Chemical composition of the Moon's 'primary' crust – a clue at a terrestrial origin

2020 ◽  
Author(s):  
Audrey Vorburger ◽  
Peter Wurz ◽  
Manuel Scherf ◽  
Helmut Lammer ◽  
André Galli ◽  
...  
Keyword(s):  
Lunar Surface ◽  
Major Elements ◽  
The Moon ◽  
Lunar Crust ◽  
Near Surface ◽  
Origin And Evolution ◽  
The Past ◽  
The Earth ◽  
Terrestrial Origin ◽  
In The Beginning

<p>The Moon is one of the best characterized objects in space science, yet its origin still actively researched. Available orbital, geophysical, and geochemical information imposes clear restrictions on the origin and evolution of the Earth-Moon system (e.g., Canup 2008, 2012; Ćuk and Stewart 2012; Young et al. 2016). In regard to geochemical constraints, one of the most puzzling conundrums is posed by the similar isotopic fingerprints of the Earth and the Moon (e.g., Wiechert et al. 2001; Armytage et al. 2012; Zhang et al. 2012; Young et al. 2016; Schiller et al. 2018), together with the apparent lunar depletion in volatile elements (e.g., Ringwood and Kesson 1977; Wanke et al. 1977; Albarède et al. 2015; Taylor 2014). This apparent lunar volatile depletion is most notable in the low K content in comparison to U, a finding based on chemical analyses of samples collected from the lunar surface and lunar meteorites, and on spectroscopic observations of the lunar near-surface, despite both having been heavily processed in the past ~ 4.4 billion years.</p><p>In the past 4.4 billion years, space has been a harsh environment for our Moon, especially in the beginning, when the young Sun was still very active and the young Moon was continuously bombarded by meteorites of varying sizes. Solar wind and micro-meteoritic interactions with the lunar surface led to rapid and intensive processing of the lunar crust. Hence, the K/U depletion trend observable on today's lunar surface does not necessarily reflect a K/U ratio valid for the Moon in its entirety. We model the evolution of the abundances of the major elements over the past 4.3 to 4.4 billion years to derive the composition of the original lunar crust. Accounting for this processing, our model results show that the original crust is much less depleted in volatiles than the surface observable today, exhibiting a K/U ratio compatible with Earth and the other terrestrial planets, which strengthens the theory of a terrestrial origin for the Moon.</p>

Evidence from the surface configuration of the Moon on its dynamical evolution

1967 ◽  
Vol 296 (1446) ◽  
pp. 298-303
Keyword(s):  
Lunar Surface ◽  
High Velocity ◽  
Dynamical Evolution ◽  
Great Majority ◽  
Major Axis ◽  
The Moon ◽  
Moon System ◽  
The Past ◽  
The Earth ◽  
High Velocity Impacts

Examination of the Moon through large telescopes reveals a multitude of fine detail down to a scale of 1 km or less. The most prominent feature of the lunar surface is the abundance of circular craters. Many investigators agree that a great majority of these craters have been caused by explosions associated with high velocity impacts. It is further generally assumed that the majority of these high velocity impacts took place during the earliest stages of development of the present Earth-Moon system. The morphology of the Moon surface appears in dynamical considerations in the following way. We know from the work of G. H. Darwin that the Moon has been steadily retreating from the Earth. Dynamical considerations suggest that the period of rotation of the Moon on the average equals its period of revolution about the Earth. Thus when the Moon approaches the Earth, its rotation would be accelerated. Since the Moon, like the Earth, approximates to a fluid body, we should expect that a figure of the Moon would have changed in response to its changing rate of rotation. If the craters formed at a time at which the Moon’s figure was markedly different from the present, then initially circular craters would be deformed and any initially circular depression would tend to change into an elliptically shaped depression, with the major axis of the ellipse along the local meridian. Study of the observed distortions of the craters can give evidence as to the past shape of the Moon, provided the craters formed at a time when the Moon possessed a different surface ellipticity. I should like to examine the limitations the present surface structure places on the past dynamical history of the Moon. I will first review briefly calculations bearing on the dynamical evolution of the Earth-Moon system and the implications these calculations have on the past shape of the lunar surface.

