Earth Keeping balance... Aug 25, 2006 14:36:06 GMT -6
Post by Chicago Astronomer Joe on Aug 25, 2006 14:36:06 GMT -6
Planet Earth may have 'tilted' to keep its balance
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."
Full story here: www.physorg.com/news75725492.html
Earth wobbles...but won't fall down.