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Past extent of lunar permanently shadowed areas

As the Moon migrated away from Earth, it experienced a major spin axis reorientation. Permanently shadowed regions (PSRs), which are thought to have trapped ices and are a main focus of lunar exploration, appeared and grew after this (Cassini state) transition and are often younger than their host c...

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Detalles Bibliográficos
Autores principales: Schörghofer, Norbert, Rufu, Raluca
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Association for the Advancement of Science 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499310/
https://www.ncbi.nlm.nih.gov/pubmed/37703378
http://dx.doi.org/10.1126/sciadv.adh4302
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author Schörghofer, Norbert
Rufu, Raluca
author_facet Schörghofer, Norbert
Rufu, Raluca
author_sort Schörghofer, Norbert
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description As the Moon migrated away from Earth, it experienced a major spin axis reorientation. Permanently shadowed regions (PSRs), which are thought to have trapped ices and are a main focus of lunar exploration, appeared and grew after this (Cassini state) transition and are often younger than their host craters. Here, we calculate the lunar spin axis orientation and the extent of PSRs based on recent advances for the time evolution of the Earth-Moon distance. The solar declination reached twice its current value 2.1 billion years (Ga) ago, when the PSR area was about half as large. The PSR area becomes negligible beyond 3.4 Ga ago. The site of an artificial impact in Cabeus Crater, where various volatiles have been detected, became continuously shadowed only about 0.9 Ga ago, and hence, cold-trapping has continued into this relatively recent time period. Overall estimates for the amount of cold-trapped ices have to be revised downward.
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spelling pubmed-104993102023-09-14 Past extent of lunar permanently shadowed areas Schörghofer, Norbert Rufu, Raluca Sci Adv Earth, Environmental, Ecological, and Space Sciences As the Moon migrated away from Earth, it experienced a major spin axis reorientation. Permanently shadowed regions (PSRs), which are thought to have trapped ices and are a main focus of lunar exploration, appeared and grew after this (Cassini state) transition and are often younger than their host craters. Here, we calculate the lunar spin axis orientation and the extent of PSRs based on recent advances for the time evolution of the Earth-Moon distance. The solar declination reached twice its current value 2.1 billion years (Ga) ago, when the PSR area was about half as large. The PSR area becomes negligible beyond 3.4 Ga ago. The site of an artificial impact in Cabeus Crater, where various volatiles have been detected, became continuously shadowed only about 0.9 Ga ago, and hence, cold-trapping has continued into this relatively recent time period. Overall estimates for the amount of cold-trapped ices have to be revised downward. American Association for the Advancement of Science 2023-09-13 /pmc/articles/PMC10499310/ /pubmed/37703378 http://dx.doi.org/10.1126/sciadv.adh4302 Text en Copyright © 2023 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). https://creativecommons.org/licenses/by-nc/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license (https://creativecommons.org/licenses/by-nc/4.0/) , which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.
spellingShingle Earth, Environmental, Ecological, and Space Sciences
Schörghofer, Norbert
Rufu, Raluca
Past extent of lunar permanently shadowed areas
title Past extent of lunar permanently shadowed areas
title_full Past extent of lunar permanently shadowed areas
title_fullStr Past extent of lunar permanently shadowed areas
title_full_unstemmed Past extent of lunar permanently shadowed areas
title_short Past extent of lunar permanently shadowed areas
title_sort past extent of lunar permanently shadowed areas
topic Earth, Environmental, Ecological, and Space Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499310/
https://www.ncbi.nlm.nih.gov/pubmed/37703378
http://dx.doi.org/10.1126/sciadv.adh4302
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