scholarly journals When the Moon had a magnetosphere

2020 ◽  
Vol 6 (42) ◽  
pp. eabc0865
Author(s):  
James Green ◽  
David Draper ◽  
Scott Boardsen ◽  
Chuanfei Dong
Keyword(s):  
Magnetic Intensity ◽  
The Moon ◽  
Field Modeling ◽  
Geocentric Distance ◽  
Lunar Samples ◽  
Magnetic Dipole Field ◽  
Maximum Protection ◽  
Solar Storms ◽  
Atmospheric Loss ◽  
Over Time

Apollo lunar samples reveal that the Moon generated its own global magnetosphere, lasting from ~4.25 to ~2.5 billion years (Ga) ago. At peak lunar magnetic intensity (4 Ga ago), the Moon was volcanically active, likely generating a very tenuous atmosphere, and, it is believed, was at a geocentric distance of ~18 Earth radii (RE). Solar storms strip a planet’s atmosphere over time, and only a strong magnetosphere would be able to provide maximum protection. We present simplified magnetic dipole field modeling confined within a paraboloidal-shaped magnetopause to show how the expected Earth-Moon coupled magnetospheres provide a substantial buffer from the expected intense solar wind, reducing Earth’s atmospheric loss to space.

scholarly journals Coordinated analysis of space weathering characteristics in lunar samples to understand water distribution on the Moon

2021 ◽  
Vol 27 (S1) ◽  
pp. 2260-2262
Author(s):  
Alexander Kling ◽  
Michelle Thompson ◽  
Jennika Greer ◽  
Philipp Heck
Keyword(s):  
Water Distribution ◽  
Space Weathering ◽  
The Moon ◽  
Lunar Samples

scholarly journals 6. The Nature of Asteroid Surfaces, from Optical Polarimetry

1977 ◽  
Vol 39 ◽  
pp. 243-251 ◽  
Author(s):  
A. Dollfus ◽  
J. E. Geake ◽  
J. C. Mandeville ◽  
B. Zellner
Keyword(s):  
The Body ◽  
Space Weathering ◽  
Carbonaceous Chondrites ◽  
The Moon ◽  
Laboratory Measurements ◽  
Surface Textures ◽  
Lunar Samples ◽  
Dark Material ◽  
Polarization Of Light ◽  
Scanning Electron

Telescopic observations of the polarization of light by asteroids are interpreted on the basis of a systematic polarimetric analysis of terrestrial, meteoritic and lunar samples. Laboratory measurements were made using samples with different surface textures, and scanning electron microscope pictures were used to investigate the influence of microtexture and crystalline structure.It is demonstrated that asteioid surfaces do not accumulate thick regolithic layers of micro-fragments, as do the Moon and Mercury. This is because the majority of debris ejected by impacts are lost, due to the low gravitational escape velocity from these bodies. However, asteroids are not bare rocks, but are coated with a thin layer of adhesive debris. This coating apparently has the composition of the body itself. The fact that there is no indication of significant maturation by space weathering suggests that the dust which coats the surface of asteroids is frequently replaced by further impacts.Asteroids may be classified polarimetrically in several groups: those in group C are made of very dark material and behave like carbonaceous chondrites, or very dark Fe-rich basalts; Those in group S correspond to silicates and stony meteorites. A third group represented by Asteroid 21 Lutetia and 16 Psyche may be metallic.

Disintegration of lunar samples over time: A test

2018 ◽  
Vol 53 (5) ◽  
pp. 1096-1103 ◽  
Author(s):  
L. A. Taylor ◽  
J. V. Hogancamp ◽  
L. A. Watts ◽  
S. J. Wentworth ◽  
P. D. Archer ◽  
...  
Keyword(s):  
Lunar Samples ◽  
Over Time

Drawing Down the Moon: Defining Magic in the Ancient Greco­Roman World

2019 ◽  
pp. 1-34
Author(s):  
Radcliffe G. Edmonds III
Keyword(s):  
Cultural Tradition ◽  
The Moon ◽  
Social Construct ◽  
Perceived Efficacy ◽  
Roman World ◽  
Greco Roman ◽  
The Social ◽  
Definition Of ◽  
Over Time

