scholarly journals Lunar samples record an impact 4.2 billion years ago that may have formed the Serenitatis Basin

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Ana Černok ◽  
Lee F. White ◽  
Mahesh Anand ◽  
Kimberly T. Tait ◽  
James R. Darling ◽  
...  
Keyword(s):  
Atom Probe ◽  
Distribution Functions ◽  
Radiometric Dating ◽  
The Moon ◽  
Impact Cratering ◽  
Size Frequency Distribution ◽  
Lunar Samples ◽  
Lunar Impact ◽  
Absolute Age ◽  
Impact Simulations

AbstractImpact cratering on the Moon and the derived size-frequency distribution functions of lunar impact craters are used to determine the ages of unsampled planetary surfaces across the Solar System. Radiometric dating of lunar samples provides an absolute age baseline, however, crater-chronology functions for the Moon remain poorly constrained for ages beyond 3.9 billion years. Here we present U–Pb geochronology of phosphate minerals within shocked lunar norites of a boulder from the Apollo 17 Station 8. These minerals record an older impact event around 4.2 billion years ago, and a younger disturbance at around 0.5 billion years ago. Based on nanoscale observations using atom probe tomography, lunar cratering records, and impact simulations, we ascribe the older event to the formation of the large Serenitatis Basin and the younger possibly to that of the Dawes crater. This suggests the Serenitatis Basin formed unrelated to or in the early stages of a protracted Late Heavy Bombardment.

scholarly journals Large impact cratering during lunar magma ocean solidification

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
K. Miljković ◽  
M. A. Wieczorek ◽  
M. Laneuville ◽  
A. Nemchin ◽  
P. A. Bland ◽  
...  
Keyword(s):  
The Moon ◽  
Magma Ocean ◽  
Impact Cratering ◽  
Low Viscosity ◽  
Impact Flux ◽  
Lunar Samples ◽  
History Of ◽  
Lunar Evolution ◽  
Asteroid Dynamics ◽  
Lunar Basins

AbstractThe lunar cratering record is used to constrain the bombardment history of both the Earth and the Moon. However, it is suggested from different perspectives, including impact crater dating, asteroid dynamics, lunar samples, impact basin-forming simulations, and lunar evolution modelling, that the Moon could be missing evidence of its earliest cratering record. Here we report that impact basins formed during the lunar magma ocean solidification should have produced different crater morphologies in comparison to later epochs. A low viscosity layer, mimicking a melt layer, between the crust and mantle could cause the entire impact basin size range to be susceptible to immediate and extreme crustal relaxation forming almost unidentifiable topographic and crustal thickness signatures. Lunar basins formed while the lunar magma ocean was still solidifying may escape detection, which is agreeing with studies that suggest a higher impact flux than previously thought in the earliest epoch of Earth-Moon evolution.

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.

Transitional impact craters on the Moon: Insight into the effect of target lithology on the impact cratering process

2018 ◽  
Author(s):  
Gordon R. Osinski ◽  
Elizabeth A. Silber ◽  
Jacqueline Clayton ◽  
Richard A. F. Grieve ◽  
Kayle Hansen ◽  
...  
Keyword(s):  
Impact Craters ◽  
The Moon ◽  
Impact Cratering ◽  
The Impact ◽  
Insight Into

scholarly journals Oblique impact cratering experiments in brittle targets: Implications for elliptical craters on the Moon

2017 ◽  
Vol 135 ◽  
pp. 27-36 ◽  
Author(s):  
Tatsuhiro Michikami ◽  
Axel Hagermann ◽  
Tomokatsu Morota ◽  
Junichi Haruyama ◽  
Sunao Hasegawa
Keyword(s):  
Oblique Impact ◽  
The Moon ◽  
Impact Cratering

scholarly journals Dynamical Age Determination of Open Clusters

1980 ◽  
Vol 85 ◽  
pp. 221-222
Author(s):  
M. Buchholz ◽  
Th. Schmidt-Kaler
Keyword(s):  
Age Determination ◽  
Dynamical Theory ◽  
Distribution Functions ◽  
Open Clusters ◽  
Kolmogorov Smirnov ◽  
The Difference ◽  
Absolute Age ◽  
Image Position ◽  
Smirnov Test

