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发帖数: 1285 | 1 Explanation: Why does the Earth have a magnetic field? The electrical
conductivity of the molten plasma of the Earth's core should be able to
damp the current magnetic field in only thousands of years. Yet our five
billion year old Earth clearly causes magnets to point to (defined) north.
The mystery is still being studied but recently thought related to motions
in the Earth's liquid outer core. Specifically, as portions of the outer
core cool and fall inward, oceans of the liquid iron-rich magm |
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