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木星真的让地球的居住吗?

一项新研究Batygyin和劳克林表明,木星迁移期间向太阳系的内部区域系统形成的早期阶段扫清了宜居区域(适居带)从早期行星围绕太阳太大,与大气层太密集,支持生命。正如他们所说:

木星向内迁移从> 5个天文单位(AU)≈1.5 AU之前扭转方向,可以解释太阳系的总体质量较低的类地行星。

他们建议这个场景解释太阳系之间的差异和其他行星系统的大型行星在邻近的开始。

中我有很多问题:它怎么可能这样一个迁移的发生?有办法验证迁移假说与观测?会有怎样的不同的假想行星在该地区目前占领地球吗?如果这种迁移朝向太阳开始,阻止木星与太阳持续的向内和崩溃?是否有可能再这样一个迁移的发生吗?

回答

>木星真的让地球的居住吗?也许,但是很难讲。——我写了(答案)(https://physics.stackexchange.com/questions/160912/the-solar-system-explosion-in-the-nice-model/173692 # 173692)对物理问题得到一些更具体的问题;忍受我是否重用一点。>它怎么可能这样一个迁移的发生?(行星迁移)(http://en.wikipedia.org/wiki/Planetary_migration)所描述的太阳系(模型)(http://en.wikipedia.org/wiki/Nice_model)(或者,事实上,第二漂亮的模型,它的继任者)。基本上,气态巨行星开始在不同的轨道较轴比在今天。秩序,有一个变化:海王星更比天王星(生产订单木星、土星、海王星、天王星)。也有(五巨头)(http://en.wikipedia.org/wiki/Hypothetical_fifth_giant_planet)(实际上一个冰巨人),随后被驱逐。这将是类似于成分和天王星和海王星的大小。 Here's a quick summary of the Nice Model: 1. Planetesimals and Kuiper Belt Objects interact with the giants, moving Jupiter inwards a tad and the other three (or four) outwards. 2. Eventually, [resonances](http://en.wikipedia.org/wiki/Orbital_resonance) come into play. These are ratios between orbital periods. Jupiter and Saturn cross a mutual threshold. 3. Saturn moves outward and Jupiter moves inward. A chain of events happens, where Neptune and Uranus are dramatically moved outwards, with Neptune being chucked to the rear (and the hypothetical 5th giant being ejected). You can watch the video given in that question [here](http://www.youtube.com/watch?v=VXeOh3xmrQM). Here are the before and after pictures, <strike>stolen</strike> borrowed from that question: ![enter image description here][1] ![enter image description here][2] [1]: http://i.stack.imgur.com/YH88n.png [2]: http://i.stack.imgur.com/6SNpw.png I can, specifically, recommend the papers I mentioned there: [Fassett & Minton (2013)](http://www.nature.com/ngeo/journal/v6/n7/full/ngeo1841.html), [Deienno & Nesvorny (2014)](http://arxiv.org/pdf/1405.1880.pdf), [Brasser et al. (2009)](http://www.aanda.org/articles/aa/abs/2009/44/aa12878-09/aa12878-09.html), [Nesvorny (2011)](http://arxiv.org/pdf/1109.2949v1.pdf), [Nesvorny & Morbidelli (2012)](http://arxiv.org/pdf/1208.2957v1.pdf), and [Gomes, Levison, Tsiganis and Morbidelli (2005)](http://www.nature.com/nature/journal/v435/n7041/abs/nature03539.html) - in no particular order, I think. > Is there a way to verify the migration hypothesis with observations? Well, simulations were used in some of the mentioned papers, especially in those co-authored by Nesvorny, who was involved in recent developments of the Nice Model. These lead to the hypothetical 5th giant, because in some cases, it is necessary as a sort of sacrificial lamb, to prevent Uranus or Neptune from being flung out. We really can't observe this happening in real time, so simulations are our best shot. > How different would have been the hypothetical planets in the area currently occupied by Earth? The [Late Heavy Bombardment](http://en.wikipedia.org/wiki/Late_Heavy_Bombardment) might not have happened. That's a whole avenue of investigation into alternative astronomical history. It would involve fewer craters and possibly less fewer small collisions between some objects. It would be a calmer place. No migration = no LHB. Beyond that, it's hard for anyone to say. Detailed simulations are really difficult, because the *exact* conditions that matter - not just orbital positions - are hard to model. > If such a migration toward the Sun started, what prevented Jupiter from continuing inward and collapsing with the Sun? There just wasn't enough impetus from the encounter with Saturn to fling it inwards. A migration isn't just a planet rushing willy-nilly into space; it's a delicate system of slight orbital changes. All odds were against something like this happening. > Is it possible for such a migration to occur again? Only if the right resonances appear, which is unlikely.

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