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Фотометрический анализ вулканических влияний на проницаемость атмосферы. Исследование конкретных случаев т. н. невидимых затмений и вулканической активности. Доказательство наличия связи в некоторых случаях.

Юнте определил распреселение азрозолей в атмосфере до высоты 30 км, а также их распределение по радиусам. Зтих данных достаточно для получения полуколичественного предсатвления о влиянии азрозолей на яркость лунных затмений. Расчеты покзали, что зтим влиянием можно пренебречв и что различия между наблюденной и рассчитанной тенью возникают в слоях выше 30 км.

International audience; The Chang'E-5 mission is the third phase of the Chinese Lunar Exploration Program and will collect and return lunar samples. After sampling, the Orbiter and the ascent vehicle will rendezvous and dock, and both spacecraft will require high precision orbit navigation. In this paper, we present a novel tracking mode-Four-way lunar Lander-Orbiter tracking that possibly can be employed during the Chang'E-5 mission. The mathematical formulas for the Four-way lunar Lander Orbiter tracking mode are given and implemented in our newly-designed lunar spacecraft orbit determination and gravity field recovery software, the LUnar Gravity REcovery and Analysis Software/System (LUGREAS). The simulated observables permit analysis of the potential contribution Four-way lunar Lander Orbiter tracking could make to precision orbit determination for the Orbiter. Our results show that the Four-way lunar Lander Orbiter Range Rate has better geometric constraint on the orbit, and is more sensitive than the traditional two-way range rate that only tracks data between the Earth station and lunar Orbiter. After combining the Four-way lunar Lander Orbiter Range Rate data with the traditional two-way range rate data and considering the Lander position error and lunar gravity field error, the accuracy of precision orbit determination for the Orbiter in the simulation was improved significantly, with the biggest improvement being one order of magnitude, and the Lander position could be constrained to sub-meter level. This new tracking mode could provide a reference for the Chang'E-5 mission and have enormous potential for the positioning of future lunar farside Lander due to its relay characteristic. (C) 2016 COSPAR. Published by Elsevier Ltd. All rights reserved.

The correlation between the b-values of acoustic emissions (AEs) and the phase of the moon was investigated at the Underground Research Laboratory (URL) in Canada. The same data as those used in Iwata (2002) were examined, which showed that the occurrence of AEs is correlated with the phase of the moon. It was expected, therefore, that the b-value of the AEs would also be sensitive to tidal stress/strain fluctuations. We investigated the variation of the b-values as a function of the phase of the moon. Results show that b-values immediately following the times of full/new moon are higher than those at other times. Using AIC (Akaike Information Criterion) and random (Monte Carlo) simulations, it was confirmed that this feature is statistically significant. We also investigated whether or not there was a change in the b-values immediately before the times of full/new moon, but no statistically significant change was observed. The results suggest that the effect of stress/strain fluctuations on AE occurrences at the URL is asymmetric to the times of full/new moon.

The impact of the Lunar Prospector spacecraft in a lunar polar crater was used in an (unsuccessful) attempt to detect the release of vapor from volatilized water ice. The short-time evolution of such an impulsively produced atmosphere is discussed. The effects of the initial vapor temperature (and thus its initial molecular thermal velocity) and the nature of the gas-surface interaction are examined parametrically. It is shown that the exosphere quickly diffuses to the nightside of the Moon. The results have implications for observations of impulsive gas releases on airless bodies in general.

Lunar Prospector gamma-ray spectrometer data for surface thorium indicate that craters greater than about 60 km in diameter tend to excavate into materials less Th-rich than the surface regolith. For the largest 12 craters and basins amenable to this type of analysis (diameters between 90 and 930 km), the ratio of crater (or basin) Th concentration to regional background Th averages 0.76±0.13. This trend implies a pronounced diminution in average Th concentration with increasing depth (down to roughly 30 km deep) in the lunar crust. Assuming deep-origin Orientale ejecta was strongly diluted by turbulent basin-modification mixing, an even more pronounced depth-Th anticorrelation would be indicated by extrapolation of the trend of the 30–300 km craters to higher diameters, i.e., deeper excavations. In any case, the overall lunar crust, and by extension the bulk Moon, is probably far less Th-rich than a simple averaging of surface compositions would suggest.

