Evolution of the moon: The 1974 model

Investigations are reported of Apollo and Luna explorations which have brought about the understanding of the moon and its structure. It is shown that with this knowledge of the moon, a better understanding is presented of the earth's origin, structure and composition

Evolution of the moon: The 1974 model

The interpretive evolution of the moon can be divided now into seven major stages beginning sometime near the end of the formation of the solar system. These stages and their approximate durations in time are as follows: (1) The Beginning: 4.6 billion years ago, (2) The Melted Shell: 4.6 to 4.4 billion years ago, (3) The Cratered Highlands: 4.4 to 4.1 billion years ago, (4) The Large Basins: 4.1 to 3.9 billion years ago, (5) The Light-colored Plains: 3.9 to 3.8 billion years ago, (6) The Basaltic Maria: 3.8 to 3.0(?) billion years ago, and (7) The Quiet Crust: 3.0(?) billion years ago to the present. The contributions of the Apollo and Luna exploration toward the study of those stages of evolution are reviewed

Economic geology of lunar Helium-3

Economic geology evaluation of lunar He-3 should answer the question: Can lunar He-3 be sold on Earth with sufficient profit margins and low enough risk to attract capital investment in the enterprise. Concepts that relate to economic geology of recovering He-3 from the lunar maria are not new to human experience. A parametric cost and technology evaluation scheme, based on existing and future data, is required to qualitatively and quantitatively assess the comprehensive economic feasibility and return on investment of He-3 recovery from the lunar maria. There are also many political issues which must be considered as a result of nuclear fusion and lunar mining

INTERMARS: User-controlled international management system

Existing international space law as well as the best interest of all nations are consistent with the establishment of a user-based international organization, herein called INTERMARS. INTERMARS would provide access to facilities and services at a Martian base which would be of high functional potential, quality, safety, and reliability. These opportunities would be available on an open and nondiscriminatory basis to all peaceful users and investors. INTERMARS is a model organization concept tailored to provide cooperative international management of a Martian base for the benefit of its members, users, and investors. Most importantly, INTERMARS would provide such management through a sharing of both sovereignty and opportunity rather then unilateral control by any one nation or set of competing nations. Through an Assembly of Parties, a Board of Governors, a Board of Users and Investors, and a Director General, INTERMARS would meet its primary goal as it would be in the self-interest of all members, users, and investors to do so. The internal structure and philosophy of INTERMARS would provide not only for all participants to have representation in decisions affecting its activities, but also would insure effective and responsive management. Surely this is the precedent wished for, to establish for mankind at the now not-so-distant shores of the new ocean of space

ETHICS, ECONOMICS, AND INSTITUTIONAL INNOVATIONS

Institutional and Behavioral Economics,

A closer look at semistability for singular principal bundles

We substantially refine the theory of singular principal bundles introduced in a former paper. In particular, we show that we need only honest singular principal bundles in our compactification. These are objects which carry the structure of a rational principal bundle in the sense of Ramanathan. Moreover, we arrive at a much simpler semistability condition. In the case of a semisimple group, this is just the Gieseker-version of Ramanathan's semistability condition for the corresponding rational principal $G$-bundle.Comment: To appear in the International Mathematics Research Notices. V2: Minor correction

A spatially resolved limb flare on Algol B observed with XMM-Newton

We report XMM-Newton observations of the eclipsing binary Algol A (B8V) and B (K2III). The XMM-Newton data cover the phase interval 0.35 - 0.58, i.e., specifically the time of optical secondary minimum, when the X-ray dark B-type star occults a major fraction of the X-ray bright K-type star. During the eclipse a flare was observed with complete light curve coverage. The decay part of the flare can be well described with an exponential decay law allowing a rectification of the light curve and a reconstruction of the flaring plasma region. The flare occurred near the limb of Algol B at a height of about 0.1R with plasma densities of a few times 10^11 cm^-3 consistent with spectroscopic density estimates. No eclipse of the quiescent X-ray emission is observed leading us to the conclusion that the overall coronal filling factor of Algol B is small.Comment: 8 pages, 7 figures, accepted by A&

X-ray activity cycle on the active ultra-fast rotator AB Dor A? Implication of correlated coronal and photometric variability

Although chromospheric activity cycles have been studied in a larger number of late-type stars for quite some time, very little is known about coronal activity-cycles in other stars and their similarities or dissimilarities with the solar activity cycle. While it is usually assumed that cyclic activity is present only in stars of low to moderate activity, we investigate whether the ultra-fast rotator AB Dor, a K dwarf exhibiting signs of substantial magnetic activity in essentially all wavelength bands, exhibits a X-ray activity cycle in analogy to its photospheric activity cycle of about 17 years and possible correlations between these bands. We analysed the combined optical photometric data of AB Dor A, which span ~35 years. Additionally, we used ROSAT and XMM-Newton X-ray observations of AB Dor A to study the long-term evolution of magnetic activity in this active K dwarf over nearly three decades and searched for X-ray activity cycles and related photometric brightness changes. AB Dor A exhibits photometric brightness variations ranging between 6.75 < Vmag < 7.15 while the X-ray luminosities range between 29.8 < log LX [erg/s] < 30.2 in the 0.3-2.5 keV. As a very active star, AB Dor A shows frequent X-ray flaring, but, in the long XMM-Newton observations a kind of basal state is attained very often. This basal state probably varies with the photospheric activity-cycle of AB Dor A which has a period of ~17 years, but, the X-ray variability amounts at most to a factor of ~2, which is, much lower than the typical cycle amplitudes found on the Sun.Comment: 10 page