No. 12: Fall 1980
NASA's Magnetic Field Satellite has confirmed a trend that goes as far back as Gauss in 1830; namely, that the terrestrial magnetic field is decreasing in strength. At the rate measured by the satellite, the Earth's field will hit zero in about 1200 years. Of course, NASA's scientists warn that the observed decrease may only be a temporary fluctuation. The geological record seems to register a long history of magnetic field reversals, with great biological changes coinciding with the field flips.
(Nonymous; "Magsat Down: Magnetic Field Declining," Science News, 117:407, 1980.)
Comment. Some field reversals have been within the time of man; 12,000 years ago and less. What happens to life forms dependent upon the earth's field for navigation during a reversal? Can they evolve new navigation methods in only a few thousand years?