The present rate of tidal dissipation in the Earth-Moon system is known to be anomalously high, in the sense that the implied age of the lunar orbit is only 1.5×109 years, though other evidence suggests an age closer to 4×109 years. To assess how long the anomalous dissipation has persisted, we use published estimates of lunar orbital configurations derived from (a) fine grained sediments containing tidal laminations and (b) numerical ocean models averaged over varying ocean geometries. The implied histories of the lunar semimajor axis are surprisingly consistent over the past 109 years. The ocean models imply, on average, reduced dissipation in the past because of a spatial mismatch between tidal forcing and oceanic normal modes of higher frequencies. Webb's ocean model suggests that the “anomalous” oceanic dissipation began about 109 years ago and has been increasing since then.

Lunar Prospector data support the contention that water ice reservoirs exist in the permanently shaded craters near the lunar poles. Yet the question remains whether the detected hydrogen abundance is actually water ice or is hydrogen in some other form. Present plans call for a controlled impact of Lunar Prospector into a polar crater at the end of July, 1999, in an attempt to liberate a small amount of water vapor that may be detected by ground- and space-based observatories. A positive spectral detection of water vapor or its photo-dissociated byproduct, OH, would be definite proof of the presence of water ice in the regolith. The following represents both an analysis of this method of searching for water ice as well as an announcement to the observing community of the event.

Night-time measurements using a bare CCD all-sky imaging system have detected the presence of an extensive region of neutral sodium emission (589.1 nm) in the direction of the anti-solar/lunar points. The emission was observed to occur during the nights of 21–22 August and 18–20 November, 1998 UT, centered on the new Moon period. The Moon is the most likely source of the neutral sodium, making this the first detection of the lunar sodium tail out to a distance of hundreds of lunar radii. The greater brightness of the emission feature on 19 November is attributed to the Leonid meteor shower which peaked on 17 November, 1998, less than two days before new Moon.

Recent remote sensing data strongly suggest that deposits of ice occur in permanently shadowed regions at the lunar poles. Clementine, by providing the first contiguous coverage of the Moon, has enabled the production of an illumination map of the south pole. This map shows the extent of the areas of permanent darkness during winter in this region as well as identifying places on the lunar surface that receive illumination for more than 50% of the lunar day. The permanently dark areas are prime candidates for locations of ice deposits while regions that are illuminated for anomalous periods are possible sites for lunar bases. In this paper we study in detail the illumination history during a lunar day of some of these sites. While we find no area that receives permanent illumination, we do find two areas, only 10 km apart, which collectively receive sunlight for over 98% of the time.

The equipotential surface hypothesis suggests that lunar maria floors lie on a surface parallel to the selenoid. This is examined using the spherical harmonic representations of the Clementine topography and Lunar Prospector gravity data. It is demonstrated that the floors of both circular and noncircular maria significantly deviate from an equipotential surface. Deeper circular maria and the deeper part of the noncircular Maxe Tranquillitatis have been subsided under larger mass loads in the crust. We calculate the mass beneath the maria to be in excess to the mass required for isostatic compensation of the topography at 60 km depth. A global map of this excess mass shows that the noncircular maria are isostatically compensated, unlike the circular maria. The map also reveals seven new sizable mascons: the three largest are associated with Mendel-Rydberg, Mare Humboldtianum, and Mare Moscoviense.

We use newly developed spectroscopic methods for determining FeO and TiO2 abundances to study the huge (2500 km diameter) South Pole-Aitken basin. The floor of this basin shows iron and titanium values which are weakly correlated and largely range from 7 to 14 wt % FeO and from 0.5 to 1.5 wt % TiO2. This composition is consistent with an approximate 1:1 mixture of lower crustal material like that found elsewhere on the Moon and mantle rock containing 10–16 wt % FeO and

A short general explanation of tidal forces and tidal effects is given. The influences of Earth tides and ocean tides on the Earth's rotation vector are presented. Today, the theoretical models for periodic variations in the Earth's rotation and in polar motion can be compared with precise measurements done by modern space techniques. Secular changes of the Earth's rotation due to interactions within the Earth-Moon-system are also discussed.

During the ATLAS-3 mission on the Space Shuttle Atlantis (STS-66) in November of 1994, a unique opportunity arose that enabled the solar-viewing instruments to observe ultraviolet radiation from the Moon. During these observations the Moon was at a phase angle of 51.8°. Measurements by the Shuttle Solar Backscatter Ultraviolet (SSBUV) instrument indicate lunar geometric albedo values, after correction to full moon, of 4.4%–8.3% in the wavelength range from 250 nm to 400 nm. These results are in good agreement with past measurements.

