Moon’s south pole permanently shadowed regions are younger than expected
Click for original image.
A new long range model of the Moon’s orbit and rotational tilt now suggests that the permanently shadowed regions (PSRs) in its south polar regions are much younger than previous predicted, which reduces the likely amount of ice that has been preserved there.
The map of the south pole region to the right, reduced, sharpened, and annotated to post here, shows the locations of those shadowed regions, with their predicted ages indicated by the colors (Gyr = billion years). Note that the Nova-C lander, planned for launch in mid-November, will land somewhat near some relatively young PSRs, as indicated by the red cross. From the press release:
“We calculated the lunar spin axis orientation and the extent of PSRs based on recent advances for the time evolution of the Earth-Moon distance,” he said. Early in its history, the Moon (which is 4.5 billion years old) was bombarded by comets and volcanism released water vapor from its interior, but continuously shadowed areas started to appear only 3.4 billion years ago. By that time these processes had started to die down, so most of the water that was delivered to the Moon or outgassed from its interior could not have been trapped in the polar regions. Any ice in the polar regions today must have a more recent origin.
“We have been able to quantify how young the lunar PSRs really are,” Schorghofer said. “The average age of PSRs is 1.8 billion years, at most. There are no ancient reservoirs of water ice on the Moon.”
Since other data suggests the presence of ice, it is possible that these reserves are regularly renewed by the arrival of impacts. It also suggests however that there might be less ice available than hoped. Above all, the red colored regions appear to be the most valuable real estate to explore first.
Note: The landing sites for both India’s Vikram lander and Russia’s Luna-25 lander were well beyond the map’s upper right edge, far outside the region where any permanently shadowed craters are located. The news outlets that talked about finding water or ice on either mission were simply illustrating their ignorance and sloppy reporting.
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
Click for original image.
A new long range model of the Moon’s orbit and rotational tilt now suggests that the permanently shadowed regions (PSRs) in its south polar regions are much younger than previous predicted, which reduces the likely amount of ice that has been preserved there.
The map of the south pole region to the right, reduced, sharpened, and annotated to post here, shows the locations of those shadowed regions, with their predicted ages indicated by the colors (Gyr = billion years). Note that the Nova-C lander, planned for launch in mid-November, will land somewhat near some relatively young PSRs, as indicated by the red cross. From the press release:
“We calculated the lunar spin axis orientation and the extent of PSRs based on recent advances for the time evolution of the Earth-Moon distance,” he said. Early in its history, the Moon (which is 4.5 billion years old) was bombarded by comets and volcanism released water vapor from its interior, but continuously shadowed areas started to appear only 3.4 billion years ago. By that time these processes had started to die down, so most of the water that was delivered to the Moon or outgassed from its interior could not have been trapped in the polar regions. Any ice in the polar regions today must have a more recent origin.
“We have been able to quantify how young the lunar PSRs really are,” Schorghofer said. “The average age of PSRs is 1.8 billion years, at most. There are no ancient reservoirs of water ice on the Moon.”
Since other data suggests the presence of ice, it is possible that these reserves are regularly renewed by the arrival of impacts. It also suggests however that there might be less ice available than hoped. Above all, the red colored regions appear to be the most valuable real estate to explore first.
Note: The landing sites for both India’s Vikram lander and Russia’s Luna-25 lander were well beyond the map’s upper right edge, far outside the region where any permanently shadowed craters are located. The news outlets that talked about finding water or ice on either mission were simply illustrating their ignorance and sloppy reporting.
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
Would somebody please land in one of these craters and figure out if there’s ice there? I want my $8700 3.3 billion year vintage lunar water ice aphrodisiac already.
How do we know the interior of the Moon has water? Is there some type of seismographic test that was completed? I wonder, was that completed 3 billion years ago?
I suspect that there have been some very clever seismographic testing (by Apollo equipment?) or Earth to Moon laser ranging to retro reflectors left by Apollo that may have indicated, in some way, there is water in the Moon’s interior – but I am unaware of this.
How do we know that the permanently shadowed regions (PSR) started to appear 3.4 billion years ago. Do we have that great a record or model of the Moon’s orbit, precession and nutation across 3 or more billion years to know they only would have started to appear then?
There may be excellent data here, and I will concede to that DATA. However, given the unknowns of even three-body gravitational systems, I wonder how we can make such claims on such billion-year-old systems.
I looked for a “we think” but didn’t see one. They do speak of theory on the Earth-Moon distance and the change due to a “deep past” “change”; but the then attributing of taking “their result” (French group) into a projection/belief took me as a bit too far.
Perhaps this is the way of this part of forensic orbital mechanics (my made-up term), but it seems a bit out on a limb.
First time I’ve seen the term “gigayears”
Andi: Scientists have been using this term for years, for reasons that baffle me. It appears mostly to create obscure jargon that makes their work seem more intelligent. Instead, it continues to give me a livelihood, translating their work into plain English. :)
So, Myr works for million and mega.
Seems like Shackleton is the prime real estate.
Back in the day at school, when we all had to carry the “Engineer’s bible” (aka CRC Handbook), we used to waste our time looking up the most obscure units we could find.
Although some could actually be useful in daily life (mFn – millifortnight – about 20 min) (uFn – microfortnight – 1.2 sec)