Reply
Mon 1 Mar, 2010 10:21 pm
I just heard on the local news that the Chile quake shook the planet and moved it about three inches, shortening Saturday by so many tenths of a second. I did not hear the announcer plainly, but that's the gist of it.
I heard it shortened Saturday by millionths of a second.
T
K
O
@edgarblythe,
I didn't notice. Did they say what time it happened?
@roger,
Perhaps when you were in the tub.
CNN) -- The massive earthquake that struck Chile last week might have shifted the Earth's axis and created shorter days, scientists at NASA say.
The change is negligible, but permanent: Each day should be 1.26 microseconds shorter, according to preliminary calculations. A microsecond is one-millionth of a second.
A large quake shifts massive amounts of rock and alters the distribution of mass on the planet.
When that distribution changes, it changes the rate at which the planet rotates. And the rotation rate determines the length of a day.
"Any worldly event that involves the movement of mass affects the Earth's rotation," Benjamin Fong Chao, of NASA's Goddard Space Flight Center in Greenbelt, Maryland, said while explaining the phenomenon in 2005.
Scientists use the analogy of a skater. When he pulls in his arms, he spins faster.
That's because pulling in his arms changes the distribution of the skater's mass and therefore the speed of his rotation.
Richard Gross, a geophysicist at NASA's Jet Propulsion Laboratory in Pasadena, California, used a computer model to determine how the 8.8-magnitude quake that struck Chile on February 27 might have affected the Earth.
He determined that the quake should have moved the Earth's figure axis about 3 inches (8 centimeters). The figure axis is one around which the Earth's mass is balanced. That shift in axis is what might have shortened days.
Such changes aren't unheard of.
The 9.1-magnitude earthquake in 2004 that generated a killer tsunami in the Indian Ocean shortened the length of days by 6.8 microseconds.
On the other hand, the length of a day also can increase. For example, if the Three Gorges reservoir in China were filled, it would hold 10 trillion gallons (40 cubic kilometers) of water. The shift of mass would lengthen days by 0.06 microseconds, scientists said.
@edgarblythe,
No wonder I never have enough time to finish things these days.
It shortend not just Saturday, but every day from then on. And each major earthquake does. I heard the same on the news today. Take about awesome power!
@littlek,
littlek wrote:It shortend not just Saturday, but every day from then on. And each major earthquake does.
I read that it could have the opposite effect and lengthen days as well. Pretty awesome either way though.
@edgarblythe,
I am sorry but I think you are a rumor-monger
To give an idea of how little it changed the length of day, the change in the velocity of the Earth’s rotation slows by 1000 times that amount (on the order of 1/1000 of a second) every Winter (Northern Winter); to speed by up in spring.
@findingsolutions,
There's a rumor that a poster calling him/herself findingsolutions has a reading comprehension problem. But it could be wrong.
@littlek,
Shortened! Hey, does that solve the global warming thingy?
It's nothing compared to the effect of dams. I heard that water piled up in dams in the northern hemisphere which would run back into the Pacific normally, by which I mean if we weren't here, has bigger effects that that.
But no need to worry. You just set your clock once every 24 hours and it evens out. If you don't look at the clock when you wake up in the morning it doesn't make any noticeable difference.
It reminds me of the famous headline-- "Earthquake in Chile--Not Many Dead."
The moon does worse. It has taken us from a six hour day to our current 24, so we are getting more time in the day overall.
@roger,
No.
Nor does not having daylight saving.
Fewer Rats though....