We present observations of precursor ULF wave activity and energetic electron flows detected by the WIND spacecraft just prior to entry of the lunar wake on 27 December 1994. This activity occurs upstream of the wake on field lines directly connected to the wake penumbra region. The activity ceases near the penumbra entrance. The observations of upstream ULF wave activity and solar wind counterstreaming electron flows is similar to observations made upstream of collisionless bow shocks. Analogously, the wake precursor region is characterized by thermalization and information propagation ahead of the wake structure.

The Crisium basin region harbors a number of interesting features, including geochemical and radar anomalies, light plains units and possible hidden mare deposits (cryptomaria). This report presents preliminary results of a telescopic near-infrared spectral study concerning a variety of surface units in the Crisium region. Observations were made of Mare Crisium, light plains deposits north of Taruntius crater, and the terra associated with the Crisium basin.

The objective of the unified lunar control network is to combine a series of control networks into one compatible network with its origin at the center of mass of the Moon and its coordinates referred to the mean Earth/polar axis system. The initial unified system contained 130 nearside points from Apollo data and 1026 from telescopic data. It also contained ten Mariner 10 points. The total number of points was 1166. The current network includes modifications to the past network and extends the coverage. Coordinates of points north of the Apollo region have been recomputed based on Galileo images from the second Earth-Moon flyby. Coordinates of points in the Apollo region were held fixed; however, coordinates of points north of the Apollo region in the telescopic region and many Mariner 10 points were recomputed. All of the Mariner 10 points were remeasured and integrated into the network. Additional points in the Apollo region including the farside have been added. The unified network now contains 1478 points. Apollo, Mariner 10, and Galileo pictures all contained some farside points. The coordinates of the 1478 points are available only in the microfiche supplement to this paper.

One of the most important inferences of the Lunar Prospector mission data was the existence of subsurface water ice in the permanently shadowed craters near both lunar poles [Feldman et al., 1998]. We propose and substantiate an alternative explanation that hydrogen can exist in the shallow lunar subsurface in the form of clathrate hydrates: CH4 . 6H(2)o and/or CO2 . 6H(2)o.

It is pointed out that the implication of the popular giant impact model of lunar origin (e.g., Hartmann and Davis, 1975; Cameron and Ward, 1976; Stevenson, 1987) is that any depth-related silicate differentiation within the impactor (and/or the earth) at the time of the impact must be partly inherited by the preferentially peripheral matter that forms the moon. This paper presents calculations of the magnitude of the net differentiation of the protolunar matter for a variety of elements and scenarios, with different assumptions regarding the geometries of the 'sampled' peripheral zones, the relative proportions of the earth-derived to impactor-derived matter in the final moon, and the degree to which the impactor mantle had crystallized prior to the giant impact. It is shown that these differention effects constrain the overall plausibility of the giant impact hypothesis.

To understand the possible large scale influence of Titan on its plasma environment, we study the magnetic fields and plasma measurements, both when Cassini flies close to Titan and when Cassini crosses the moon's orbit far from it. Using 98 Cassini passes from 06/2004 to 12/2008, we examine the plasma environments at the orbit of Titan with the moon present and absent. In particular, the presence of Titan appears to affect the magnetopause location. Near noon, the Saturn magnetopause is more frequently inside of Titan's orbit with the moon absent than with it present. Titan's presence near noon appears to locally enhance the total pressure and reduce the magnetosphere compressibility, possibly by mass-loading. Near local midnight, the stretching and sweepback angles for cases with Titan present and absent suggest that the moon enhances the tail reconnection rate, in agreement with previous studies of the moon's influence on the Saturnian magnetosphere.

Accepted: 2009-09-02, 資料番号: SA1000796000

[1] We have calculated evaporation rates for a range of organic compounds that may be cold-trapped at the poles of the Moon and Mercury. Organics vary widely in their volatilities and thus can be stable to evaporation at higher and lower temperatures than water. The detection of cold-trapped organics would point to volatile delivery by impacts, as comets and asteroids are the only plausible sources for organic molecules. The characterization of cold-trapped organics on both bodies may provide constraints on the thermal evolution of cold traps over time and the history of volatiles in the inner solar system.