scholarly journals Effects of the Moon on the Earth in the Past, Present and Future

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Rina Rast ◽  
Sarah Finney ◽  
Lucas Cheng ◽  
Joland Schmidt ◽  
Kessa Gerein ◽  
...  
Keyword(s):  
Lunar Surface ◽  
Space Exploration ◽  
Modern Science ◽  
Rotational Axis ◽  
The Moon ◽  
Natural Satellite ◽  
Human Interest ◽  
The Past ◽  
The Earth ◽  
Stabilizing Effect

The Moon has fascinated human civilization for millennia. Exploration of the lunar surface played a pioneering role in space exploration, epitomizing the heights to which modern science could bring mankind. In the decades since then, human interest in the Moon has dwindled. Despite this fact, the Moon continues to affect the Earth in ways that seldom receive adequate recognition. This paper examines the ways in which our natural satellite is responsible for the tides, and also produces a stabilizing effect on Earth’s rotational axis. In addition, phenomena such as lunar phases, eclipses and lunar libration will be explained. While investigating the Moon’s effects on the Earth in the past and present, it is hoped that human interest in it will be revitalized as it continues to shape life on our blue planet.  

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

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.

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.

Origin and evolution of the lunar surface: the major questions remaining

1977 ◽  
Vol 285 (1327) ◽  
pp. 555-559 ◽  
Keyword(s):  
Lunar Surface ◽  
Transport Mechanism ◽  
Large Scale ◽  
Source Material ◽  
Lava Flows ◽  
The Moon ◽  
Surface Transport ◽  
Origin And Evolution ◽  
Major Factors ◽  
Scale Surface

The major factors in the evolution of the lunar surface have not been determined yet. Huge lava flows and lunar differentiation, though commonly assumed, is in discord with much of the evidence. The alternative is for most of the surface to represent the last stages of accretion of the Moon only, with the chemical differentiation having taken place previously in the source material. Radar, seismic, surface exposure, and mascon evidence can then be accounted for. A large-scale surface transport mechanism of soil must then have been present.

Lunar Environment

1993 ◽  
Vol 46 (6) ◽  
pp. 278-284 ◽  
Author(s):  
Lajpat R. Utreja
Keyword(s):  
Lunar Surface ◽  
Surface Characteristics ◽  
Major Elements ◽  
Human Beings ◽  
The Moon ◽  
Test Bed ◽  
Physical Constants ◽  
Geochemical Properties ◽  
Lunar Environment ◽  
Natural Test

As one of the key elements of the Space Exploration Initiative, the Moon provides a waypoint for scientific exploration and travel to Mars. The Moon’s stable ground in the vacuum of space is an ideal platform for astronomical observatories. Conditions on the Moon are similar to what human beings will face on other planets, so it is a natural test bed to prepare for a manned mission to Mars. A knowledge of the lunar environment is therefore important before undertaking any missions of construction, operations, and habitation on the lunar surface. The purpose of this paper is to review and assemble information on the lunar environment so that engineers and scientists can refer to this as they begin lunar-based engineering studies. The lunar environment is categorized into three major elements: lunar physical constants, lunar atmosphere, and lunar surface. The description of lunar size, orientation, period of rotation, and lunar month are all treated as part of lunar physical constants. Lunar atmosphere includes gas composition, pressure and density, solar flux and radiation, micrometeorite flux, and lunar dust. The geophysical and geochemical properties are provided as lunar surface characteristics. The geophysical properties include terrain characteristics, topography and surface tremors; soil and rock characteristics; mechanical, thermal, electrical, magnetic, and optical properties. The chemical composition of the regolith and rocks are described in geochemical properties.

scholarly journals ZONES OF RECENT ACTIVATION AND SCHEME OF THE EARTH CRUST PERMEABILITY OF UKRAINE

2021 ◽  
Vol 17 (1) ◽  
pp. 75-84
Author(s):  
V.V. Gordienko ◽  
L.Ya. Gordienko ◽  
J.A. Goncharova ◽  
V.M. Tarasov
Keyword(s):  
Surface Waters ◽  
Previous Analysis ◽  
Relevant Information ◽  
Earth’S Crust ◽  
Near Surface ◽  
The Past ◽  
The Earth ◽  
Continue Research ◽  
Earth's Crust ◽  
Background Gas

