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Sep 26 14 9:12 PM
A geomagnetic reversal may happen sooner than expected Earth's magnetic field is shown in midreversal. COURTESY OF GARY A. GLATZMAIER University of California, Santa Cruz, AND PAUL H. ROBERTS University of California, Los Angeles More In This Article Reversals of the Earth's Magnetic Field Satellites Spy Changes to Earth's Magnetic Field Earth's Magnetic Field Flip Could Happen Sooner Than Expected Earth's magnetic north and south poles have flip-flopped many times in our planet's history—most recently, around 780,000 years ago. Geophysicists who study the magnetic field have long thought that the poles may be getting ready to switch again, and based on new data, it might happen earlier than anyone anticipated. The European Space Agency's satellite array dubbed “Swarm” revealed that Earth's magnetic field is weakening 10 times faster than previously thought, decreasing in strength about 5 percent a decade rather than 5 percent a century. A weakening magnetic field may indicate an impending reversal, which scientists predict could begin in less than 2,000 years. Magnetic north itself appears to be moving toward Siberia. Geophysicists do not yet fully understand the process of geomagnetic reversals, but they agree that our planet's field is like a dipole magnet. Earth's center consists of an inner core of solid iron and an outer core of liquid iron, a strong electrical conductor. The liquid iron in the outer core is buoyant, and as it heats near the inner core, it rises, cools off and then sinks. Earth's rotation twists this moving iron liquid and generates a self-perpetuating magnetic field with north and south poles.
Earth's magnetic field is shown in midreversal.
COURTESY OF GARY A. GLATZMAIER University of California, Santa Cruz, AND PAUL H. ROBERTS University of California, Los Angeles
Earth's magnetic north and south poles have flip-flopped many times in our planet's history—most recently, around 780,000 years ago. Geophysicists who study the magnetic field have long thought that the poles may be getting ready to switch again, and based on new data, it might happen earlier than anyone anticipated.
The European Space Agency's satellite array dubbed “Swarm” revealed that Earth's magnetic field is weakening 10 times faster than previously thought, decreasing in strength about 5 percent a decade rather than 5 percent a century. A weakening magnetic field may indicate an impending reversal, which scientists predict could begin in less than 2,000 years. Magnetic north itself appears to be moving toward Siberia.
Geophysicists do not yet fully understand the process of geomagnetic reversals, but they agree that our planet's field is like a dipole magnet. Earth's center consists of an inner core of solid iron and an outer core of liquid iron, a strong electrical conductor. The liquid iron in the outer core is buoyant, and as it heats near the inner core, it rises, cools off and then sinks. Earth's rotation twists this moving iron liquid and generates a self-perpetuating magnetic field with north and south poles.
Read more @ http://www.scientificamerican.com/article/earth-s-impending-magnetic-flip/
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