[1] Dust is the Number 1 environmental hazard on the Moon, yet its movements and adhesive properties are little understood. Matchbox-sized, 270-gram Dust Detector Experiments (DDEs) measured contrasting effects triggered by rocket exhausts of Lunar Modules (LM) after deployment 17 m and 130 m from Apollo 11 and 12 LMs. Apollo 11 Lunar Seismometer was contaminated, overheated and terminated after 21 days operation. Apollo 12 hardware was splashed with collateral lunar dust during deployment. DDE horizontal solar cell was cleansed of nominally 0.3 mg cm−2 dust by 80% promptly at LM ascent and totally within 7 minutes. A vertical cell facing East was half-cleaned promptly then totally over hundreds of hours. Each cell cooled slightly. For the first time lunar electrostatic adhesive forces on smooth silicon were directly measured by comparison with lunar gravity. Analyses imply this adhesive force weakens as solar angle of incidence decreases. If valid, future lunar astronauts may have greater problems with dust adhesion in the middle half of the day than faced by Apollo missions in early morning. A sunproof shed may provide dust-free working environments on the Moon. Low-cost laboratory tests with DDEs and simulated lunar dust can use DDE benchmark lunar data quickly, optimising theoretical modelling and planning of future lunar expeditions, human and robotic.

[1] Using new SMART-1 AMIE images and Arecibo and Goldstone high resolution radar images of the Moon, we investigate the geological relations of the south pole, including the 20 km-diameter crater Shackleton. The south pole is located inside the topographic rim of the South Pole-Aitken (SPA) basin, the largest and oldest impact crater on the Moon and Shackleton is located on the edge of an interior basin massif. The crater Shackleton is found to be older than the mare surface of the Apollo 15 landing site (3.3 Ga), but younger than the Apollo 14 landing site (3.85 Ga). These results suggest that Shackleton may have collected extra-lunar volatile elements for at least the last 2 billion years and is an attractive site for permanent human presence on the Moon.

[1] Substorms play an important role in the energization and transport of plasmas in planetary magnetospheres, including the shedding of the mass added by moons in the case of Jupiter and Saturn. Mass shedding occurs through rapid reconnection in the near tail resulting in dipolarization on the magnetospheric side of the reconnection point and plasmoid formation down tail. Observations of these sudden reconnection events in Saturn’s near-tail region provide additional insight into this process. Saturnian substorms, at least on occasion, have a plasmoid formation phase leading to a traveling compression region. Changes in the field strength across reconnection events suggest that open flux has been removed from the tail. The timing of tail reconnection events appears to be controlled by both the orbital phase of Titan, and the variable stretching of the near-tail field as Saturn rotates.

The frequency of earthquake incidence along the Andaman/Sunda/Java Trench plate-boundary region has been investigated for the ten-lunar-month period 28 October 2004–19 August 2005, encompassing the 26 December 2004 earthquake. During this period variations in earthquake activity correlate with the tidal-force cycles: maxima in earthquake activity occur around the times of new and full moons, typically lagging by 0–3 days. This relationship is consistent with earthquake inducement via ocean tidal loading. Also, during this period the earthquake incidence associated with new and full moons at the western end of the region was (a) 38% and (b) 86% higher than the period averages for the full and declustered major-earthquake catalogs respectively.

[1] Scientists for different regions of the world have indicated the impact of lunar cycle on different climatic parameters including precipitation. In the present study the impact of the lunar cycle on the precipitation in India has been analyzed. Daily precipitation records were assembled for 129 stations spread across the subcontinent for the time period 1910 to 2000. The results of the study indicate a general tendency towards the increased occurrences of precipitation a few days after the full moon in the interiors. The west coast of India showed tendency towards higher precipitation amounts in the ascending phase of the lunar cycle.

[1] The MCNPX radiation transport code is used to simulate cosmic ray interactions within the Moon. Accurate source, geometric, and physics models are developed to successfully benchmark neutron density results with Apollo 17 measurements. The peak of the MCNPX lunar neutron density profile is shown to be within a few percent of the measured value, using a galactic cosmic rays modulation parameter that is consistent with the timeframe of the Apollo 17 mission. Sensitivity of the density profile to various input parameters and physics options is considered. Details of the simulation input are provided, along with neutron production and flux results, to facilitate additional benchmark efforts in the future.

In our recent work on radon in UK homes the authors have observed tidal-periodic variations in built-environment radon levels and here report results from our ongoing investigations. These tidal variations have been quantified using a variety of analytical techniques, including a novel correlation technique developed as part of this investigation. The observed variations are cyclic at the 14-15 day tidal period and lag new/full moons by varying periods of days, the magnitude of the variation and lag being dependent on factors such as location, underlying geology and rock/soil hydration. As well as quantification and discussion of tidal effects on radon levels, the potential effects of such phenomena on the reliability of short-term radon measurements are discussed.

