scholarly journals Measurements of the gravitational constant and of the mean specific mass of the Earth

1900 ◽  
Vol 029 (1) ◽  
pp. 10-28
Author(s):  
Vladimír Novák
Keyword(s):  
Gravitational Constant ◽  
Specific Mass ◽  
The Earth ◽  
The Mean

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

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.

scholarly journals Some Special Types of Orbits around Jupiter

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 183
Author(s):  
Yongjie Liu ◽  
Yu Jiang ◽  
Hengnian Li ◽  
Hui Zhang
Keyword(s):  
Gravity Model ◽  
Small Perturbation ◽  
Equilibrium Points ◽  
Major Axis ◽  
Semi Major Axis ◽  
Ground Track ◽  
The Earth ◽  
Degenerate Equilibrium ◽  
The Mean ◽  
Element Theory

This paper intends to show some special types of orbits around Jupiter based on the mean element theory, including stationary orbits, sun-synchronous orbits, orbits at the critical inclination, and repeating ground track orbits. A gravity model concerning only the perturbations of J2 and J4 terms is used here. Compared with special orbits around the Earth, the orbit dynamics differ greatly: (1) There do not exist longitude drifts on stationary orbits due to non-spherical gravity since only J2 and J4 terms are taken into account in the gravity model. All points on stationary orbits are degenerate equilibrium points. Moreover, the satellite will oscillate in the radial and North-South directions after a sufficiently small perturbation of stationary orbits. (2) The inclinations of sun-synchronous orbits are always bigger than 90 degrees, but smaller than those for satellites around the Earth. (3) The critical inclinations are no-longer independent of the semi-major axis and eccentricity of the orbits. The results show that if the eccentricity is small, the critical inclinations will decrease as the altitudes of orbits increase; if the eccentricity is larger, the critical inclinations will increase as the altitudes of orbits increase. (4) The inclinations of repeating ground track orbits are monotonically increasing rapidly with respect to the altitudes of orbits.

The density variation of the earth's central core*

1942 ◽  
Vol 32 (1) ◽  
pp. 19-29
Author(s):  
K. E. Bullen
Keyword(s):  
Pure Iron ◽  
Outer Boundary ◽  
Density Variation ◽  
Central Core ◽  
Good Precision ◽  
Wide Margin ◽  
The Core ◽  
The Earth ◽  
The Mean ◽  
Published Paper

ABSTRACT A detailed analysis of the problem of the earth's density variation has been extended to the earth's central core. It is shown that in the region between the outer boundary of the core and a distance of about 1400 km. from the earth's center the density ranges from 9.4 gm/cm.3 to 11.5 gm/cm.3 within an uncertainty which, if certain general assumptions are true, does not exceed 3 per cent. The density and pressure figures are, moreover, compatible with the existence of fairly pure iron in this part of the earth. The result for the earth's outer mantle as given in a previously published paper, together with those in the present paper, are found to give with good precision the density distribution in a region occupying 99 per cent of the earth's volume. Values of the density within 1400 km. of the earth's center are subject, however, to a wide margin of uncertainty, and there appears to be no means of resolving this uncertainty for the present. The most that can be said is that the mean density in the latter region is greater than 12.3 gm/cm.3 and may quite possibly be several gm/cm.3 in excess of this figure. In the present paper figures are also included for the variation of gravity and the distribution of pressure within the central core. The gravity results are shown to be subject to an appreciable uncertainty except within about 1000 km. of the outer boundary of the core, but the pressure results are expected to be closely accurate at all depths.

scholarly journals XII. On the cause of the discrepancies observed by Mr. Baily with the Cavendish apparatus for determining the mean density of the earth

1847 ◽  
Vol 137 ◽  
pp. 217-229 ◽  
Keyword(s):  
Mathematical Theory ◽  
Full Account ◽  
Astronomical Society ◽  
Royal Astronomical Society ◽  
The Earth ◽  
Singular Source ◽  
The Mean ◽  
The Masses ◽  
Source Of Error ◽  
Different Parts

In the Fourteenth Volume of the Transactions of the Royal Astronomical Society will be found a full account of the Cavendish apparatus, and of the mode of experimenting followed by Mr. Baily. It will therefore not be necessary for me, in this place, to enter into any detail as to the different parts of the instrument, and the various precautions adopted in order to avoid that singular source of error 'currents of air in the torsion box arising from unequal temperature,’ which had been discovered by Cavendish. It will be sufficient for me to state that all the arrangements are of a highly satisfactory kind, and that I am of opinion that no aerial currents could have existed in the torsion box. The deduction of the mean density of the earth from the observed vibrations of the balls influenced by the torsion force and the attraction of the masses, is founded on a mathematical theory of the motion of the balls given by the Astronomer Royal, Mr. Airy ; and as this theory is certainly insufficient to account for the discrepancies, it will here be necessary to give a brief sketch of it.

