نتایج جستجو برای: moon
تعداد نتایج: 9039 فیلتر نتایج به سال:
The lunar magma ocean: Reconciling the solidification process with lunar petrology and geochronology
Estimates of the chemical composition of the bulk (entire) Moon fall into two drastically different categories. One group of estimates claims that the Moon is enriched in refractory elements (those that boil at high temperatures, such as calcium and aluminum) by about 50% compared to Earth. The other group claims that the abundances of refractory elements are the same in the Earth and Moon. Two...
Most gymnosperms are wind-pollinated, but some are insect-pollinated, and in Ephedra (Gnetales), both wind pollination and insect pollination occur. Little is, however, known about mechanisms and evolution of pollination syndromes in gymnosperms. Based on four seasons of field studies, we show an unexpected correlation between pollination and the phases of the moon in one of our studied species...
We use the GEANT4 Monte Carlo framework to calculate the γ-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of γ-rays from the Moon is very steep with an effective cutoff around 4 GeV (600 MeV for the inner part of the Moon disc). Apart from other astrophysical source...
Popular belief holds that the lunar cycle affects human physiology, behaviour and health. We examined the influence of moon phase on sleep duration in a secondary analysis of a feasibility study of mobile telephone base stations and sleep quality. We studied 31 volunteers (18 women and 13 men, mean age 50 years) from a suburban area of Switzerland longitudinally over 6 weeks, including two full...
The Earth-Moon system has often been characterized as having some characteristics of a “double planet” system. It is demonstrated that while the orbital barycenter of the Earth-Moon pair lies inside the radius of the Earth, the Moon does meet all three requirements of the IAU definition for “planet” and therefore the Moon can correctly be identified as the Solar System’s 9 planet. In order to a...
In this paper we consider the existence of stable motions for a particle near the triangular points of the Earth-Moon system. To this end, we first use a simplified model (the socalled Bicircular Problem, BCP) that includes the main effects coming from the Earth, Moon and Sun. The neighbourhood of the triangular points in the BCP model is unstable, as happens in the real system. However, here w...
The hypothesis of lunar origin by a single giant impact can explain some aspects of the Earth–Moon system. However, it is di cult to reconcile giant-impact models with the compositional similarity of the Earth and Moon without violating angular momentum constraints. Furthermore, successful giant-impact scenarios require very specific conditions such that they have a low probability of occurring...
In this paper the problem of sending a spacecraft from Low Earth Orbit (LEO) to the Moon with minimum fuel consumption is considered. It is assumed that the "Two-Body model" approximation is valid in all phases of the mission and that the final orbit around the Moon is polar. The first part deals with impulsive maneuvers, and obtain a set of values for fuel expenditure and trip time for several...
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