Earth knocked off axis.
Kate (guest) 13 Mar 2011 09:51
I read that the Japan and Chile quakes knocked the Earth inches off its axis :( What will happen to us? :( I'm really scared!
Earth knocked off axis.
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» Earth knocked off axis.
Kate (guest) 13 Mar 2011 09:51
We've already talked about this elsewhere. Every severe earthquake reorients the planet's axis a little. This one apparently moved it about ten centimeters. You won't notice anything, and there's nothing to be scared of.
Hi Kate;
Other answers have already said that "nothing will happen", so I won't bother repeating that.
In this particular case, you have been misled by some sloppy language usage. For most people "knocked off of its axis" means a change in direction of the rotational axis. The earth currently has a 23.4 degree tilt of its axis when measured against the plane of its orbit around the sun. This won't change regardless of how many earthquakes we have.
What the various news stories are actually referring to is a very small change in the position of the axis, and not a change in its tilt.
Think of it like a toy gyroscope. If you take a spinning gyroscope, and try to tip the axis over, it will resist you, and translate some of that motion into precession. On the other hand, if you simply pick up the gyroscope (keeping the direction of the axis the same) and move it horizontally, it will not resist you, and no precession will occur.
What happened is more like the second scenario. A redistribution of mass on the surface of the earth has caused the exact calculated center of rotation to change ever so slightly. The earthquake ruptured along about 180 miles of length, with an average movement of several meters. That's a lot of rock mass, and when you change the distribution of mass on the surface of the sphere, it changes the 'balance', and causes the center of mass to move very slightly.
So that's what happened. Scientists estimated the new distribution of mass, and calculated how far the axis of the earth was displaced from its former position.
"Do you ever think about things you do think about?" - Henry Drummond to Matthew Harrison Brady in Inherit the Wind
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