Bioclimate of Jericho in Palestine

2019 ◽  
Vol 7 (1) ◽  
pp. 1-7
Author(s):  
Jehad Ighbareyeh
Keyword(s):  
Minimum Temperature ◽  
Thermal Model ◽  
Arid Regions ◽  
Dead Sea ◽  
Maximum Temperature ◽  
Stone Age ◽  
The Earth ◽  
Latitudinal Belt ◽  
The Mean ◽  
Very High

 Jericho is an ancient Canaanite Palestinian city and one of the oldest cities in history, which dates back to more than 10.000 BC (Stone Age). It is located near to the Jordan River, north of the Dead Sea, and north of Jerusalem. Moreover, it considered the lowest area in the earth and has a unique climatic zone. during the study period (1975-1995), was utilized the Salvador Rivas Martinez scale to classify the bioclimate of the earth to analysis the climate and bioclimate data, which was obtained from one station from Palestinian Meteorology Department (Jericho station). The results revealed that the mean monthly temperature was 22.4 0C, mean maximum temperature was 34.8 0C, mean monthly minimum temperature was 15.3 0C, the value of the annual ombrothermic index was 0.6, the compensated thermicity index is very high around 1209/1209 and the simple continentality index was 16.7. The bioclomate of Jericho is located within the zones of the thermal model under the inframediterranean basin, the dry and arid regions. Jericho is belong to Mediterranean desertic-oceanic, the latitudinal belt as subtropical, while continentality is oceanic-low eu-oceanic.

VII.—The Dynamics of Cyclones and Anticyclones. Part III

1916 ◽  
Vol 36 (1-2) ◽  
pp. 174-185
Author(s):  
John Aitken
Keyword(s):  
Water Vapour ◽  
Atmospheric Circulation ◽  
Moist Air ◽  
The Earth ◽  
Isothermal Layer ◽  
New Knowledge ◽  
The Mean

In 1900 I communicated to this Society a paper on the above subject. Since that date a great deal of information has been obtained by means of free balloons carrying instruments which recorded the temperature, humidity, and pressure of the air up to great elevations. Much of this new knowledge seems to contradict our previous ideas, and does not seem to fit into the old convectional theory that cyclones are formed by the rising of the hot, moist air from the surface of the earth; their energy being due to their temperature and to the heat liberated by the condensation of the water vapour in them. We are told by those who have studied the bearing of the new knowledge on our atmospheric circulation that the old theory is “utterly untenable.” Their reasons for this conclusion are, first, that the recent investigations show that the air is colder in cyclones than in anticyclones; second, that the isothermal layer is lower than the mean over cyclones, while it is higher than the mean over anticyclones. At first sight these discoveries seem to shatter the convectional theory, but before we come to any conclusion I should like to present certain facts which it appears to me will require to be considered before we scrap our old ideas.

scholarly journals XIV. On a determination of the mean density of the Earth and the gravitation constant by means of the common balance

1891 ◽  
Vol 182 ◽  
pp. 565-656 ◽  
Keyword(s):  
Royal Society ◽  
Torsion Balance ◽  
Chemical Balance ◽  
The Earth ◽  
The Common ◽  
The Mean ◽  
Common Balance

In a paper printed in the Proceedings of the Royal Society,' No. 190, 1878 (vol. 28, pp. 2-35), I gave an account of some experiments undertaken in order to test the possibility of using the Common Balance in place of the Torsion Balance in the Cavendish Experiment. The success obtained seemed to justify the intention expressed in that paper to continue the work, using a large bullion balance, instead of the chemical balance with which the preliminary experiments were made. As I have had the honour to obtain grants from the Royal Society for the construction of the necessary apparatus, I have been able to carry out the experiment on the larger scale which appeared likely to render the method more satisfactory, and this paper contains an account of the results obtained.

The Mean Density of the Earth

Nature ◽  
1894 ◽  
Vol 50 (1301) ◽  
pp. 542-543
Keyword(s):  
The Earth ◽  
The Mean
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