An attempt is considered to supplement the criteria for identifying zones of recent activation in the territory of Ukraine with another one — data on the results of studies of helium concentration in ground-water. The previous analysis of information showed that as regional criteria, information can be applied on anomalies in heat flow, increased electrical conductivity of Earth’s crustal and the upper mantle rocks, distribution of mantle gravitational anomalies, and surface uplifts over the past millions of years. They were chosen among others precisely because of the dissemination of relevant information throughout the country. This requirement is also met by the permeability Scheme of the earth’s crust of Ukraine, which is a fragment of the permeability Scheme of the earth’s crust of the European part of the USSR based on the results of helium studies. The principal applicability of such information for solving the problem is shown. Areas of maximum helium concentrations in near-surface waters are indicated, primarily those associated with disjunctive dislocation. Theу are concentrated in the south-west of Ukraine and in Moldova. The disadvantages of the Scheme are noted, due to poor study and significant variations in background gas concentrations, directly caused not by recent activation, but by the peculiarities of helium generation by rocks of the upper part of the earth’s crust. There are inconsistencies between the previously obtained ideas about the activated zones and the data of the Scheme. They are especially large in the Carpathian, Crimean and Donetsk regions, and are noticeable in others. Therefore, it seems necessary, first, to continue research, thicken the network of observations and develop a methodology for analyzing their results.

Earth's journey

2016 ◽  
Vol 12 (1) ◽  
pp. 4197-4203
Author(s):  
Leonard Van Zanten
Keyword(s):  
Orbital Period ◽  
The Sun ◽  
The Moon ◽  
The Earth ◽  
Single Period ◽  
Single Orbit ◽  
Full Turn ◽  
Fixed Axis ◽  
In The Beginning ◽  
Current Science

In the beginning the earth was flat and no one was to prove that it was round, but with the advent in science this is now quite obvious.  But no less obvious will be the fact that the earth has its seasons due to a rotation of precession rather than the fixed immovable position that current science has given it.  And that in a manner of speaking the earth, like unto the moon orbiting the earth, also appears to have a single period of rotation for each orbital period that it makes around the sun.The earth thus for each single orbit around the sun makes one full turn of precession which gives it its seasons.  That turn of precession then comes short of that one full turn of orbit by about 20 minutes.  And it is by those 20 minutes each year that the earth appears to have a precession lasting 26.000 years; the axis of the earth pointing to the star called Polaris and by one half thereof (13.000 years) graduating towards the star called Vega.It however is not a precession, but rather a "regression," even as the seasons do not come about by a fixed axis but rather by a precessional axis.   

scholarly journals Experimental Study of Torque Using a Small Scoop on the Lunar Surface

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Long Xue ◽  
Baichao Chen ◽  
Zhenjia Zhao ◽  
Zhaolong Dang ◽  
Meng Zou
Keyword(s):  
Experimental Study ◽  
Bulk Density ◽  
Lunar Surface ◽  
Great Influence ◽  
Test Results ◽  
The Moon ◽  
Rotating Speed ◽  
Simple Apparatus ◽  
The Earth

Chinese missions to the moon are planned to sample the regolith and return it to the earth. Microscale excavators may be good candidates for these missions, as they would significantly reduce the launch mass. Thus, it is necessary to research the interaction between the scoop and the regolith being sampled. We present the development of a simple apparatus to measure excavation torque. All tests were conducted using TYII-2 regolith simulant with gravels. The test results show that, under loose regolith conditions, the penetrating angle and the bulk density had a great influence on the excavation torque, while the rotating speed had little effect. However, when the bulk density was compact, the rotating speed did influence the excavation torque. The excavation torque increased sharply when the scoop encountered the gravels; actually, some of the parameters will influence the value of the torque such as the diameter, quantity, and position and inbuilt depth of the gravels. When the excavation torque sharply increases, the operation should be immediately stopped and checked.

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