What is Giant-impact hypothesis?, Explain Giant-impact hypothesis, Define Giant-impact hypothesis

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926 بار بازدید - 6 سال پیش - #Giant-impacthypothesis
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~~~ Giant-impact hypothesis ~~~

Title: What is Giant-impact hypothesis?, Explain Giant-impact hypothesis, Define Giant-impact hypothesis
Created on: 2019-02-15
Source Link: https://en.wikipedia.org/wiki/Giant-i...

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Description: The giant-impact hypothesis, sometimes called the Big Splash, or the Theia Impact suggests that the Moon formed out of the debris left over from a collision between Earth and an astronomical body the size of Mars, approximately 4.5 billion years ago, in the Hadean eon; about 20 to 100 million years after the Solar System coalesced. The colliding body is sometimes called Theia, from the name of the mythical Greek Titan who was the mother of Selene, the goddess of the Moon. Analysis of lunar rocks, published in a 2016 report, suggests that the impact may have been a direct hit, causing a thorough mixing of both parent bodies.The giant impact hypothesis is currently the favored scientific hypothesis for the formation of the Moon. Supporting evidence includes:  Earth's spin and the Moon's orbit have similar orientations. Moon samples indicate that the Moon's surface was once molten. The Moon has a relatively small iron core. The Moon has a lower density than Earth. There is evidence in other star systems of similar collisions, resulting in debris disks. Giant collisions are consistent with the leading theories of the formation of the Solar System. The stable-isotope ratios of lunar and terrestrial rock are identical, implying a common origin.However, there remain several questions concerning the best current models of the giant-impact hypothesis. The energy of such a giant impact is predicted to have heated Earth to produce a global magma ocean, and evidence of the resultant planetary differentiation of the heavier material sinking into Earth's mantle has been documented. However, as of 2015 there is no self-consistent model that starts with the giant-impact event and follows the evolution of the debris into a single moon. Other remaining questions include when the Moon lost its share of volatile elements and why Venus—which experienced giant impacts during its formation—does not host a similar moon.

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6 سال پیش در تاریخ 1397/11/26 منتشر شده است.
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