The Earth's magnetic field is generated as the molten iron of the Earth's outer core revolves around its solid inner core; when surges in the molten iron occur, magnetic tempests are created.

地球磁场是由地球外核的熔铁围绕固体内核旋转而产生的；当铁水激增，就会发生磁暴。

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The Earth's magnetic field is generated by currents flowing in Earth's outer core.

地球磁场由地球外核中的电流产生。

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The innermost region of the Earth's outer core periodically flows faster or slower, and this action "tugs" at the planet's magnetic field, says Gillet.

地球外核最深区域呈阶段性快慢流动，这一行动“拽动”了地球磁场，吉莱说。

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The inner core, made of very pure, solid iron, rotates along with the outer core, dragging the Earth's magnetic field with them.

BBC: Earth's wobbles reveal deep secrets

The research could help test simulations of how the outer, fluid core generates the Earth's magnetic field, which shields our planet and the teeming life on it from harmful cosmic rays.

BBC: NEWS | Science/Nature | Earth's core runs ahead of crust