The radial mass distribution (obtained by counting stars in strips) of the real cluster is compared successively to the distribution functions of a simulated cluster of 100 stars, each of which corresponds to a certain dynamical age, Tdyn, The value of Tdyn, belonging to the function most similar to the observed one is taken to be the dynamical age of the cluster. The radius is given in units of R1/2 (sphere containing half of the total mass); this unit is nearly time-independent. The difference between the distribution functions is measured by the maximum Δmax of the Kolmogorov-Smirnov test which is free from assumptions on the form of the distributions. The minimum in the plot Δmax vs Tdyn, indicates the age of the cluster. It is then converted into an absolute age, Tabs (in years), by The error due to the dynamical theory (limited number of distribution functions, etc.) is estimated at 12%, the error due to the uncertainty of diameter and mass of the cluster is about 30%. Unreliable results were obtained in case of strongly inhomogeneous reddening of the cluster. As an example, the plot of the test values for NGC 457 is given in Figure 1.

scholarly journals Was the moon magnetized by impact plasmas?

2020 ◽  
Vol 6 (40) ◽  
pp. eabb1475
Author(s):  
Rona Oran ◽  
Benjamin P. Weiss ◽  
Yuri Shprits ◽  
Katarina Miljković ◽  
Gábor Tóth
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Magnetic Anomalies ◽  
The Moon ◽  
Crustal Field ◽  
Impact Simulations ◽  
Magnetizing Field

The crusts of the Moon, Mercury, and many meteorite parent bodies are magnetized. Although the magnetizing field is commonly attributed to that of an ancient core dynamo, a longstanding hypothesized alternative is amplification of the interplanetary magnetic field and induced crustal field by plasmas generated by meteoroid impacts. Here, we use magnetohydrodynamic and impact simulations and analytic relationships to demonstrate that although impact plasmas can transiently enhance the field inside the Moon, the resulting fields are at least three orders of magnitude too weak to explain lunar crustal magnetic anomalies. This leaves a core dynamo as the only plausible source of most magnetization on the Moon.

scholarly journals Accretion of the Moon from non-canonical discs

2014 ◽  
Vol 372 (2024) ◽  
pp. 20130256 ◽  
Author(s):  
J. Salmon ◽  
R. M Canup
Keyword(s):  
Angular Momentum ◽  
Rotation Period ◽  
Major Axis ◽  
The Moon ◽  
Large Excess ◽  
Semi Major Axis ◽  
Earth’S Mantle ◽  
The Earth ◽  
Post Impact ◽  
Impact Simulations

Impacts that leave the Earth–Moon system with a large excess in angular momentum have recently been advocated as a means of generating a protolunar disc with a composition that is nearly identical to that of the Earth's mantle. We here investigate the accretion of the Moon from discs generated by such ‘non-canonical’ impacts, which are typically more compact than discs produced by canonical impacts and have a higher fraction of their mass initially located inside the Roche limit. Our model predicts a similar overall accretional history for both canonical and non-canonical discs, with the Moon forming in three consecutive steps over hundreds of years. However, we find that, to yield a lunar-mass Moon, the more compact non-canonical discs must initially be more massive than implied by prior estimates, and only a few of the discs produced by impact simulations to date appear to meet this condition. Non-canonical impacts require that capture of the Moon into the evection resonance with the Sun reduced the Earth–Moon angular momentum by a factor of 2 or more. We find that the Moon's semi-major axis at the end of its accretion is approximately 7 R ⊕ , which is comparable to the location of the evection resonance for a post-impact Earth with a 2.5 h rotation period in the absence of a disc. Thus, the dynamics of the Moon's assembly may directly affect its ability to be captured into the resonance.

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.

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