| 翻訳と辞書 |
| Theia (planet) ： ウィキペディア英語版 |
Theia (planet)
Theia is a hypothesized ancient planetary-mass object in the early Solar System that according to the giant impact hypothesis collided with the Early Earth around 4.533 billion years ago (BYa).〔 According to the hypothesis, Theia was an Earth trojan about the size of Mars; if the impact were not glancing, it could have destroyed Earth. Models of the impact propose that Theia's debris gathered together around Earth to form what was the early Moon. After the debris from the collision flew into space, some scientists think that it originally formed two moons〔〔"Faceoff! The Moon's oddly different sides", ''Astronomy'', August 2014, 44-49.〕 which later merged to form the single Moon we know today. However, the two-moon hypothesis is not necessary to explain the difference in the faces of the near and far sides of the Moon. The theory also explains the reason that Earth's core is larger than it would be for a body its size, since according to the theory, Theia's core merged with Earth's.〔(A New Model for the Origin of the Moon )〕
==Orbit==
Theia was thought to have orbited in the L4 or L5 spots in the Earth's orbit. It grew to a Mars-like size and, through gravitational perturbation from Venus, was moved around and eventually set on a collision course with Earth.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Theia (planet)」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|