Moon News
MOON DAILY
Lunar Impact Flux Insights
illustration only
Lunar Impact Flux Insights
by Simon Mansfield
Sydney, Australia (SPX) Jul 08, 2024

Scholars have revisited the anchor points and historical construction of lunar crater chronology. Initially, the stratification of the Moon's near side relied on remote sensing data from ground-based telescopes and lunar orbiters before lunar samples were returned. As illustrated in Fig. 1, six manned missions and four robotic missions have brought back various samples, including basalts and volcanic glass, from different lunar geological units. These samples, through their lithology and thermal history, have been radiometrically dated to interpret the exposure ages of geological units. However, uncertainties persist due to unclear sample origins and challenges in identifying crater groups. The mixed nature of the regolith complicates the geological relationship between samples and specific units.

Impact craters are crucial for estimating the model ages of lunar geological units and other solid bodies in the solar system. Scholars often fit mathematical functions to establish lunar crater chronology functions, which predict model ages of geological units on the Moon and other solar system bodies. These predictions are confirmed by samples returned from space missions. For instance, samples from the Chang'e-5 mission have validated age determination techniques based on crater statistics, supporting the current lunar crater chronology model.

The article outlines the primary consensus and findings on lunar impact flux. The lunar impact record began during the solidification phase of the lunar magma ocean. Early impacts left no clear records due to the continuous differentiation of the magma ocean. Post solidification around 4.46 billion years ago, lunar impact structures started being preserved. The unexpectedly high content of highly siderophile elements (HSEs) in the lunar mantle suggests continuous bombardment by chondritic meteorites, possibly due to a late veneer impact event.

Comparing crater densities between lunar highlands and maria indicates a late heavy bombardment event, with the impact flux significantly higher around 3.8 billion years ago. The South Pole-Aitken (SPA) basin, possibly one of the largest lunar impact structures, may have formed around 4.3 billion years ago, followed by the late heavy bombardment (LHB) period around 3.8 billion years ago, leading to significant geological and biochemical evolution on the Moon and terrestrial planets. Since around 3.8 billion years ago, the lunar impact flux has remained relatively stable with occasional peaks but no significant overall changes, crucial for understanding the evolution of the Moon and terrestrial planets.

The article also addresses main disagreements and progress in resolving the controversy over the impact flux around 3.8 billion years ago. The primary uncertainty in lunar impact flux arises from mismatches between radiometric ages and model ages predicted by crater chronology. This uncertainty mainly stems from imperfect calibration of radiometric ages and crater production statistical data, common for geological units older than approximately 3.92 billion years, with diameters greater than 300 kilometers or less than about 10 meters. Additional issues include unclear isotopic ages of returned samples, uncertain origins of early lunar impact events and orbital dynamics, and the possibility of the late veneer forming after the solidification of the magma ocean.

Early lunar impact history constrains the final stages of planetary formation, potentially related to the orbital dynamics of the entire solar system. The relationship between the lunar late mantle and late heavy bombardment events is uncertain, complicating the attribution of early geophysical and geochemical characteristics to specific geological contexts. Fig. 5 shows crater groups in the lunar highlands resembling modern main-belt asteroid impactors, suggesting the main asteroid belt as the primary source for lunar impacts before 3.8 billion years ago. However, the source and dynamics of early impactors remain uncertain and require further research.

Finally, the authors summarize current research and future directions in the context of planned sample returns. Techniques such as sample analysis, high-resolution geological mapping, geophysical surveys, and orbital dynamics modeling can reduce uncertainties related to unclear sample origins and challenges in deriving crater groups but have not fundamentally addressed the weak understanding of early meteorite impact processes. Currently, calibrating lunar impact flux based on sample and crater structure remains elusive.

However, with upcoming lunar exploration missions set to return more samples and remote sensing data, future research will prioritize sampling sites older than 3.92 billion years. This approach aims to connect planetary evolution and orbital dynamics, resolve early impact history, and further enhance understanding of lunar impact flux. Designing new exploration missions and research strategies is expected to advance calibrating lunar impact flux and elucidating early meteorite impact processes.

Research Report:Impact Flux on the Moon

Related Links
Beijing Institute of Technology
Mars News and Information at MarsDaily.com
Lunar Dreams and more

Subscribe Free To Our Daily Newsletters
Tweet

RELATED CONTENT
The following news reports may link to other Space Media Network websites.
MOON DAILY
Eye Test for Lunar Impact Surveyor
Paris, France (SPX) Jul 08, 2024
The European Space Agency (ESA) has approved the Lunar Meteoroid Impact Observer (Lumio) mission, which will operate from an Earth-Moon Lagrange point to monitor meteoroid impacts on the lunar farside. Lumio will also conduct an advanced autonomous navigation experiment using its onboard camera to determine its orbit and distance from the Moon. The mission utilizes a sophisticated testbed named 'Retina' (Realistic Experimental FaciliTy for vision-based Navigation) to develop and verify the vision- ... read more

MOON DAILY
Voyagers of Mars: The First CHAPEA Crew's Yearlong Journey

Mars Likely Experienced Cold and Icy Conditions, Study Suggests

Europe's Earth Return Orbiter Advances to Next Development Stage

Martian Atmosphere Unveiled Through Innovative Use of Existing Technology

MOON DAILY
Titan's lakes may be shaped by waves

UH scientists discover massive energy imbalance on Saturn

Discovery of organic molecules on Saturn's moon

Enceladus Spills Its Guts through Strike-Slip Motion

MOON DAILY
NASA Evaluates Electrical Components for Europa Clipper Mission

Subaru Telescope Discovers New Objects Beyond the Kuiper Belt

NASA's Juno Observes Lava Lakes on Jupiter's Moon Io

Understanding Cyclones on Jupiter Through Oceanography

MOON DAILY
Leidos secures $476M NASA contract for ISS and Artemis Cargo Support

Real-life Spacesuit Innovation Recycles Urine into Drinking Water

MIT scientists develop way to toughen up 'good' bacteria, extend shelf life

Space Renaissance International Achieves Observer Status At U.N. COPUOS

MOON DAILY
MOON DAILY
Orion and SLS Gearing Up for Major Artemis Missions

SpaceX Falcon 9 rocket experiences rare failure

Virgin Galactic Unveils New Spaceship Manufacturing Facility in Arizona

Europe's new Ariane 6 rocket powers into space

MOON DAILY
Shenzhou XVII Crew Shares Post-Mission Insights with Media

Shenzhou XVIII Crew Successfully Completes Second Spacewalk

Chinese Scientists Develop Novel Rosa Roxburghii Varieties via Space Breeding

Shenzhou 18 Crew to Conduct Second Extravehicular Activities

MOON DAILY
Canadian space junk incident shows growing risks as SpaceX launches thousands of Starlinks

Quadrupolar Nuclei Measured Using Zero-Field NMR for the First Time

Researchers Uncover New Insights into High-Temperature Superconductivity in Copper Oxides

Serbia top court opens way for disputed lithium mining project

Subscribe Free To Our Daily Newsletters




The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.