The planetary bodies of our solar system all tend to lie near this plane, since they were formed from the sun's spinning, flattened, proto-planetary disk.

太阳系内所有的行星成员的运行轨道都趋于这个平面，因为它们都是依据以太阳为轴心的平面轨道运行的。

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At their distances from the star, the rocky planetary core would have taken so long to form that the gaseous disk would have dissipated before the core could attract the gas.

就它们与恒星的距离而言，其石质行星核恐怕需要极其长的成型时间，以至于在星核能够俘获气体前周围的气态盘恐怕就已经消散殆尽了。

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When the planetary migration occurs under the tidally interaction of a planet and a disk of gas or a planetesimal, the orbital parameters, especially, semi-major axis, of this planet will be altered.

行星迁移发生在行星与气体或星子的星盘之间进行潮汐相互作用时，这造成行星轨道参数，特别是半主轴的变更。

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Proposed sources of such high heating in the early solar nebula have included everything from colliding asteroids, gamma ray bursts, solar x-ray flares, even lightning in the proto-planetary disk itself.

FORBES: Planets Made Easy: The Cosmic Glue That Binds Us All