TNRTB Archive – Retained for reference information
A team of Japanese geophysicists have performed the most realistic simulations of Earth’s interior dynamics to date, and their results confirm a general understanding of Earth’s formation and remove a notable young-earth objection to the dynamo model of geomagnetic fields. Using a powerful supercomputer, scientists were able to reproduce some key theoretical expectations in their models of the dynamo responsible for generating Earth’s magnetic field. Their analysis showed that the Ekman number (which represents the relative importance of viscosity to Earth’s rotation rate) must be fine-tuned. After reducing the Ekman number an order of magnitude lower than previous simulations, the dynamo was found to be in a predicted quasi-Taylor state where viscosity plays a negligible role in the core dynamics. These more realistic simulations showed polarity reversals matching those found in the geologic record. In addition, the simulated reversals showed precursors that mimic trends seen in geomagnetic data, suggesting a long overdue reversal may be starting on Earth. If true, humanity’s arrival on Earth was optimally timed to avoid the deleterious effects that occur during a reversal.
- Futoshi Takahashi, Masaki Matsushima, and Yoshimori Honkura, “Simulations of a Quasi-Taylor State Field Including Polarity Reversals on the Earth Simulator,” Science 309 (2005): 459-61.
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