Monday, March 1, 2010

The earth moves and its axis shifts

NASA scientists are now saying that the massive earthquake that hit Chile last Saturday (Corrected from "Thursday." What was I thinking?) was enough to actually shift Earth's axis by as much as three inches.

I won't even pretend to really understand how this works. It has to do with the movement of rocks in the planet's core and the actual shifting of Earth's weight from one area to another. Sort of like, over time, a person's weight may shift to the center of his/her body, causing a personal axis shift. That's about as close to an explanation of the phenomenon as I can get.

It turns out this is not an unusual occurrence. Whenever an earthquake of this magnitude occurs, it is likely to cause some wobbles in Earth's rotation and changes in the axis. JPL research scientist Richard Gross computed the changes that this particular earthquake caused. He estimates that it has shortened Earth's days by about 1.26 microseconds. A microsecond is one millionth of a second, so perhaps we can be forgiven if we don't notice the change.

The most dramatic effects of the earthquake and the ones that we notice, of course, are the effects that take place on the surface of Earth, the physical damage and the cost in human and animal life and suffering. But it is fascinating to note that the long-lasting results of such events are the ones that are hidden from our view, somewhere in the interior of our blue planet.

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