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We present the first redundant detection of sporadic impact flashes on the Moon from a systematic survey performed between 2001 and 2004. Our wide-field lunar monitoring allows us to estimate the impact rate of large meteoroids on the Moon as a function of the luminous energy received on Earth. It also shows that some historical well-documented mysterious lunar events fit in a clear impact context...
Reanalysis of lunar seismic data collected during the Apollo program indicates that 23 of the 28 rare events known as high-frequency teleseismic (HFT) events or shallow moonquakes occurred during one-half of the sidereal month when the seismic network on the Moon's near side faced approximately towards right ascension of 12 h on the celestial sphere. Statistical analysis demonstrates that there is...
The contribution of a satellite in the precession motion of the axis of an oblate planet has been previously studied in the approximation of a distant satellite, or in the approximation of a very close satellite. Here we study the general problem for an arbitrary semimajor axis for the satellite, without performing the usual gyroscopic approximation. We present precessional equations valid in a very...
The large, fresh crater Tycho in the nearside lunar highlands has an extensive system of bright rays covering approximately 560,000 km 2 , containing dense clusters of secondary craters. Examination of crater densities in several clusters shows that Tycho produced almost 10 6 secondary craters larger than 63 m diameter. This is a lower limit, because small crater densities are reduced,...
The strong hydrogen signal that the Lunar Prospector saw at the Moon's poles suggests that water ice may be present near the surface of the lunar regolith. A robotic mission to obtain in situ samples and to quantify the amount of this valuable resource must be designed carefully to avoid dissipating too much heat in the regolith during coring or drilling and, thus, causing the ice to sublimate before...
The equilibrium tide-generating forces in the lunar orbital plane of a planet of radius R are calculated for the case of N moons of mass Mi orbiting the planet at instantaneous polar coordinates (Di, αi). For the case of a single moon, there are only two high tides. For the case of two moons, it is found that there can exist a critical lunar orbital distance at which two high tides become unstable...
In this study we examine a set of lunar mare domes located in the Hortensius/Milichius/T. Mayer region and in northern Mare Tranquillitatis with respect to their formation along crustal fractures, their rheologic properties, the dimensions of their feeder dikes, and the importance of magma evolution processes during dome formation. Many of these domes display elongated summit vents oriented radially...
The stability of an additional planet between the orbit of Mars and the asteroid belt is examined in the context of the Planet V hypothesis. In this model, the Solar System initially contained a fifth terrestrial planet, “Planet V,” which was removed after ∼700 Myr, a possible trigger for the late heavy bombardment on the inner planets. The model is investigated using 96 N-body integrations of the...
A late Eocene asteroid shower to the Earth–Moon system resulted in an increased flux of impact ejected 3 He-rich lunar matter to Earth, which is recorded by a 2 Ma enduring 3 He-anomaly in marine sediments.
We have extended our Monte Carlo model of exospheres [Wurz, P., Lammer, H., 2003. Icarus 164 (1), 1–13] by treating the ion-induced sputtering process from a known surface in a self-consistent way. The comparison of the calculated exospheric densities with experimental data, which are mostly upper limits, shows that all of our calculated densities are within the measurement limits. The total calculated...
A new method is presented for estimating crustal thickness from gravity and topography data on the Moon. By calculating analytically the exterior gravitational field for a set of arbitrarily shaped polyhedra, relief along the crust–mantle interface can be inverted for that satisfies the observational constraints. As this method does not rely upon filtering the Bouguer anomaly, which was required with...
3D simulations of basin-scale lunar impacts are carried out to investigate: (a) the origins of strong crustal magnetic fields and unusual terrain observed to occur in regions antipodal to young large basins; and (b) the origin of enhanced magnetic and geochemical anomalies along the northwest periphery of the South Pole-Aitken (SPA) basin. The simulations demonstrate that a basin-forming impact produces...
In the restricted circular three-body problem, two massive bodies travel on circular orbits about their mutual center of mass and gravitationally perturb the motion of a massless particle. The triangular Lagrange points, L4 and L5, form equilateral triangles with the two massive bodies and lie in their orbital plane. Provided the primary is at least 27 times as massive as the secondary, orbits near...
Prior models of lunar-forming impacts assume that both the impactor and the target protoearth were not rotating prior to the Moon-forming event. However, planet formation models suggest that such objects would have been rotating rapidly during the late stages of terrestrial accretion. In this paper I explore the effects of pre-impact rotation on impact outcomes through more than 100 hydrodynamical...
This paper presents an updated stratigraphical and compositional study of the exposed maria within the Imbrium basin on the Moon. Clementine multispectral data were employed to derive TiO 2 and FeO wt% abundance estimates of potentially distinct basaltic flows. Additionally, NASA Lunar Orbiter images were used to estimate flow ages using crater count statistics. Mare Imbrium shows evidence...
Combining UVVIS and NIR Clementine spectral data, we characterize the mineralogy of the different volcanic and crustal materials occurring on the Aristarchus Plateau and its close vicinity, in order to investigate their stratigraphic relationships and understand the nature of the crust in this region of the Moon. From an iterative linear mixture modeling, we provide a comprehensive description of...
New W isotope data for ferroan anorthosites 60025 and 62255 and low-Ti mare basalt 15555 show that these samples, contrary to previous reports [Lee, D.C., et al., 1997. Science 278, 1098–1103; Lee, D.C., et al., 2002. Earth Planet. Sci. Lett. 198, 267–274], have a W isotope composition that is indistinguishable from KREEP and other mare basalts. This requires crust extraction on the Moon later than...
Multiple large impact basins on the lunar nearside formed in a relatively-short interval around 3.8–3.9 Gyr ago, in what is known as the Lunar Cataclysm (LC; also known as Late Heavy Bombardment). It is widely thought that this impact bombardment has affected the whole Solar System or at least all the inner planets. But with non-lunar evidence for the cataclysm being relatively weak, a geocentric...
The Moon is currently locked in a spin–orbit resonance of synchronous rotation, of which one consequence is that more impacts should occur near the Moon's apex of motion (0° N, 90° W) than near its antapex of motion (0° N, 90° E). Several of the largest lunar impact basins could have temporarily unlocked the Moon from synchronous rotation, and after the re-establishment of this state the Moon would...
This study examines a set of lunar domes with very low flank slopes which differ in several respects from the frequently occurring lunar effusive domes. Some of these domes are exceptionally large, and most of them are associated with faults or linear rilles of presumably tensional origin. Accordingly, they might be interpreted as surface manifestations of laccolithic intrusions formed by flexure-induced...
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