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Good morning, Rallypoint. Today's Astronomy Picture of the Day (APOD) is titled "A Hole in Mars." Captured in 2011 by the Mars Reconnaissance Orbiter (MRO), this image reveals a suspected opening to an underground cavern, partly illuminated on the image right. Analysis of this and follow-up images revealed the opening to be about 35 meters across, while the interior shadow angle indicates that the underlying cavern is roughly 20 meters deep. Could this be a view into a lava tube? On Earth, sometimes the tops of lava flows freeze on the surface even while the lava continues to move underground in a lava tube. If these tubes drain, then lava tube caves can be left behind. Sections of the roof may later collapse, creating roof openings, and these openings can be imaged from orbit. Is this a glimpse into the inner-plumbing of a Martian volcano?
APOD: 2020 March 1 - A Hole in Mars
Posted from apod.nasa.gov
NASA
Space
Science
Photography
Astronomy
Posted 5 y ago
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They probably should have edited that a bit- good Sunday mornign Maj William W. 'Bill' Price
LTC Stephen F. SP5 Mark Kuzinski COL Mikel J. Burroughs SMSgt Lawrence McCarter Maj William W. 'Bill' Price SPC Margaret HigginsMaj Bill Smith, Ph.D. SGT Steve McFarlandLTC (Join to see) PO3Craig Phillips Lt Col Charlie Brown SSG Michael Noll PO1 H Gene Lawrence TSgt Joe C. Lt Col John (Jack) Christensen Sgt (Join to see)SFC Joe S. Davis Jr., MSM, DSL SSG Donald H "Don" Bates Cpl (Join to see)PVT Mark Zehner
LTC Stephen F. SP5 Mark Kuzinski COL Mikel J. Burroughs SMSgt Lawrence McCarter Maj William W. 'Bill' Price SPC Margaret HigginsMaj Bill Smith, Ph.D. SGT Steve McFarlandLTC (Join to see) PO3Craig Phillips Lt Col Charlie Brown SSG Michael Noll PO1 H Gene Lawrence TSgt Joe C. Lt Col John (Jack) Christensen Sgt (Join to see)SFC Joe S. Davis Jr., MSM, DSL SSG Donald H "Don" Bates Cpl (Join to see)PVT Mark Zehner
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Maj William W. 'Bill' Price
Alan K. If it is a lava tube, it would dwarf those we know about here. Enhanced imagery shows the top of a debris pile 28 (~92 feet) meters down. The debris pile itself is estimated to be at least 62 meters (203 feet) tall. This tells us that the empty cavity was once 90 meters (295 feet) deep, prior to the collapse and infilling! Only a handful of caves on the Earth reach or exceed this size, and all those are from water-eroded limestone: not lava. It will be an interesting puzzle for someone to solve.
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