened by space weathering to expose fresh, unweathered soil. That is quite likely. Could there be two  
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ened by space weathering to expose fresh, unweathered soil. That is quite likely. Could there be two <br />
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explanations for brightness - the walls have an accepted, physically likely, if not certain, process at  
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explanations for brightness - the walls have an accepted, physically likely, if not certain, process at <br />
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work, and the floor brightness is due to a hoped for but mostly undocumented deposit of water ice?  
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work, and the floor brightness is due to a hoped for but mostly undocumented deposit of water ice? <br />
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It is possible, but I think unlikely. The <em>Nature</em> authors suggest that the most likely explanation is that  
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It is possible, but I think unlikely. The <em>Nature</em> authors suggest that the most likely explanation is that <br />
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the deep hole of a crater at a lunar pole protects the floor from space weathering, keeping it anomalously bright. Or deposition from comet impacts could create a micron thick water/ice layer. But the  
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the deep hole of a crater at a lunar pole protects the floor from space weathering, keeping it anomal-<br />
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downslope movement of wall debris must have coated the floor with more than a micron - the deepest  
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ously bright. Or deposition from comet impacts could create a micron thick water/ice layer. But the <br />
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that LOLA penetrates - of rock dust. Water ice at the top surface of any crater floor is very unlikely.  
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downslope movement of wall debris must have coated the floor with more than a micron - the deepest <br />
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But the NASA [http://www.nasa.gov/mission_pages/LRO/news/crater-ice.html press release] includes the word <em>ice</em> in its title and much of the story is about the  
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that LOLA penetrates - of rock dust. Water ice at the top surface of any crater floor is very unlikely. <br />
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interpretation that the authors dismiss. No wonder all the news stories are that this is a discovery of  
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But the NASA [http://www.nasa.gov/mission_pages/LRO/news/crater-ice.html" rel="nofollow press release] includes the word <em>ice</em> in its title and much of the story is about the <br />
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ice. With this much [http://en.wikipedia.org/wiki/Spin_(public_relations) spinning] of the evidence the hot air alone would melt any ice on the crater floor.
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interpretation that the authors dismiss. No wonder all the news stories are that this is a discovery of <br />
 
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ice. With this much [http://en.wikipedia.org/wiki/Spin_(public_relations)" rel="nofollow spinning] of the evidence the hot air alone would melt any ice on the crater floor.<br />
 
 
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<em>[mailto:tychocrater@yahoo.com" rel="nofollow Chuck Wood]</em><br />
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<br />
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<em>[mailto:tychocrater@yahoo.com Chuck Wood]</em><br />
 
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<strong>Technical Details</strong><br />
 
<strong>Technical Details</strong><br />
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<br />
 
<strong>Related Links</strong><br />
 
<strong>Related Links</strong><br />
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Rükl plate [http://the-moon.wikispaces.com/R%C3%BCkl+73 73]<br />
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Rükl plate [https://the-moon.us/wiki/R%C3%BCkl_73 73]<br />
 
<br />
 
<br />
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<p><b>Yesterday's LPOD:</b> [[June 20, 2012|A Little Volcanic Center]] </p>
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<p><b>Tomorrow's LPOD:</b> [[June 22, 2012|Hardly There]] </p>
 
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Latest revision as of 08:30, 28 October 2018

Hyping the Wrong Interpretation

LPOD-Jun21-12.jpg
topographic images credited to NASA/Zuber, M.T. et al., Nature, 2012

There is some water near the Moon's poles. LCROSS detected a bucket full, and the Mini-RF radar of Chandrayaan-1 probably saw more than that. But there is no convincing evidence that the LRO altimetry data (LOLA) discovered any at all, but that isn't the way the story is being told. In the current issue of Nature, Maria Zuber and colleagues report that the floor of Shackleton, a 21 km wide crater whose rim - one part - marks the South Pole, is brighter (at laser wavelengths) than other nearby crater floors. That could be due to it having about 22% water ice content. But the walls of Shackleton are even brighter, including the parts occasionally illuminated by grazing sunlight. The illuminated parts can not retain water ice so the Zuber team propose that it is bright, just as tens of thousands of other crater walls are, because downslope movement constantly removes material darkened by space weathering to expose fresh, unweathered soil. That is quite likely. Could there be two explanations for brightness - the walls have an accepted, physically likely, if not certain, process at work, and the floor brightness is due to a hoped for but mostly undocumented deposit of water ice? It is possible, but I think unlikely. The Nature authors suggest that the most likely explanation is that the deep hole of a crater at a lunar pole protects the floor from space weathering, keeping it anomalously bright. Or deposition from comet impacts could create a micron thick water/ice layer. But the downslope movement of wall debris must have coated the floor with more than a micron - the deepest that LOLA penetrates - of rock dust. Water ice at the top surface of any crater floor is very unlikely. But the NASA press release includes the word ice in its title and much of the story is about the interpretation that the authors dismiss. No wonder all the news stories are that this is a discovery of ice. With this much spinning of the evidence the hot air alone would melt any ice on the crater floor.

Chuck Wood

Technical Details
Colors show elevations - blue deep, orange and red high.

Related Links
Rükl plate 73

Yesterday's LPOD: A Little Volcanic Center

Tomorrow's LPOD: Hardly There

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