Patterns in Earth's Magnetic Field Morph Every 1000 Years --"The Reason is a Mystery"
July 09, 2017
Some 800,000 years ago, a magnetic compass' needle would have pointed south because the Earth's magnetic field was reversed. These reversals typically happen every several hundred thousand years. The geomagnetic field is critical to life on Earth. Without it, charged particles from the sun (the "solar wind") would blow away the atmosphere, scientists say. The field also aids in human navigation and animal migrations in ways scientists are only beginning to understand. Centuries of human observation, as well as the geologic record, show our field changes dramatically in its strength and structure over time.
Scientists have identified patterns in the Earth's magnetic field that evolve on the order of 1,000 years, providing new insight into how the field works and adding a measure of predictability to changes in the field not previously known.
The discovery also will allow researchers to study the planet's past with finer resolution by using this geomagnetic "fingerprint" to compare sediment cores taken from the Atlantic and Pacific oceans. Results of the research, which was supported by the National Science Foundation, were recently published in Earth and Planetary Science Letters.
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