[FPSPACE] Transient Lunar Phenomena: Regularity and Reality - 4 papers

[LARRY KLAES]

Transient Lunar Phenomena: Regularity and Reality

Authors: Arlin P.S. Crotts

(Submitted on 27 Jun 2007)

Abstract: Transient lunar phenomena (TLPs) have been reported for centuries, 
but their nature is largely unsettled. A review of TLP reports shows 
regularities in the observations; a key question is whether this structure 
is imposed by human observer effects, terrestrial atmospheric effects or 
processes tied to the lunar surface. I interrogate an extensive TLP catalog 
to determine if human factors determine the distribution of TLP reports. I 
divide the sample according to variables which should produce varying 
results if determining factors involve humans e.g., historical epoch or 
geographical location of the observer, not reflecting phenomena tied to the 
lunar surface. Regardless of how we split the ample, the results are 
similar: ~50% of the reports involve crater Aristarchus nd vicinity, ~16% 
from Plato, ~6% from other recent, major impacts, plus a few at Grimaldi. 
Mare Crisium produces a robust signal for three of five averages of up to 7% 
of the reports (however, Crisium is an extended feature). The consistency in 
TLP report counts for specific features indicates that >~80% of reports are 
consistent with being real (perhaps excepting Crisium). Some commonly 
reported sites disappear from the robust averages, including Alphonsus, Ross 
D and Gassendi. TLP reports supporting these sites originate almost entirely 
after year 1955, when TLPs became more popular targets of observation and 
many more (and inexperienced) observers searched for TLPs. In a companion 
paper, we compare the spatial distribution of robust TLP sites of transient 
outgassing (seen on Apollo and Lunar Prospector). To a high confidence 
against the random hypothesis, robust TLP sites and those of lunar 
outgassing correlate strongly, further arguing for the reality of TLPs. 
[Abstract abridged.]

Comments:  45 pages, 1 figure, submitted to ApJ. Other papers in series 
found at this http URL

Subjects:  Astrophysics (astro-ph)

Cite as:  arXiv:0706.3947v1 [astro-ph]

Submission history

From: Arlin Crotts [view email]

[v1] Wed, 27 Jun 2007 03:20:38 GMT (330kb)

http://arxiv.org/abs/0706.3947


Lunar Outgassing, Transient Phenomena and The Return to The Moon, I: 
Existing Data

Authors: Arlin P.S. Crotts

(Submitted on 27 Jun 2007)

Abstract: Herein the transient lunar phenomena (TLP) report database is 
subjected to a discriminating statistical filter robust against sites of 
spurious reports, and produces a restricted sample that may be largely 
reliable. This subset is highly correlated geographically with the catalog 
of outgassing events seen by the Apollo 15, 16 and Lunar Prospector 
alpha-particle spectrometers for episodic Rn-222 gas release. Both this 
robust TLP sample and even the larger, unfiltered sample are highly 
correlated with the boundary between mare and highlands, as are both deep 
and shallow moonquakes, as well as Po-210, a long-lived product of Rn-222 
decay and a further tracer of outgassing. This offers another significant 
correlation relating TLPs and outgassing, and may tie some of this activity 
to sagging mare basalt plains (perhaps mascons). Additionally, low-level but 
likely significant TLP activity is connected to recent, major impact craters 
(while moonquakes are not), which may indicate the effects of cracks caused 
by the impacts, or perhaps avalanches, allowing release of gas. The majority 
of TLP (and Rn-222) activity, however, is confined to one site that produced 
much of the basalt in the Procellarum Terrane, and it seems plausible that 
this TLP activity may be tied to residual outgassing from the formerly 
largest volcanic ffusion sites from the deep lunar interior. With the coming 
in the next few years of robotic spacecraft followed by human exploration, 
the study of TLPs and outgassing is both promising and imperiled. We will 
have an unprecedented pportunity to study lunar outgassing, but will also 
deal with a greater burden of anthropogenic lunar gas than ever produced. 
There is a pressing need to study lunar atmosphere and its sources while 
still pristine. [Abstract abridged.]

Comments:  35 pages, 3 figures, submitted to Icarus. Other papers in series 
found at this http URL

Subjects:  Astrophysics (astro-ph)

Cite as:  arXiv:0706.3949v1 [astro-ph]

Submission history

From: Arlin Crotts [view email]

[v1] Wed, 27 Jun 2007 03:34:43 GMT (572kb)

http://arxiv.org/abs/0706.3949


Lunar Outgassing, Transient Phenomena and The Return to The Moon, II: 
Predictions for Interactions between Outgassing and Regolith

Authors: Arlin P.S. Crotts, Cameron Hummels

(Submitted on 27 Jun 2007)

Abstract: We consider the implications from Paper I on how gas leaking 
through the lunar surface might interact with the regolith, and in what 
respects this might affect or cause the appearance of optical Transient 
Lunar Phenomena (TLPs). We consider briefly a range of phenomena, but 
concentrate at the extremes of high and low gas flow rate, which might 
represent the more likely behaviors. Extremely fast i.e., explosive, 
expulsion of gas from the surface is investigated by examining the minimal 
amount of gas needed to displace a plug of regolith above a site of gaseous 
overpressure at the regolith's base. The area and timescale of this 
disturbance, it is consistent with observed TLPs. Furthermore there are 
several ways in which such an explosion might be expected to change the 
lunar surface appearance in a way consistent with many TLPs, including 
production of obscuration, brightening and color changes. At the slow end of 
the volatile flow range, gas seeping from the interior is retained below the 
surface for extensive times due to the low diffusivity of regolith material. 
A special circumstance arises if the volatile flow contains water vapor, 
because water is uniquely capable of freezing as it passes from the base to 
the surface of the regolith. For a large TLP site, it is plausible to think 
of areas on the square-km scale accumulating significant bodies of water 
ice. Furthermore, as the system evolves over geological time, the ice 
accumulation zone will evolve downwards into the regolith. Since many 
reactions possible between the volatiles and regolith, depending on the 
additional gases besides water, can act to decrease diffusivity in the 
regolith, it is plausible that the volatiles produce a barrier between the 
seepage source and vacuum, forcing the ice zone to expand to larger areas.

Comments:  23 pages, 2 figures, submitted to ApJ. Other papers in series 
found at this http URL

Subjects:  Astrophysics (astro-ph)

Cite as:  arXiv:0706.3952v1 [astro-ph]

Submission history

From: Arlin Crotts [view email]

[v1] Wed, 27 Jun 2007 03:48:47 GMT (51kb)

http://arxiv.org/abs/0706.3952


Lunar Outgassing, Transient Phenomena and The Return to The Moon, III: 
Observational and Experimental Techniques

Authors: Arlin P.S. Crotts

(Submitted on 27 Jun 2007)

Abstract: In Papers II and III we show that Transient Lunar Phenomena (TLPs) 
are likely related to lunar outgassing, albeit in ways not fully understood. 
Here we propose a path forward, in which current and forthcoming 
technologies provide a more controlled, sensitive probe of lunar outgassing. 
Many of these techniques are being realized for the first time. Given the 
optical transient/outgassing connection, progress can be made by remote 
sensing, and we suggest programs of imaging, spectroscopy and combinations 
thereof. However, as found in Paper II, many aspects of lunar outgassing 
seem covert in nature. TLPs betray outgassing, but not all outgassing 
produces TLPs. Some outgassing may never appear at the surface, but remain 
trapped in the regolith. We also suggest more intrusive techniques, from 
radar mapping to in-situ probes. Understanding these volatiles seems 
promising in terms of a resource for humans on the Moon and beyond, and 
offers an interesting scientific goal in its own right. Hence this paper is 
a series of proposed techniques, some in practice, some which might be soon, 
and some requiring significant future investment, some of which may prove 
unwise pending results from predecessor investigations. These point towards 
enhancement of our knowledge of lunar outgassing, its relation to other 
lunar processes, and an increase in our understanding of how volatiles are 
involved in the evolution of the Moon. We emphasize certain ground-based 
observations in time for flights of SELENE, LRO and other robotic missions, 
and others before extensive human xploration. We discuss how study of the 
pristine lunar atmosphere pertains to understanding the role of 
anthropogenic volatiles, an important confusing signal

Comments:  33 pages, 4 figures, submitted to ApJ. Figures 5-6 and other 
papers in series found at this http URL

Subjects:  Astrophysics (astro-ph)

Cite as:  arXiv:0706.3954v1 [astro-ph]

Submission history

From: Arlin Crotts [view email]

[v1] Wed, 27 Jun 2007 04:20:31 GMT (814kb)

http://arxiv.org/abs/0706.3954