When a large body strikes a planet or moon, material is ejected, thereby creating a hole in the planet and a local deficit of mass.

当一个大型天体撞击行星或月球时，物质会被抛射出去，从而在行星上形成一个洞，造成局部质量不足的现象。

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In one simulation, a planet with the mass of Neptune situated in the habitable zone of a star - not too hot, not too cold - was given a moon the size of Earth.

在一种模拟的情景中，一个与天王星大小差不多的行星处在一个星球的可栖居的地带，不冷不热，并且周围有一个地球大小的恒星。

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As another example the center of mass of the earth and moon moves in an approximately circular orbit around the sun.

作为另一个例子，地球和月亮的质心就是在一个绕太阳的近似的圆轨道上运行。

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Research is being carried out by the Marine Conservation Society following mass strandings of moon jellyfish in north Wales.

BBC: Lion's mane jellyfish

Sun Myung Moon's Unification Church is best known through events like its mass weddings, where thousands of couples are married at the same time, having only just met their lifetime partner.

BBC: Obituary: Sun Myung Moon

La Masa Critical (Critical Mass) takes over the streets of the Argentine capital on the first Sunday of each month and every full moon, and the route is completely spontaneous each time.

BBC: Buenos Aires�� Critical Mass