scholarly journals Life among the Craters

2004 ◽  
Vol 213 ◽  
pp. 199-202
Author(s):  
Harrison H. Schmitt

The Moon forms one end-member in the planetary mass series Earth-Venus-Mars-Mercury-Asteroids-Moon (Weissman 1999). Having a detailed understanding of the nature and evolution of the two end-members of this series, rather than of just the Earth, has increased the value of other data and inferences by orders of magnitude. As a consequence of obtaining an understanding of the evolution of a second planet, we now can look at other terrestrial planets with far greater insight than ever would have been possible otherwise (Fig. 1).

2018 ◽  
Vol 14 (S345) ◽  
pp. 164-167
Author(s):  
Mikhail Ya. Marov ◽  
Sergei I. Ipatov

AbstractComputer simulations of migration of planetesimals from beyond the Jupiter’s orbit to the terrestrial planets have been made. Based on obtained arrays of orbital elements of planetesimals and planets during the dynamical lifetimes of planetesimals, we calculated the probabilities of collisions of planetesimals with planets, the Moon, and their embryos. The results of calculations showed that for the total mass of planetesimals of about 200 Earth masses, the mass of water delivered to the Earth from beyond the orbit of Jupiter could be about the mass of the terrestrial oceans. For the growth of the mass of the Earth embryo up to a half of the present mass of the Earth, the mass of water delivered to the embryo could be up to 30% of all water delivered to the Earth from the zone of Jupiter and Saturn. The water of the terrestrial oceans and its D/H ratio could be the result of mixing of water from several exogenic and endogenic sources with large and low D/H ratios. The ratio of the mass of water delivered from beyond the orbit of Jupiter to a planet to the mass of the planet for Venus, Mars, and Mercury was not smaller than that for the Earth. The mass of water in planetesimals that collided the Moon and migrated from beyond the Jupiter’s orbit could be not more than 20 times smaller than that for the Earth.


2019 ◽  
pp. 61-77
Author(s):  
V. N. Zharkov ◽  
T. V. Gudkova

The review of the studies on comparative planetology carried out in the Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences is presented. The obtained results are described in accordance with the study objects: the Moon, terrestrial planets, Venus and Mars, Phobos and Deimos-moons of Mars, giant planets and their moons.


1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.


1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.


1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.


1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.


1962 ◽  
Vol 14 ◽  
pp. 39-44
Author(s):  
A. V. Markov

Notwithstanding the fact that a number of defects and distortions, introduced in transmission of the images of the latter to the Earth, mar the negatives of the reverse side of the Moon, indirectly obtained on 7 October 1959 by the automatic interplanetary station (AIS), it was possible to use the photometric measurements of the secondary (terrestrial) positives of the reverse side of the Moon in the experiment of the first comparison of the characteristics of the surfaces of the visible and invisible hemispheres of the Moon.


2000 ◽  
Vol 6 (1) ◽  
pp. 56-63
Author(s):  
K.K. Kamensky ◽  
V.S. Kislyuk ◽  
Ya.S. Yatskiv ◽  
◽  

Author(s):  
Karel Schrijver

In this chapter, the author summarizes the properties of the Solar System, and how these were uncovered. Over centuries, the arrangement and properties of the Solar System were determined. The distinctions between the terrestrial planets, the gas and ice giants, and their various moons are discussed. Whereas humans have walked only on the Moon, probes have visited all the planets and several moons, asteroids, and comets; samples have been returned to Earth only from our moon, a comet, and from interplanetary dust. For Earth and Moon, seismographs probed their interior, whereas for other planets insights come from spacecraft and meteorites. We learned that elements separated between planet cores and mantels because larger bodies in the Solar System were once liquid, and many still are. How water ended up where it is presents a complex puzzle. Will the characteristics of our Solar System hold true for planetary systems in general?


Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Pyrrhon Amathes ◽  
Paul Christodoulides

Photography can be used for pleasure and art but can also be used in many disciplines of science, because it captures the details of the moment and can serve as a proving tool due to the information it preserves. During the period of the Apollo program (1969 to 1972), the National Aeronautics and Space Administration (NASA) successfully landed humans on the Moon and showed hundreds of photos to the world presenting the travel and landings. This paper uses computer simulations and geometry to examine the authenticity of one such photo, namely Apollo 17 photo GPN-2000-00113. In addition, a novel approach is employed by creating an experimental scene to illustrate details and provide measurements. The crucial factors on which the geometrical analysis relies are locked in the photograph and are: (a) the apparent position of the Earth relative to the illustrated flag and (b) the point to which the shadow of the astronaut taking the photo reaches, in relation to the flagpole. The analysis and experimental data show geometrical and time mismatches, proving that the photo is a composite.


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