[1] We study the correlation between the phase of the moon and the occurrence of microearthquakes in the Tamba region, close to the fault of the 1995 Kobe earthquake. The existence of the correlation during the two-year period following the Kobe earthquake was suggested in a previous study. First, in this study, we investigate the statistical significance of such correlation. Using point-process modeling and AIC (Akaike Information Criterion), we confirm that the existence of the correlation is statistically significant. Second, we investigate the temporal variation of the correlation during the four-year period following the Kobe earthquake. The result of the second analysis indicates that the correlation is strongest just after the Kobe earthquake and that it then becomes weaker year by year.

[1] The northwest portion of the Moon's South Pole-Aitken basin contains an anomalously high abundance of thorium as determined by Apollo and Lunar Prospector gamma-ray spectroscopy. The anomaly's proximity to the antipode of the Imbrium basin has led several investigators to suggest that the anomaly is the result of convergence of thorium-enriched ejecta from the Imbrium impact. Examination of this complex region with new higher-resolution thorium data and several other datasets reveals that a convergence of ejecta cannot explain the anomaly. Alternatively, we propose an indigenous and likely ancient source.

[1] An effort to find farside deep moonquakes among the recently discovered nests of deep moonquakes has identified about 30 nests that are likely to be on the farside. Although only a few of them are locatable with currently available data and those few provide little new information about the deep interior of the Moon, the inferred distribution of the rest of these nests indicates that either the region of the Moon's deep interior within about 40 degrees from the antipode of the Moon is nearly aseismic or, alternatively, the very deep interior of the Moon severely attenuates or deflects seismic waves. Since this has important bearing on the origin and evolution of the Moon, future missions to the Moon need to be oriented toward resolving this uncertainty. Some limited data favor the attenuation/deflection hypotheses.

Two types of meteoritic events are associated with the calendric period June 13–30. One is an excess of falls of certain basaltic meteorites. These comprise a new subgrouping of achondrites (designated “NUJ”) whose lithologies suggest possibly similar preterrestrial histories. Historical high-energy impact-like events on the Earth and Moon have also occurred in late June. In addition to much studied events in 1178, 1908 (Tunguska), and 1975, these include an impact-like lunar event known to Islamic scholars whose occurrence in 617 A.D. may have been June 26–27.

[1] By following the trajectories of a large number of particles we capture the seasonal variations of the density and spatial distributions of dust in Saturn's E-ring. We have used an optimized set of parameters from our earlier azimuthally symmetric ring model [Juhasz and Horanyi, 2002] to match remote sensing, and in situ observations as well. The model will be tested by the upcoming Cosmic Dust Analyzer (CDA) measurements onboard Cassini. It will be useful to find regions in the E-ring where the source moon of the detected dust grains can be identified. In these regions CDA measurements of the chemical composition of the dust particles will enable us to learn about the surface properties of their moon of origin.

[1] An analysis of simple craters in the lunar polar regions has produced new values for the minimum amount of permanent shadow in these areas, 7500 km2 and 6500 km2, for the north and south pole respectively. These values were obtained by conducting illumination simulations of realistically shaped simple craters

[1] Investigating mare basalt compositions, at both the sample and remote-sensing level for the Apollo and Luna mare sites, reveals the need for a more complex regression procedure than previously proposed in order to extract accurate TiO2 concentrations from Clementine spectral reflectance (CSR) data. The TiO2 algorithm of Lucey and coworkers is modified by using two different sets of regression parameters to relate measured regolith compositions from sampling locations to the CSR properties of these sites. One regression trend fits the majority of Apollo data, and the second regression is a fit to the Apollo 11, Luna 16, and Luna 24 data, which were considered to be anomalous in previous TiO2 calibrations. These three sites have unusually low albedo compared to other mare landing sites, and some 32% of nearside mare regions appear to share this characteristic. Possible reasons for these differences related to proximity of the other sites to mare-highland boundaries are discussed. Using the dual-regression method, we find (1) that TiO2 concentrations calculated for the basaltic landing sites faithfully reproduce a bimodal distribution as seen in the sample data, (2) that when coupled with the effects of other thermal neutron absorbers, Ti concentrations are more consistent with observed epithermal-to-thermal neutron-flux ratios than are previous Clementine-based derivations of TiO2 for basaltic regions, and (3) that basalts of intermediate-TiO2 concentrations occur most frequently in the Oceanus Procellarum region and that these intermediate concentrations appear to be inherent to the flows underlying the regolith and presumably to the basalt source regions.

