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Japan Earthquake May Have Shifted Earth's Axis
Zothecula writes "Using a complex model to perform a theoretical calculation based on a US Geological Survey, Richard Gross of NASA's Jet Propulsion Laboratory has determined that by changing the distribution of the Earth's mass, the earthquake that devastated Japan last Friday should have sped up the Earth's rotation, resulting in a day that is about 1.8 microseconds (1.8 millionths of a second) shorter."
... the work day got about 0.6 microseconds shorter, woo! Oh, wait....
Did I read that correctly? Did the summary explain to us what a microsecond is?
Shift happens.
Everytime I heard that the Earth's axis had been changed during the Chile earthquake, I figured it was the rotation axis. I thought it was a little far-fetched, but I wasn't one to argue with the data. However, it is NOT the rotational axis that was shifted and this article finally clarifies that. I read many others before (probably regurgitations of the real scientific paper) and they never said that.
Apparently, the axis that shifted is that of mass, called the Figure Axis, meaning the axis of symmetry in the Earth's mass distribution. We're still rotating in the same direction (defined by an axis which is not the Figure one), though.
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Newton still right!
Basic principles of mechanics remain sound!
Film at eleven.
The speed of the Earth's rotation changes every time I ride an elevator, too. (Please resist the temptation to make a fat joke here; it's too obvious to be worth the trouble.) On a more impressive scale, there's a significant and variable amount of angular momentum stored in the atmosphere. Changes in major air currents year over year (things like El Nino, for instance) can change the length of the day by close to a millisecond: hundreds of times more than this little earthquake.
~Idarubicin