Editing Giant-impact hypothesis (section)

==Alternative hypotheses==
{{main|Origin of the Moon}}

Other mechanisms that have been suggested at various times for the Moon's origin are that the Moon was spun off from Earth's molten surface by [[centrifugal force]];<ref name="Binder 1974 53–76"/> that it was formed elsewhere and was subsequently [[lunar capture|captured]] by Earth's gravitational field;<ref name=icarus24_256/> or that Earth and the Moon formed at the same time and place from the same [[accretion disk]]. None of these hypotheses can account for the high [[angular momentum]] of the Earth–Moon system.<ref name=areps15/>

Another hypothesis attributes the formation of the Moon to the impact of a large asteroid with Earth much later than previously thought, creating the satellite primarily from debris from Earth. In this hypothesis, the formation of the Moon occurs 60–140 million years after the formation of the Solar System (as compared to hypothesized Theia impact at 4.527 ± 0.010 billion years).<ref name=taylor1998/> The asteroid impact in this scenario would have created a magma ocean on Earth and the proto-Moon with both bodies sharing a common plasma metal vapor atmosphere. The shared metal vapor bridge would have allowed material from Earth and the proto-Moon to exchange and equilibrate into a more common composition.<ref name=nature450_1206/><ref name=ngn20071219/>

Yet another hypothesis proposes that the Moon and Earth formed together, not from the collision of once-distant bodies. This model, published in 2012 by [[Robin Canup|Robin M. Canup]], suggests that the Moon and Earth formed from a massive collision of two planetary bodies, each larger than Mars, which then re-collided to form what is now called Earth.<ref>{{cite journal |title=Forming a Moon with an Earth-like Composition via a Giant Impact |first=Robin M. |last=Canup |journal=[[Science (journal)|Science]] |volume=338 |issue=6110 |pages=1052–1055 |date=2012-11-23 |doi=10.1126/science.1226073 |pmid=23076098 |pmc=6476314 |bibcode=2012Sci...338.1052C }}</ref><ref name=SimultaneousFormation/> After the re-collision, Earth was surrounded by a disk of material which accreted to form the Moon.<ref name=SimultaneousFormation/>

{{multiple image|total_width=800|align=center
|title=Moon – [[Oceanus Procellarum]] ("Ocean of Storms")|width1=614 |height1=228 |image1=14-236-LunarGrailMission-OceanusProcellarum-Rifts-Overall-20141001.jpg|caption1=Ancient [[rift valley]]s – rectangular structure (visible – topography – [[Gravity Recovery and Interior Laboratory|GRAIL gravity gradients]]) (October 1, 2014).|width2=1500 |height2=1500 |image2=PIA18822-LunarGrailMission-OceanusProcellarum-Rifts-Overall-20141001.jpg|caption2=Ancient [[rift valley]]s – context.|width3=1546 |height3=905 |image3=PIA18821-LunarGrailMission-OceanusProcellarum-Rifts-Closeup-20141001.jpg|caption3=Ancient [[rift valley]]s – closeup (artist's concept).}}