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Credit & Copyright: Gary A. Glatzmaier
(UCSC)
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
magma rise outward, forced into a
helical motion by the
spin of the Earth.
This motion, many geologists now believe,
regenerates Earth's magnetism.
Pictured above, a computer simulation shows the resulting
magnetic field lines out to two Earth radii,
with blue lines directed inward and yellow lines directed outward.
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A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: magnetic field - Earth
Publications with words: magnetic field - Earth
See also: