Our Universe: the sciences & the human perspective

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Planet Earth May Have 'Tilted' To Keep Its Balance, Say Scientists

Source: Princeton University
Date: August 25, 2006


Imagine a shift in the Earth so profound that it could force our entire planet to spin on its side after a few million years, tilting it so far that Alaska would sit at the equator. Princeton scientists have now provided the first compelling evidence that this kind of major shift may have happened in our world's distant past.

By analyzing the magnetic composition of ancient sediments found in the remote Norwegian archipelago of Svalbard, Princeton University's Adam Maloof has lent credence to a 140-year-old theory regarding the way the Earth might restore its own balance if an unequal distribution of weight ever developed in its interior or on its surface.

The theory, known as true polar wander, postulates that if an object of sufficient weight -- such as a supersized volcano -- ever formed far from the equator, the force of the planet's rotation would gradually pull the heavy object away from the axis the Earth spins around. If the volcanoes, land and other masses that exist within the spinning Earth ever became sufficiently imbalanced, the planet would tilt and rotate itself until this extra weight was relocated to a point along the equator.

"The sediments we have recovered from Norway offer the first good evidence that a true polar wander event happened about 800 million years ago," said Maloof, an assistant professor of geosciences. "If we can find good corroborating evidence from other parts of the world as well, we will have a very good idea that our planet is capable of this sort of dramatic change."


This graphic shows the tilting of the Earth that might occur if a dramatic imbalance in the planet's mass distribution ever developed in the Arctic. According to the theory of true polar wander, a heavy spot in the Arctic -- caused by a very large upwelling of magma, for instance -- would reorient the planet over 5 to 20 million years so that the heavy spot would lie at the equator, changing the orientation of the Earth in relation to its poles. New evidence uncovered by the team of Princeton geoscientist Adam Maloof shows that this sort of reorientation may have occurred in the planet's distant past. (Graphic: Maloof Laboratory)Ads by Google Advertise on this site

...for rest of story: http://www.sciencedaily.com/releases/2006/08/060825132321.htm