Forming the Moon from terrestrial silicate-rich material

Meijer, R.J. de; Anisichkin, V. F.; Westrenen, W. van

doi:10.1016/j.chemgeo.2012.12.015

Cited by 22 publications

(21 citation statements)

References 74 publications

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“…In the final state the total energy of the Earth-Moon system (EM) is (according to De Meijer et al, 2013) given by:…”

Section: Methodsmentioning

confidence: 99%

“…As shown in De Meijer et al (2013) the energy of the two-body state, being the sum of its rotational and potential energy, has a maximum value at an Earth-Moon distance of r max . The Moon mass has to be placed beyond r max and the required energy, termed the release energy, is calculated from the corresponding changes in rotational and potential energy, as given in De Meijer et al (2013):…”

Section: Energetics Of Moon Formationmentioning

confidence: 99%

“…It should be pointed out that this lunar mass does not need to consist of a single body -in the calculations only its centre of mass is considered. The energy required for the Moon material to be placed into an orbit beyond the Roche limit is calculated by subtracting the rotational energy of the ground state from the energy of the system with a Moon at the Roche limit (De Meijer et al, 2013).…”

Section: General Approachmentioning

confidence: 99%

“…In the hypothesis of De Meijer et al (2013), a shock wave triggered by an explosion of a natural nuclear georeactor near the coremantle boundary (CMB) of the Earth ejected overlying silicate material into orbit (De Meijer & Van Westrenen, 2008). This explosion could have been triggered by a supercritical reactor caused by natural concentration and/or compaction due to the impact of a small asteroid (De Meijer et al, 2013). This model assumes no change in angular momentum with time and therefore does not require loss of momentum after the Moon-forming event (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Boundary conditions for the formation of the Moon

Reuver

Meijer²,

Kate

et al. 2015

Netherlands Journal of Geosciences

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Recent measurements of the chemical and isotopic composition of lunar samples indicate that the Moon's bulk composition shows great similarities with the composition of the silicate Earth. Moon formation models that attempt to explain these similarities make a wide variety of assumptions about the properties of the Earth prior to the formation of the Moon (the proto-Earth), and about the necessity and properties of an impactor colliding with the proto-Earth. This paper investigates the effects of the proto-Earth's mass, oblateness and internal core-mantle differentiation on its moment of inertia. The ratio of angular momentum and moment of inertia determines the stability of the proto-Earth and the binding energy, i.e. the energy needed to make the transition from an initial state in which the system is a rotating single body with a certain angular momentum to a final state with two bodies (Earth and Moon) with the same total angular momentum, redistributed between Earth and Moon. For the initial state two scenarios are being investigated: a homogeneous (undifferentiated) proto-Earth and a proto-Earth differentiated in a central metallic and an outer silicate shell; for both scenarios a range of oblateness values is investigated. Calculations indicate that a differentiated proto-Earth would become unstable at an angular momentum L that exceeds the total angular momentum of the present-day Earth-Moon system (L 0 ) by factors of 2.5-2.9, with the precise maximum dependent on the proto-Earth's oblateness. Further limitations are imposed by the Roche limit and the logical condition that the separated Earth-Moon system should be formed outside the proto-Earth. This further limits the L values of the Earth-Moon system to a maximum of about L/L 0 = 1.5, at a minimum oblateness (a/c ratio) of 1.2. These calculations provide boundary conditions for the main classes of Moon-forming models. Our results show that at the high values of L used in recent giant impact models (1.8 < L/L 0 < 3.1), the proposed proto-Earths are unstable before (Cuk & Stewart, 2012) or immediately after (Canup, 2012) the impact, even at a high oblateness (the most favourable condition for stability). We conclude that the recent attempts to improve the classic giant impact hypothesis by studying systems with very high values of L are not supported by the boundary condition calculations in this work. In contrast, this work indicates that the nuclear explosion model for Moon formation (De Meijer et al., 2013) fulfills the boundary conditions and requires approximately one order of magnitude less energy than originally estimated. Hence in our view the nuclear explosion model is presently the model that best explains the formation of the Moon from predominantly terrestrial silicate material.

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“…In the final state the total energy of the Earth-Moon system (EM) is (according to De Meijer et al, 2013) given by:…”

Section: Methodsmentioning

confidence: 99%

Section: Energetics Of Moon Formationmentioning

confidence: 99%

Section: General Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Boundary conditions for the formation of the Moon

Reuver

Meijer²,

Kate

et al. 2015

Netherlands Journal of Geosciences

Self Cite

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show abstract

“…We developed a hypothesis in which the Moon is formed of terrestrial material at an angular momentum close to the present value. Our hypothesis [7] is based on the concentration of fissile material concentrated in the Core-Mantle Boundary (CMB) of the Earth by a mineral called calcium silicate perovskite. By natural concentration the fissile material gets concentrated and spontaneously leads to georeactors [8].…”

mentioning

confidence: 99%