This introductory chapter provides a definition of magic. One of the most useful adjustments in the recent scholarship on magic has been the turn to considering magic as a dynamic social construct, instead of some particular reality. Magic is not a thing, but a way of talking. Thus, magic is a discourse pertaining to non-normative ritualized activity, in which the deviation from the norm is most often marked in terms of the perceived efficacy of the act, the familiarity of the performance within the cultural tradition, the ends for which the act is performed, or the social location of the performer. Such a discourse always has a history, since such a way of talking about things shifts over time as different people do the talking. When one speaks of “magic,” therefore, one should always explain: “magic for whom?” Any specific piece of evidence from the ancient Greco-Roman world provides an example of magic for that particular person, from one particular perspective. To speak of “magic in the ancient Greco-Roman world” is thus to refer to the whole range of things that various people in those cultures during those times could label as “magic.” The chapter then considers the act of drawing down the moon.

scholarly journals Scientific Knowledge of the Moon, 1609 to 1969

Geosciences ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
Charles Wood
Keyword(s):  
Scientific Knowledge ◽  
The Moon ◽  
Change Over Time ◽  
Critical Questions ◽  
Lunar Evolution ◽  
Lunar Craters ◽  
Over Time

Discoveries stemming from the Apollo 11 mission solved many problems that had vexed scientists for hundreds of years. Research and discoveries over the preceding 360 years identified many critical questions and led to a variety of answers: How did the Moon form, how old is its surface, what is the origin of lunar craters, does the Moon have an atmosphere, how did the Moon change over time, is the Moon geologically active today, and did life play any role in lunar evolution? In general, scientists could not convincingly answer most of these questions because they had too little data and too little understanding of astronomy and geology, and were forced to rely on reasoning and speculation, in some cases wasting hundreds of years of effort. Surprisingly, by 1969, most of the questions had been correctly answered, but a paucity of data made it uncertain which answers were correct.

scholarly journals PREFACE

1977 ◽  
Vol 285 (1327) ◽  
Keyword(s):  
Recent Decade ◽  
National Committee ◽  
Practical Reasons ◽  
Scientific Programme ◽  
Space Technology ◽  
The Moon ◽  
Related Space ◽  
Space Experiments ◽  
Lunar Samples ◽  
Academy Of Sciences

This volume presents papers delivered during the Royal Society discussion meeting held on 9-12 June 1975 under the auspices of the British National Committee on Space Research. The meeting was organized to present the findings of European and Commonwealth scientists who had participated in the analyses of lunar samples, both as principal and co-investigators in the Apollo lunar sample analysis programme and as analysts of the Luna samples provided by the U.S.S.R. Academy of Sciences under arrangements with national academies. Scientists from the U.S.A. and the U.S.S.R. were also invited to participate and so the meeting became sufficiently representative and its timing appropriate for the much needed attempt to review the whole of the work on lunar samples and the results of related space experiments. It was the purpose of the meeting, and of the Proceedings, to show how the new knowledge about the Moon, acquired over the recent decade from the intensive study made possible by the space technology developed in the U.S.A. and the U.S.S.R., had solved some and thrown light on other fundamental questions about the Moon. For practical reasons the meeting was overweighted in favour of British and European contributions; but this gave an opportunity for these laboratories to express their appreciation to N.A.S.A. and to the U.S.S.R Academy of Sciences for the opportunity to participate in a unique scientific programme. We hope that the publication will perform a service in bringing before scientists, and indeed the public in general, the remarkable increase in our understanding of the Moon which has resulted from the space programme and will show how international collaboration has been such an important feature of it.

scholarly journals The New Moon: Major Advances in Lunar Science Enabled by Compositional Remote Sensing from Recent Missions

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 498
Author(s):  
Deepak Dhingra
Keyword(s):  
Rapid Evolution ◽  
The Moon ◽  
New Paradigm ◽  
Lunar Science ◽  
Lunar Interior ◽  
New Findings ◽  
Lunar Samples ◽  
Resource Exploration ◽  
Globally Distributed

Volatile-bearing lunar surface and interior, giant magmatic-intrusion-laden near and far side, globally distributed layer of purest anorthosite (PAN) and discovery of Mg-Spinel anorthosite, a new rock type, represent just a sample of the brand new perspectives gained in lunar science in the last decade. An armada of missions sent by multiple nations and sophisticated analyses of the precious lunar samples have led to rapid evolution in the understanding of the Moon, leading to major new findings, including evidence for water in the lunar interior. Fundamental insights have been obtained about impact cratering, the crystallization of the lunar magma ocean and conditions during the origin of the Moon. The implications of this understanding go beyond the Moon and are therefore of key importance in solar system science. These new views of the Moon have challenged the previous understanding in multiple ways and are setting a new paradigm for lunar exploration in the coming decade both for science and resource exploration. Missions from India, China, Japan, South Korea, Russia and several private ventures promise continued exploration of the Moon in the coming years, which will further enrich the understanding of our closest neighbor. The Moon remains a key scientific destination, an active testbed for in-situ resource utilization (ISRU) activities, an outpost to study the universe and a future spaceport for supporting planetary missions.

