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Wednesday, March 3, 2010

Chile earthquake alters Earth axis & makes days shorter


The recent 8.8-magnitude Chile earthquake has caused massive devastation in the South American nation. Recovery efforts are already underway amidst turmoil and looting that required military intervention, but here’s something interesting that has nothing to do with money and property. According to media outlets like CNN, NASA scientists are speculating that the massive Chile earthquake has altered Earth’s axis. It’s currently a theory and not instant money, but think about what this could mean.

We aren’t talking about a minor trembler here. Magnitude 8.8 is a massive earthquake. If NASA is correct and the Earth’s axis has shifted, then the planet’s rotation could be permanently affected by the redistribution of mass. Scientists believe this means shorter days, but only slightly: 1.26 microseconds shorter, they estimate. One microsecond is one-millionth of a second, which is not enough time to mess with your beauty sleep or make you late for work. But the global impact is still amazing to contemplate.
Earth’s rotation determines the length of our days
How fast does the Earth rotate? NASA provides the following basics: Earth rotates on its axis at just over 1,000 miles per hour. Its rotation around the sun (which affects seasonal changes in climate) occurs at about 67,000 miles per hour. Now you know.
Benjamin Fong Chao of NASA said in 2005 that “Any worldly event that involves the movement of mass affects the Earth’s rotation.” A popular analogy NASA uses is a figure skater. When she pulls her arms close to her body, she spins faster. The redistribution of mass is similar to what scientists believe happened after the Chile earthquake. The Earth’s axis has changed because of the mass shift. Richard Gross of NASA’s Jet Propulsion Laboratory in Pasadena, California speculated to the media that the axis could have shifted about three inches.
The Chile earthquake 2010 isn’t unique in its effect
Back in 2004 when a 9.1-magnitude earthquake made a gigantic tsunami in the Indian Ocean, our days shortened by 6.8 microseconds. But the converse of shortened days would be if a mass shift slowed the Earth’s rotation on its axis. CNN gives an example of the Three Gorges reservoir in China. If it were to be filled in by 10 trillion gallons of water, that mass would change the rotation to the point where our days would be .06 microseconds longer. An impossible-to-discern quick loan to our days, but scientists would know based on the math involved.
So when you think of the Chile earthquake and the Earth’s axis, think of the human impact – and how many fractions of a microsecond less per day they may have to reconstruct their lives before the cataclysm.

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