Collisionless encounters and the origin of the lunar inclination

  title={Collisionless encounters and the origin of the lunar inclination},
  author={Kaveh Pahlevan and Alessandro Morbidelli},
The Moon is generally thought to have formed from the debris ejected by the impact of a planet-sized object with the proto-Earth towards the end of planetary accretion. Models of the impact process predict that the lunar material was disaggregated into a circumplanetary disk and that lunar accretion subsequently placed the Moon in a near-equatorial orbit. Forward integration of the lunar orbit from this initial state predicts a modern inclination at least an order of magnitude smaller than the… Expand

Figures and Topics from this paper

Tidal evolution of the Moon from a high-obliquity, high-angular-momentum Earth
It is shown that tidal dissipation due to lunar obliquity was an important effect during the Moon’s tidal evolution, and the lunar inclination in the past must have been very large, defying theoretical explanations. Expand
A multiple-impact origin for the Moon
The hypothesis of lunar origin by a single giant impact can explain some aspects of the Earth–Moon system. However, it is difficult to reconcile giant-impact models with the compositional similarityExpand
Late veneer and late accretion to the terrestrial planets
Abstract It is generally accepted that silicate-metal (‘rocky’) planet formation relies on coagulation from a mixture of sub-Mars sized planetary embryos and (smaller) planetesimals that dynamicallyExpand
Tidal Evolution of the Earth–Moon System with a High Initial Obliquity
A giant-impact origin for the Moon is generally accepted, but many aspects of lunar formation remain poorly understood and debated. Ćuk et al. proposed that an impact that left the Earth–Moon systemExpand
Moonfalls: collisions between the Earth and its past moons
During the last stages of the terrestrial planet formation, planets grow mainly through giant-impacts with large planetary embryos. The Earth's Moon was suggested to form through one of theseExpand
Tidal dissipation in the lunar magma ocean and its effect on the early evolution of the Earth–Moon system
Abstract The present-day inclination of the Moon reflects the entire history of its thermal and orbital evolution. The Moon likely possessed a global magma ocean following the Moon-forming impact. InExpand
Early Dynamics of the Lunar Core
The Moon is known to have a small liquid core, and it is thought that in the distant past the core may have produced strong magnetic fields recorded in lunar samples. Here we implement a numericalExpand
Vertical angular momentum constraint on lunar formation and orbital history
  • Z. Tian, J. Wisdom
  • Physics, Medicine
  • Proceedings of the National Academy of Sciences
  • 2020
It is demonstrated that the recently proposed high-obliquity scenario is not consistent with the present Earth–Moon system and will have to be taken into account in all future investigations of the formation and evolution of the Moon. Expand
The origin of the Moon within a terrestrial synestia
The giant impact hypothesis remains the leading theory for lunar origin. However, current models struggle to explain the Moon's composition and isotopic similarity with Earth. Here we present a newExpand
Asteroid bombardment and the core of Theia as possible sources for the Earth's late veneer component
The silicate Earth contains Pt-group elements in roughly chondritic relative ratios, but with absolute concentrations <1% chondrite. This veneer implies addition of chondrite-like material withExpand


Origin of the Moon's orbital inclination from resonant disk interactions
It is shown that the Moon's substantial orbital inclination is probably a natural result of its formation from an impact-generated disk, and involves a gravitational resonance between the Moon and accretion-disk material, which can increase orbital inclinations up to ∼15°. Expand
Origin of the Moon in a giant impact near the end of the Earth's formation
This work reports a class of impacts that yield an iron-poor Moon, as well as the current masses and angular momentum of the Earth–Moon system, and suggests that the Moon formed near the very end of Earth's accumulation. Expand
The lunar orbit revisited, III
In this paper we present an investigation on the tidal evolution of a system of three bodies: the Earth, the Moon and the Sun. Equations are derived including dissipation in the planet caused by theExpand
We use a hybrid numerical approach to simulate the formation of the Moon from an impact-generated disk, consisting of a fluid model for the disk inside the Roche limit and an N-body code to describeExpand
A low mass for Mars from Jupiter’s early gas-driven migration
Simulation of the early Solar System shows how the inward migration of Jupiter to 1.5 au, and its subsequent outward migration, lead to a planetesimal disk truncated at 1’au; the terrestrial planets then form from this disk over the next 30–50 million years, with an Earth/Mars mass ratio consistent with observations. Expand
Satellite-Sized Planetesimals and Lunar Origin
Abstract Exploratory calculations using accretionary theory are made to demonstrate plausible sizes of second-largest, third-largest, etc., bodies at the close of planet formation in heliocentricExpand
Dynamics of Lunar Formation
▪ Abstract The giant impact theory is the leading hypothesis for the origin of the Moon. This review focuses on dynamical aspects of an impact-induced lunar formation, in particular those areas thatExpand
Lunar-forming impacts: processes and alternatives
  • R. Canup
  • Physics, Medicine
  • Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2014
The formation of a protolunar disc by a giant impact with the early Earth is discussed, focusing on two classes of impacts: canonical impacts and high-angular-momentum impacts, both of which require subsequent processes for consistency with the current Earth and Moon. Expand
Tidal Dissipation in the Early Lunar Magma Ocean and its Role in the Evolution of the Earth-Moon System
Dissipation in the Earth drove the Moon outwards over time. As it did so, the Moon’s obliquity increased, reaching a maximum at the socalled Cassini state transition at a distance of ~30 Earth radiiExpand
The Tethered Moon
Abstract We address the thermal history of the Earth after the Moon-forming impact, taking tidal heating and thermal blanketing by the atmosphere into account. The atmosphere sets an upper bound ofExpand