Determination of Global Density Inhomogeneities and Stresses Inside the Moon

2020 ◽  
Vol 54 (4) ◽  
pp. 295-306
Author(s):  
N. A. Chuikova ◽  
L. P. Nasonova ◽  
T. G. Maximova
Keyword(s):  
The Moon ◽  
Density Inhomogeneities ◽  
Global Density

Automated Determination of the Position of Ships by Satellites

1967 ◽  
Vol 20 (03) ◽  
pp. 281-285
Author(s):  
H. C. Freiesleben
Keyword(s):  
Celestial Body ◽  
World Wide ◽  
Artificial Satellites ◽  
Radio Waves ◽  
The Moon ◽  
Position Determination ◽  
The Earth ◽  
Navigational Aids ◽  
Automated Determination

It has recently been suggested that 24-hour satellites might be used as navigational aids. To what category of position determination aids should these be assigned ? Is a satellite of this kind as it were a landmark, because, at least in theory, it remains fixed over the same point on the Earth's surface, in which case it should be classified under land-based navigation aids ? Is it a celestial body, although only one tenth as far from the Earth as the Moon ? If so, it is an astronomical navigation aid. Or is it a radio aid ? After all, its use for position determination depends on radio waves. In this paper I shall favour this last view. For automation is most feasible when an object of observation can be manipulated. This is easiest with radio aids, but it is, of course, impossible with natural stars.At present artificial satellites have the advantage over all other radio aids of world-wide coverage.

scholarly journals Astronomy at the service of the Islamic society

2009 ◽  
Vol 5 (S260) ◽  
pp. 514-521
Author(s):  
Ilias M. Fernini
Keyword(s):  
Proper Time ◽  
Astronomical Observatory ◽  
The Sun ◽  
The Moon ◽  
Scientific Institutions ◽  
Mathematical Astronomy ◽  
Islamic Empire ◽  
New Moon ◽  
Islamic Society

AbstractThe Islamic society has great ties to astronomy. Its main religious customs (start of the Islamic month, direction of prayer, and the five daily prayers) are all related to two main celestial objects: the Sun and the Moon. First, the start of any Islamic month is related to the actual seeing of the young crescent after the new Moon. Second, the direction of prayer, i.e., praying towards Mecca, is related to the determination of the zenith point in Mecca. Third, the proper time for the five daily prayers is related to the motion of the Sun. Everyone in the society is directly concerned by these customs. This is to say that the major impetus for the growth of Islamic astronomy came from these three main religious observances which presented an assortment of problems in mathematical astronomy. To observe these three customs, a new set of astronomical observations were needed and this helped the development of the Islamic observatory. There is a claim that it was first in Islam that the astronomical observatory came into real existence. The Islamic observatory was a product of needs and values interwoven into the Islamic society and culture. It is also considered as a true representative and an integral par of the Islamic civilisation. Since astronomy interested not only men of science, but also the rulers of the Islamic empire, several observatories have flourished. The observatories of Baghdad, Cairo, Córdoba, Toledo, Maragha, Samarqand and Istanbul acquired a worldwide reputation throughout the centuries. This paper will discuss the two most important observatories (Maragha and Samarqand) in terms of their instruments and discoveries that contributed to the establishment of these scientific institutions.

Shape of the Moon from the Orbiter Determination of its Gravitational Field

Nature ◽  
1966 ◽  
Vol 212 (5059) ◽  
pp. 271-271 ◽  
Author(s):  
C. L. GOUDAS ◽  
Z. KOPAL ◽  
Z. KOPAL
Keyword(s):  
Gravitational Field ◽  
The Moon

scholarly journals The Lunar orbit paradox

2013 ◽  
Vol 40 (1) ◽  
pp. 135-146
Author(s):  
Aleksandar Tomic
Keyword(s):  
Inertial Mass ◽  
Lunar Orbit ◽  
The Sun ◽  
The Moon ◽  
The Earth ◽  
Three Body ◽  
Origin Of The Moon ◽  
Force Intensity ◽  
Critical Consideration

Newton's formula for gravity force gives greather force intensity for atraction of the Moon by the Sun than atraction by the Earth. However, central body in lunar (primary) orbit is the Earth. So appeared paradox which were ignored from competent specialist, because the most important problem, determination of lunar orbit, was inmediately solved sufficiently by mathematical ingeniosity - introducing the Sun as dominant body in the three body system by Delaunay, 1860. On this way the lunar orbit paradox were not canceled. Vujicic made a owerview of principles of mechanics in year 1998, in critical consideration. As an example for application of corrected procedure he was obtained gravity law in some different form, which gave possibility to cancel paradox of lunar orbit. The formula of Vujicic, with our small adaptation, content two type of acceleration - related to inertial mass and related to gravity mass. So appears carried information on the origin of the Moon, and paradox cancels.

