lunes, 14 de marzo de 2011
The Day the Earth Sped Up
The massive earthquake that hit Japan sped up Earth's spin by a microsecond and tilted the axis by several inches.
The shift happened when massive amounts of the planet's crust tumbled inside a 250-mile long crack that opened up six miles beneath the Pacific Ocean.
Changes in Earth's tilt are associated with ice ages.
This weekend, it wasn't just the shift to Daylight Saving's Time that reset our clocks. Mother Nature tweaked time by speeding up Earth's spin a bit in response to the killer earthquake that rocked Japan on Friday.
"There was a redistribution of an enormous amount of the Earth's crust," theoretical physicist Michio Kaku, with the City College of New York, told Discovery News. "It actually shortened the time of the day, and also shifted the axis of the Earth."
The 8.9-magnitude quake -- the fifth largest in recorded history -- shaved about one-millionth of second off our day and tilted the planet's axis by several inches.
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Kaku says the phenomenon is similar to what happens when a dancer folds in his or her arms and speeds up in a spin.
The shifting of tectonic plates beneath the Pacific Ocean opened up a crack about 250 miles long, causing a good portion of Earth's crust to tumble inside.
"We know how much the Earth contracted as consequence of that, then you do the math," Kaku said.
While the speeding up of Earth isn't expected to have any immediate or long term impacts, the tilt of the axis might.
"There is still a scientific debate as to what causes ice ages," Kaku said. "The leading theory is that there are tiny perturbations in the axis of the Earth as it turns around the sun that accumulate with time. These small shifts, this wobbling of the axis of the Earth may in fact cause ice ages."
"Every century, we have several of these monster earthquakes so it's hard to estimate exactly how much of an impact this earthquake would have on an ice age, for example," Kaku added.
The earthquake was the most powerful to hit Japan since official record-keeping began in late 1800s, says the U.S. Geological Survey.
It struck about 80 miles off Japan's east coast, roughly 240 miles northeast of Tokyo, at a depth of six miles. The death toll from the earthquake, a massive tsunami that followed, and an ongoing serious of aftershocks is expected to reach in the thousands.