On-orbit radiometric calibration over time and between spacecraft using the Moon

2003 ◽  
Author(s):  
Hugh H. Kieffer ◽  
Thomas C. Stone ◽  
Robert A. Barnes ◽  
Steven C. Bender ◽  
Robert E. Eplee, Jr. ◽  
...  
Keyword(s):  
Radiometric Calibration ◽  
The Moon ◽  
Over Time

Structure in the upper lunar crust

1977 ◽  
Vol 285 (1327) ◽  
pp. 469-473 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Elastic Moduli ◽  
Velocity Profiles ◽  
Depth Range ◽  
The Moon ◽  
Rock Layer ◽  
Lunar Crust ◽  
Seismic Profiles ◽  
Lunar Samples

Estimates are made of the degree of lithification and of structure densities which are compatible with lunar in situ seismic profiles in the top 30 km of the Moon. Estimates are based on comparison of results of passive and active lunar seismic experiments with the pressure dependence of elastic moduli for various classes of lunar samples. Competent rock, such as igneous rock or recrystallized breccias with crack porosity of not more than about 0.5 % are required to satisfy velocity profiles in the depth range 1-30 km. Velocity profiles in the upper 1 km are best satisfied by comminuted material to highly fractured lithic units. These estimates constrain those thermal and shock histories which are compatible with lunar seismic results. After crystallization, or recrystallization, rock below 1 km cannot have been exposed to more than moderate shock levels. In the uppermost 1 km, an unannealed and broken rock layer would imply low thermal conductivity resulting in possible temperatures at 1 km depth of several hundred kelvins.

Implantation of ions escaping the atmosphere of Mars within the regolith of Phobos, and Phobos’ surface ion weathering

2020 ◽  
Author(s):  
Quentin Nénon ◽  
Andrew R Poppe ◽  
Ali Rahmati ◽  
James P McFadden
Keyword(s):  
Solar Wind ◽  
Atomic Oxygen ◽  
The Moon ◽  
Ion Composition ◽  
Atmospheric Escape ◽  
The Past ◽  
Lunar Samples ◽  
Singly Charged

<p>Mars has lost and is losing its atmosphere into space. Strong evidences of this come from the observation of planetary singly charged heavy ions (atomic oxygen, molecular oxygen, carbon dioxide ions) by Mars Express and MAVEN. Phobos, the closest moon of Mars, orbits only 6,000 kilometers above the red planet’s surface and is therefore a unique vantage point of the planetary atmospheric escape, with the escaping ions being implanted within the regolith of Phobos and altering the properties of the moon’s surface.</p> <p>In this presentation, we aggregate all ion observations gathered in-situ close to the orbit of Phobos by three ion instruments onboard MAVEN, from 2015 to 2019, to constrain the long-term averaged ion environment seen by the Martian moon at all longitudes along its orbit. In particular, the SupraThermal and Thermal Ion Composition (STATIC) instrument onboard MAVEN distinguishes between solar wind and planetary ions. The newly constrained long-term ion environment seen by Phobos is combined with numerical simulations of ion transport and effects in matter.</p> <p>This way, we find that planetary ions are implanted on the near side of Phobos (pointing towards Mars) inside the uppermost tens of nanometers of regolith grains. The composition of near-side grains that may be sampled by future Phobos sample return missions is therefore not only contaminated by planetary ions, as seen in lunar samples with the terrestrial atmosphere, but may show a unique record of the past atmosphere of Mars.</p> <p>The long-term fluxes of planetary ions precipitating onto Phobos are so intense that these ions weather the moon’s surface as much as or more than solar wind ions. In particular, Martian ions accelerate the long-term sputtering and amorphization of the near side regolith by a factor of 2. Another implication is that ion weathering is highly asymmetric between the near side and far side of Phobos.</p>

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