scholarly journals Welt Mechanik

The object which the author has in view, in this paper, is to over­turn the theory of universal gravitation, as regulating the planetary motions. The memoir is divided into two parts ; in the first, he dis­putes the accuracy of Kepler’s law respecting the description of equal areas in equal times, and endeavours to confute the funda­mental doctrines of astronomy relating to the elliptical orbit of the earth, the difference between solar and mean time, and the whole theory of the motions of the moon and the planets. In the second part, the author enters into a detailed exposition of his own views of the mechanism of the heavens ; and devotes 215 closely' written pages to the development of a perfectly new hypothesis, which he advances, founded on a supposed variation of the progressive mo­tion of the planets, in an orbit perfectly circular, and by which he thinks he can explain all the phenomena they present to observa­tion.

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.


There is a memorandum in Newton’s handwriting among the papers which formed the Portsmouth collection which has often been quoted. It was probably written in 1716, when Newton was seventy-three years old. One passage, in particular, I am sure you will remember: In the same year I began to think o f gravity extending to the orb of the Moon, and having found out how to estimate the force with which a globe revolving within a sphere presses the surface of the sphere, from Kepler’s rule of the periodical times of the Planets being in a sesquialterate proportion of their distances from the centres of their orbs I deduced that the forces which keep the Planets in their orbs must be reciprocally as the squares of their distances from the centres about which they revolve: and thereby compared the force requisite to keep the Moon in her orb with the force of gravity at the surface of the Earth, and found them answer pretty nearly. Thus Newton, in old age, undeterred by the inadequacy of ordinary language fully to expose the springs of his inspiration, set out soberly, and in logical order, the steps by which the hypothesis of universal gravitation formed in his mind and came to carry conviction.


2020 ◽  
Vol 2 (1) ◽  
pp. 34
Author(s):  
Wasudewa Bhattacarya

<p><em>The spread of Hinduism from India to Indonesia is the result of acculturation of culture which then brought the concepts of Astronomy-Astrology in </em><em>Jyotiṣa </em><em>to Indonesia and Bali. Arriving in Bali, the concept of Astronomy-Astrology is known as Wariga. Wariga’s existence gave rise to holy days in the implementation of Yajña. One of them is the holy day of Purnama-Tilem. The determination of this holy day is based on the appearance of the moon from the earth as a repetitive cycle. If the moon appears perfectly round from the earth, it is called Purnama (Full Moon), whereas if the moon is not visible from the earth it is called Tilem (Dark Moon). This shows that there are two very basic differences in  determining Purnama  and  Tilem.  Dualistic this difference in Hinduism is called Rwa Bhinneda. Rwa Binneda is a polarization of life that speaks of all forms of dualism such as, top down, right left, dark light, and so on. Based on manuscipts in Bali, the existence of Purnama and Tilem shows a dualism in Hindu Theology called Sanghyang Rwa Bhinneda there  are Sanghyang Wulan and Sanghyang Surya at the level of </em><em>Saguṇa </em><em>Brahman. The dualism of the difference between Purnama and Tilem also influences Bhuwana Agung and Bhuwana Alit. The difference in the meaning of Purnama and Tilem is not something bad, but through this difference will bring about a balance between God, humans and the universe so that all beings will be able to reach the Moksartham Jagadhita ya ca iti Dharma.</em><em></em></p><p><strong><em><br /></em></strong><em></em><em></em></p>


2021 ◽  
Vol 366 (7) ◽  
Author(s):  
Neus Puchades Colmenero ◽  
José Vicente Arnau Córdoba ◽  
Màrius Josep Fullana i Alfonso

AbstractUncertainties in the satellite world lines lead to dominant positioning errors. In the present work, using the approach presented in Puchades and Sáez (Astrophys. Space Sci. 352, 307–320, 2014), a new analysis of these errors is developed inside a great region surrounding Earth. This analysis is performed in the framework of the so-called Relativistic Positioning Systems (RPS). Schwarzschild metric is used to describe the satellite orbits corresponding to the Galileo Satellites Constellation. Those orbits are circular with the Earth as their centre. They are defined as the nominal orbits. The satellite orbits are not circular due to the perturbations they have and to achieve a more realistic description such perturbations need to be taken into account. In Puchades and Sáez (Astrophys. Space Sci. 352, 307–320, 2014) perturbations of the nominal orbits were statistically simulated. Using the formula from Coll et al. (Class. Quantum Gravity. 27, 065013, 2010) a user location is determined with the four satellites proper times that the user receives and with the satellite world lines. This formula can be used with any satellite description, although photons need to travel in a Minkowskian space-time. For our purposes, the computation of the photon geodesics in Minkowski space-time is sufficient as demonstrated in Puchades and Sáez (Adv. Space Res. 57, 499–508, 2016). The difference of the user position determined with the nominal and the perturbed satellite orbits is computed. This difference is defined as the U-error. Now we compute the perturbed orbits of the satellites considering a metric that takes into account the gravitational effects of the Earth, the Moon and the Sun and also the Earth oblateness. A study of the satellite orbits in this new metric is first introduced. Then we compute the U-errors comparing the positions given with the Schwarzschild metric and the metric introduced here. A Runge-Kutta method is used to solve the satellite geodesic equations. Some improvements in the computation of the U-errors using both metrics are introduced with respect to our previous works. Conclusions and perspectives are also presented.


2014 ◽  
Vol 9 (S310) ◽  
pp. 45-48
Author(s):  
A. Shuvalova ◽  
T. Salnikova

AbstractIn this paper we consider the special case of the planar circular restricted three-body problem by the example of the problem of the Earth, the Moon and a point mass, where the gravitational potentials of the Earth and the Moon are given as the Kislik potential. The Kislik potential takes into account the flattening of a celestial body on the poles. We find the relative equilibria solutions for a point mass and analyze their stability. We describe the difference between the obtained points and the classical solution of the three-body problem.


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. 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.


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