Research at the University of California, Berkeley, was supported by NASA through subcontract LRI-99-101 from the Lunar Research Institute.

The inside of Shackleton Crater at the lunar south pole is permanently shadowed; it has been inferred to hold water-ice deposits. The Terrain Camera (TC), a 10-meter-resolution stereo camera onboard the Selenological and Engineering Explorer (SELENE) spacecraft, succeeded in imaging the inside of the crater, which was faintly lit by sunlight scattered from the upper inner wall near the rim. The estimated temperature of the crater floor, based on the crater shape model derived from the TC data, is less than ∼90 kelvin, cold enough to hold water-ice. However, at the TC's spatial resolution, the derived albedo indicates that exposed relatively pure water-ice deposits are not on the crater floor. Water-ice may be disseminated and mixed with soil over a small percentage of the area or may not exist at all.

The altitudes of the Sun and Moon have been calculated for the 541 great earthquakes (those with magnitude ⩾ 7.5) that occurred between 1897 and 1985. There is a tendency for more earthquakes to occur when the Sun or Moon is at an altitude of 30–50° above the horizon than would be expected by chance. Though neither the lunar nor the solar result is of high significance in itself, the experiments are independent so they may be combined, when they yield a significant result.

The largest members in longitude and latitude of the theoretical movement of the earth's moon, developped byHill 1891 fromDelaunays theory of the moon, have been here calculated with new, now better known numerical values. Effectively a highly better accordance of the observed values with the theoretical ones has been obtained. This method will be able to give an important contribution to the determination of the figure of the earth with regard to the geometrical and the static flattening, specially by moons observation material of 1850–1950. Les membres les plus grands en longitude et latitude du mouvement theorique de la lune developpes parHill 1891, fondes sur la theorie deDelaunay, sont ici calcules avec de nouvelles valeurs numeriques de meilleure connaissance. C'est pourquoi une bonne accordance est obtenue des valeurs observees avec les valeurs theoriques. La methode donne une contribution importante a la determination de la figure de la terre par rapport a l'aplatissement geometrique et l'aplatissement statique, principalement par egard aux observations de la lune 1850–1950.

The artificial moon, projected from serious scientists, presents, whenever previously without reality, a field of interesting theoretical problems. At first the figure of movement of the body itself within the varying gravity field, further more its observation by angles and distances relative to earth's body and to sky and the possible reconclusions to earth's figure and to natural moons movement. The latter beeing in a too far distance from the earth, the former surely will help to solve different problems of geodesy and astronomy. La Lune artificielle, comme projet d'une science serieuse moderne, presente, quand meme prealablement sans realite, un grand nombre de problemes theoriques interessantes. Avant tout la figure elle meme de sa route dans le champs variant de la gravite et de la force centrifuge, de plus l'observation par angles et distances relatives a la terre et au ciel, et les reconclusions a la figure de la terre et au mouvement de la Lune naturelle. Cette derniere se trouvant perpetuellement dans une position de distance trop grande, la premiere peut aider sans doute la solution de problemes differents de geodesie et astronomie.

This “personal history” covers the period from about 1954 to the present, beginning with the time that I witnessed the start of the U.S. space program triggered by the launch of Sputnik, and includes my experience as Project Scientist for Pioneers 1, 2, 5, and Explorer 6, my service at NASA headquarters as Chief of Lunar and Planetary Sciences, followed by my role in organization of the NASA Ames Space Sciences Division, and in 1973, I formed the Dept. of Planetary Sciences at the University of Arizona.

A new mechanism for lunar transient phenomena is proposed. Electrodynamic effects associated with rock fracturing seem to be able to account for sporadic optical pulses seen near certain lunar features from Earth. Only mild seismic activity or perhaps thermal cracking is required.

Modern computers enable us to obtain realistic values for the present tidal torque between the Moon and the oceans; those values agree with the observations. In principle, computations for distant geological epochs are possible as well and have been performed. However, the very complex eigenperiod spectrum of the oceans today precludes a continuous reconstruction of the tidal torque for an essential part of the Earth’s history. Hence the original state of the Earth-Moon system is still uncertain. We emphasize the importance of results for intermediate timescales.

Вычuсляеmся nрецессuонно-нуmaцuонныŭ моменm nрuлuвообрaзующuх сuл ом Луны в зaвuсuмосmu оm nосmоянных Сmоксa Землu. Выясняеmся оmношенuе uн¶rt;uвu¶rt;уaльных членов эmого моменma к nрuлuвообрaзующеŭ сuловоŭ функцuu.