Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon

Abstract First recognized by Laplace over two centuries ago, the Moon's present tidal‐rotational bulges are significantly larger than hydrostatic predictions. They are likely relics of a former hydrostatic state when the Moon was closer to the Earth and had larger bulges, and they were establis...

Full description

Saved in:
Bibliographic Details
Main Authors: Chuan Qin, Shijie Zhong, Roger Phillips
Format: Article
Language:English
Published: Wiley 2018-02-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2017GL076278
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850272662642753536
author Chuan Qin
Shijie Zhong
Roger Phillips
author_facet Chuan Qin
Shijie Zhong
Roger Phillips
author_sort Chuan Qin
collection DOAJ
description Abstract First recognized by Laplace over two centuries ago, the Moon's present tidal‐rotational bulges are significantly larger than hydrostatic predictions. They are likely relics of a former hydrostatic state when the Moon was closer to the Earth and had larger bulges, and they were established when stresses in a thickening lunar lithosphere could maintain the bulges against hydrostatic adjustment. We formulate the first dynamically self‐consistent model of this process and show that bulge formation is controlled by the relative timing of lithosphere thickening and lunar orbit recession. Viable solutions indicate that lunar bulge formation was a geologically slow process lasting several hundred million years, that the process was complete about 4 Ga when the Moon‐Earth distance was less than ~32 Earth radii, and that the Earth in Hadean was significantly less dissipative to lunar tides than during the last 4 Gyr, possibly implying a frozen hydrosphere due to the fainter young Sun.
format Article
id doaj-art-3e2fe601b5ef4b2db166846f3961ef29
institution OA Journals
issn 0094-8276
1944-8007
language English
publishDate 2018-02-01
publisher Wiley
record_format Article
series Geophysical Research Letters
spelling doaj-art-3e2fe601b5ef4b2db166846f3961ef292025-08-20T01:51:44ZengWileyGeophysical Research Letters0094-82761944-80072018-02-014531286129610.1002/2017GL076278Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and MoonChuan Qin0Shijie Zhong1Roger Phillips2Department of Physics University of Colorado Boulder Boulder CO USADepartment of Physics University of Colorado Boulder Boulder CO USADepartment of Earth and Planetary Sciences and McDonnell Center for the Space Sciences Washington University St. Louis MO USAAbstract First recognized by Laplace over two centuries ago, the Moon's present tidal‐rotational bulges are significantly larger than hydrostatic predictions. They are likely relics of a former hydrostatic state when the Moon was closer to the Earth and had larger bulges, and they were established when stresses in a thickening lunar lithosphere could maintain the bulges against hydrostatic adjustment. We formulate the first dynamically self‐consistent model of this process and show that bulge formation is controlled by the relative timing of lithosphere thickening and lunar orbit recession. Viable solutions indicate that lunar bulge formation was a geologically slow process lasting several hundred million years, that the process was complete about 4 Ga when the Moon‐Earth distance was less than ~32 Earth radii, and that the Earth in Hadean was significantly less dissipative to lunar tides than during the last 4 Gyr, possibly implying a frozen hydrosphere due to the fainter young Sun.https://doi.org/10.1002/2017GL076278Moon's shapegravity anomaliesEarth's tidal Qearly Earth
spellingShingle Chuan Qin
Shijie Zhong
Roger Phillips
Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon
Geophysical Research Letters
Moon's shape
gravity anomalies
Earth's tidal Q
early Earth
title Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon
title_full Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon
title_fullStr Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon
title_full_unstemmed Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon
title_short Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon
title_sort formation of the lunar fossil bulges and its implication for the early earth and moon
topic Moon's shape
gravity anomalies
Earth's tidal Q
early Earth
url https://doi.org/10.1002/2017GL076278
work_keys_str_mv AT chuanqin formationofthelunarfossilbulgesanditsimplicationfortheearlyearthandmoon
AT shijiezhong formationofthelunarfossilbulgesanditsimplicationfortheearlyearthandmoon
AT rogerphillips formationofthelunarfossilbulgesanditsimplicationfortheearlyearthandmoon