Tuesday, August 19, 2008

Changes In the Earth's Magnetic Field

The innermost part of the earth. The outer core extends from 2500 to 3500 miles below the earth's surface and is liquid metal. The inner core is the central 500 miles and is solid metal. Credit: John Lahr, USGS Open-File Report 99-132

Sloshing Inside Earth Changes Protective
Magnetic Field -- Live Science


Something beneath the surface is changing Earth's protective magnetic field, which may leave satellites and other space assets vulnerable to high-energy radiation.

The gradual weakening of the overall magnetic field can take hundreds and even thousands of years. But smaller, more rapid fluctuations within months may leave satellites unprotected and catch scientists off guard, new research finds.

A new model uses satellite data from the past nine years to show how sudden fluid motions within the Earth's core can alter the magnetic envelope around our planet. This represents the first time that researchers have been able to detect such rapid magnetic field changes taking place over just a few months.

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