Comparative analyses of observations of lunar transient phenomena

Abstract

From the author's collection of more than 900 reports of Lunar Transient Phenomena (LTP) covering the period 1540–1970, 771 positive plus 112 negative observations (several times more than any previously published analyses) with sufficient ancillary data were analyzed for five hypotheses of causes. Approximately one third were of Aristarchus, divided almost equally between one observer, Bartlett, and all others. Treated as two groups they were divided into four categories: (1) gaseous, (2) reddish, (3) bluish, and (4) brightenings, and analyzed separately and combined with respect to the hypotheses. Six other individual LTP sites also were analyzed. The five hypotheses involved effects of tides, sunrise, low-angle illumination, Earth's magnetic tail, and solar particles. Novel analyses were made by [1] histograms with respect to (a) phase (φ) of anomalistic period, (b) Moon's age; [2] plot on a representative cycle of anomalistic orbits; [3] ratios of observed to expected percentages ( O E ); [4] plot of distributions of (a) LTP sites (<100), (b) dark, flat-floored craters, and (c) the author's (1967) ringdike candidates. The histograms show: [1] caprice in analytical behavior between (a) the sites individually, even between near neighbors, and collectively, (b) the different categories, and (c) Bartlett and All Others, especially in φ: [2] any tidal correlations found were almost exclusively with perigee; [3] in lunar age, rather persistent correlations were found with feature sunrise and with the magnetic tail; [4] differences between Bartlett and All Others for the reddish phenomena, and similarities between the Bartlett bluish and All Others' brightenings suggest variant optical physiological responses, indicating higher blue-sensitivity and and lower(?) red-sensitivity for Bartlett; [5] inverse relationships between Bartlett's gaseous and reddish phenomena in both tidal and age diagrams, and the same inverse relation between his reddish and All Others' suggest that Bartlett glimpsed true ground color in the absence of obscuring matter; [6] the sharp perigee and apogee correlations found by Burley and Middlehurst (1966) smeared out or disappeared in the much larger number of observations of all sites analyzed here. Most perigee or apogee correlations clustered more at times of greater orbital eccentricity than at lesser eccentricity, as shown by the orbital plot; [7] absent and present (especially the onset) phenomena correlated similarly, instead of oppositely as expected, and both were found to advance around the orbits on the orbital plot, which weakens any positive correlations found; [8] phenomena have been reported for all ages, from O d to 28 d with >50% within ±4 d of full Moon ( < 1 4 near perigee). The ratios ( O E ) revealed: [1] universely high correlations with sunrise, not all accountable by observational selection; [2] rather high correlation with Earth's magnetopause, but not the bow-shock front turbulence; [3] decline of perigee correlation with increasing number of observations, from ( O E ) = 1.9 to 1.1 ; [4] little correlation with direct bombardment of solar flare particles but apparent enhancement by the magnetic tail when the Moon was within it at time of arrival of the particles in the Earth-Moon system. Some facts indicate that some of the brightenings result from unknown atmospheric, instrumental, and geometric effects, but many puzzling aspects still remain. Comparison of the distributions (nonrandom) of the LTP sites, dark craters, and the author's proposed ringdikes shows strong affinities for the mare edges for each, implying internal activity (probably degassing) as the source of most LTP. Considering everything the data show, the author is skeptical that there are any decisive external (even tidal) influences on this internal activity released at LTP sites.