For the Moon

The age estimate for the moon is similar to age estimates for the Earth based on several methods of radioactive dating. Thus, this is a sensible result. 

From here there s little indication of the passing of time, except for the moon-drawn rise and fall of the river. At low tide there are a few yards of rubbish-strewn shingle at high tide the water runs perhaps six feet below my study window. Rotherhithe on the far bank is too distant to be real we watched what was renamed Docklands as one might a strange colony of insects. 

Except for the moon and the planet Mars, no extraterrestrial body has had pieces of its mass directly examined by scientists in an earthly laboratory. This means that there has been no laboratory sample preparation scheme performed on samples of solid matter from any of the other planets, their moons, comets, or asteroids. And yet we read repeatedly about how scientists have been able to surmise the... 

Fulgentio was still protesting about grass as I dragged him and Giorgio downstairs. I had wrapped myself in my winter cloak and, needless to say, we wore our swords and daggers. We took an armful of torches, for the moon had already set behind the rooftops. 

What would be nice is a development that enabled us make in advance, an estimate of the sort of en or that there mi t be in a particular property when using a particular approach. Now I certainly don t hope for the moon here. I don t expect a rigorous variational result or even a perturbation estimate. Rather I hope for the sort of knowledge that, for exfunple, makes us confident of a particular outcome for properties calculated using an LCAO-... 

Comparison of the abundances of volatile and refractory elements, normalized to Cl chondrites, for the Moon and the Earth. After Taylor et al. (2006a). 

Incomplete recondensation of vaporized materials could also account for the Moon s depletion in volatiles and its virtual absence of water. 

Planets, satellites, and small bodies provide a wide range of dynamical and chemical constraints on the building of the Solar System from planetesimals. In addition to the primary parameters of planets, the planet mass and semi-major axis distributions, the relative masses of the cores (exceptionally large for Mercury and low for the Moon) provide further constraints. In addition, the Asteroid Belt seems to be depleted in mass by three to four orders of magnitude and its medium- to small-sized... 

Among other facts, the difference in the FeO/MnO ratio for the Moon and for the Earth rules out the possibility that the Moon was once part of the Earth.100 ... 

Fig. 14 includes terrestrial and meteoritic samples which show that the good correlation of La and K is not restricted to the Moon. It is interesting to note that the correlation line for the Moon falls close to that of the basaltic achondrites and that furthermore the silicate phases of mesosiderites and the hypersthene chondrite (diogenite) Johnstown fall on the line of the basaltic achondrites. 

We have convincing evidence that this high-temperature component (HTC) is responsible for the enrichment of the refractory elements, both for the Moon and the basaltic achondrites, in spite of the fact that the absolute percentage of the HTC is somewhat different. 

Nb decays by electron capture to Zr with a half-life of 36 3 Myr. At one time it was thought to offer the potential to obtain an age for the Moon by dating early lunar Umenites and the formation of Umenite-rich layers in the lunar mantle. Others proposed that it provided constraints on the time-scales for the earhest formation of continents on Earth (Miinker et al, 2000). In addition, it was argued that it would date terrestrial core formation (Jacobsen and Yin, 2001). There have been many attempts to utilize this isotopic system over the past few years. To do so, it is necessary to first determine the initial Nb abundance in early solar system objects accurately and various authors have made claims that differ by two orders of magnitude. 

As accurately as these calculations can be made, however, the behavior of celestial bodies over long periods of time cannot always be determined. For example, the perturbation method has so far been unable to determine the stability either of the orbits of individual bodies or of the solar system as a whole for the estimated age of the solar system. Studies of the evolution of the Earth-Moon system indicate that the Moon s orbit may become unstable, which will make it possible for the Moon to escape into an independent orbit around the Sun. Recent astronomers have also used the theory of chaos to explain irregular orbits. 

Named after Selene, the Greek name for the moon, selenium was isolated by Jakob Berzelius (1779-1848) in 1817. Because its properties were similar to those of tellurium (named after the Earth), Berzelius named it after the moon. Selenium is rare and never occurs in elemental form. It is used in photocopiers, electronic components, and glassmaking and as an additive in specialty stainless steel. 

Se selenium, 34, 1818 named for the moon ( selene in Greek) because of its resemblance to tellurium, which was named for the earth. 

These corrections are large for the terrestrial bodies with the largest masses and internal pressures, Venus and Earth, and smallest for the Moon and Mercury. Note that making precise corrections requires some prior knowledge of the compressibility, and hence the mineralogy and structure, of the interior. These estimates assume that the same basic minerals (Fe-Ni, FeS, and silicates) are present in each body and that all are fully differentiated. 

To date, there exists very little quantitative information concerning oxygen isotope compositions in major solar system reservoirs that is obtained by remote (spectroscopic) observation or spacecraft measurements. A measurement of water ice from comet P/Halley, made by the Giotto mission, yields = 12 75 %o (Balsiger et al. 1995 Eberhardt et al. 1995) but no measurement of is available. Precise data are obtained for the Moon, of course, from returned Apollo samples, and the oxygen isotope composition of Mars and the largest asteroid, Vesta, may be inferred from laboratory... 

SCR protons and alpha-particles penetrate only a very few cm into solid matter. Therefore, SCR-produced cosmogenic nuclides are normally not expected to be observed in meteorites, because their outermost few cm usually were ablated in the Earth s atmosphere. SCR nuclide concentration profiles therefore mostly have been calculated for the Moon, i.e., for samples with lunar chemical composition irradiated at 1 AU from the Sun. Most of the recent work has been done by R.C. Reedy and coworkers (e.g., Rao et al. 1994 Reedy 1998a,b) and R. Michel and coworkers (Michel et al. 1996 Neumann... 

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