scholarly journals Commission 19: Rotation of the Earth

1985 ◽  
Vol 19 (1) ◽  
pp. 193-205 ◽  
Author(s):  
Ya. S. Yatskiv ◽  
W. J. Klepczynski ◽  
F. Barlier ◽  
H. Enslin ◽  
C. Kakuta ◽  
...  
Keyword(s):  
Time Frame ◽  
Laser Ranging ◽  
Earth’S Rotation ◽  
The Moon ◽  
Earth's Rotation ◽  
The Earth ◽  
Long Time ◽  
Terrestrial Reference System ◽  
Rotation Of The Earth

During the period, work on the problem of the Earth’s rotation has continued to expand and increase its scope. The total number of institutions engaged in the determination of the Earth’s rotation parameters (ERP) by different techniques has been increased significantly. The rotation of the Earth is currently measured by classical astrometry, Doppler and laser satellite tracking, laser ranging of the Moon, and radio interferometry. Several long time series of the ERP are available from most of these techniques, in particular, those made during the Main Campaign of the MERIT project. The various series have been intercompared and their stability, in the time frame of years to days, has been estimated for the purposes of establishing a new conventional terrestrial reference system (COTES). On the other hand, the difficulties of maintaining a regular operation for laser ranging to the Moon (LLR) have been recognized. It resulted in the proposal to organize an one-month campaign of observations in 1985 in order to complement the COTES collocation program and to allow additional intercomparisons with other techniques.

Rocket Determination of the Ultra-Violet Reflectivity of the Moon

1967 ◽  
Vol 1 (1) ◽  
pp. 11-11 ◽  
Author(s):  
J. H. Carver ◽  
B. H. Horton
Keyword(s):  
Wavelength Range ◽  
Full Moon ◽  
Ultra Violet ◽  
Lunar Phase ◽  
Atmospheric Ozone ◽  
The Moon

We have used rocket-borne photometers to determine the ultra-violet flux of the full moon in the wavelength range 2400-2900A where atmospheric ozone prevents ground-based observations. The lunar fluxes determined in two rocket firings from Woomera on 9th December, 1965, and 30th August, 1966, are summarized in the Table. The results for the two firings have been corrected to full moon values on the assumption that the lunar phase law is the same at these ultra-violet wavelengths as it is in the visible.

scholarly journals The Shape of the Moon

1972 ◽  
Vol 47 ◽  
pp. 22-31 ◽  
Author(s):  
S. K. Runcorn ◽  
S. Hofmann
Keyword(s):  
Lunar Surface ◽  
Major Axis ◽  
Great Depth ◽  
The Moon ◽  
Method Of Least Squares ◽  
Global Shape ◽  
The Earth ◽  
Intrinsic Scatter ◽  
Simple Statistical Analysis

The determination of the heights of points on the lunar surface by Earth based astronomy using the geometrical librations, although individually of low accuracy, still provides our best method of obtaining the global shape of the Moon. The intrinsic scatter of the results arises from the effects of ‘seeing’ and simple statistical analysis is required to derive valid conclusions about the shape. Baldwin's method of fitting ellipsoidal surfaces to the points on the maria and uplands, separately by the method of least squares proves to be a valuable tool.Analyses of the ACIC points and of the Pic du Midi studies of G. A. Mills show that good first descriptions of the global shape of the Moon for both the maria and uplands are triaxial ellipsoids with their long axes within 10° of the Earth direction, the major axis of the maria being about 1.3 km smaller than that of the uplands. Of particular significance is that the ellipticity of these surfaces is about 2½ times greater than the dynamical ellipticity; thus the non-hydrostatic figure of the Moon is not simply the result of distortion from a uniform Moon during its early history. The angular variation in density within the Moon cannot be simply a phenomena within the crust but must extend to a great depth. Convection could provide an explanation.The departures of the lunar surface from the idealised ellipsoids are also of interest. The circular maria are systematically depressed relative to the maria ellipsoid: can the mascons have adjusted isostatically since their formation? Systematic differences in height between the western and eastern southern uplands are also noted.

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