THE CENTER OF THE EARTH IS WEIRD
From Astronomy Picture of the Day
By Elaine Meinel Supkis
Well, thanks to the earth shaking like a dog with fleas, the Boxing Day Earthquake has rung the earth like a great iron bell. And the vibrations have traveled back and forth and earthquakes galore, allowing scientists a hopefully once in a lifetime chance to study the belly of this beast: the earth's core. The research so far is awesome.
From Yahoo News:
WASHINGTON - The giant iron ball at the center of the Earth appears to be spinning a bit faster than the rest of the planet.Not only did the tremendous earthquake last December cause tsunamis, it slowed down the planet. In addition, in today's news is the fact that the tsunami actually traveled all the way around the planet, hitting South America! This is another reason for us to think of our planet as one home, you know.
The solid core that measures about 1,500 miles in diameter is spinning about one-quarter to one-half degree faster, per year, than the rest of the world, scientists from Columbia University's Lamont-Doherty Earth Observatory and the University of Illinois at Urbana-Champaign report in Friday's issue of the journal Science.
The spin of the Earth's core is an important part of the dynamo that created the planet's magnetic field, and researcher Xiaodong Song said he believes magnetic interaction is responsible for the different rates of spin.
The faster spin of the core was proposed in 1996 by two of the current study's authors, Paul Richards of Lamont-Doherty and Song, now an associate professor at Illinois.
The researchers studied the travel times of earthquake waves through the Earth, analyzing what are called couplets. Those are earthquakes that originate within a half-mile or so of one another but at different times.
They analyzed 30 quakes occurring in the South Atlantic and measured at 58 seismic stations in Alaska and found differences in the travel times and shape of the waves, indicating differences in the core as the waves passed through the center of the Earth.
Analyzing those differences, they calculated that the core is spinning slightly faster than the rest of the planet and is a bit lumpy.
That solid inner core is surrounded by a fluid outer core about 4,200 miles across.
From 2003 Geological Society news;
Our planet is alive, everyone. Like you and me. It moves as we saw this year. It does many things regular planets don't do. Mars is dead. So is the moon.
There's a small problem with Earth's magnetic field: It should not have existed, as the geological record indicates it has, for the past 3.5 billion years.
Motions in the Earth's molten iron core generate convection currents that which produce the field. Many sources of heat drive these currents, but the known sources seem inadequate to maintain the field this long.
In 1971 University of Minnesota geology and geophysics professor Rama Murthy theorized that radioactive potassium in the core could supply additional heat, but researchers investigating that claim have been unable to obtain reliable experimental data. In a paper published in today’s (May 8) Nature, Murthy presents experimental evidence for his idea and shows why other researchers have been unable to corroborate it.
The work helps explain how Earth has maintained its magnetic field, which shields the planet from harmful cosmic rays and the constant stream of charged particles from the sun known as the solar wind.
“Earth is losing energy from its surface at a rate of about 44 trillion watts” Murthy says. “About 75% is heat from the mantle, and 20 to 25% from the core. Measurements of cooling at the core-mantle boundary show too much loss for a core to maintain heat and a magnetic field for 3.5 billion years.”
But if radioactive elements such as potassium, and perhaps uranium and thorium, also exist in the core, the heat from their radioactivity could keep the core hot enough to move and maintain the magnetic field," he said.
What lies in our heart here is a dynamic system just like that which lies in the very center of the sun. The fact that the core travels at a higher speed than the rest of the earth is very interesting. The fact that our magnetic sphere suddenly switches direction (lordy, pray it doesn't happen soon, though, since it is weakening, maybe it better!) is an oddity, too. The hyperactivity of our old planet is actually probably pretty improbable and one might say, it is "Intelligent Design" but according to the NASA picture above, our magnetic sphere that keeps us alive looks like the Spaghetti monster, doesn't it?
The next step, says Murthy, is to study how potassium moves into core material at higher temperatures and pressures, closer to conditions deep in Earth's mantle. He says similar experiments should be done to see whether uranium and thorium could also have moved into the core during the planet's formation. As the sources of Earth's inner heat get sorted out, Murthy says the new knowledge will refine ideas about how continents drift. Continents are part of Earth's crust, or thin outer layer. They are thought to move around by convection currents in the mantle, but whether those currents exist in the whole mantle or just the upper part is still an open question, Murthy says.Well! If the core is a bumpy object of tremendous density (hello, mini-black holes!) with an inner core as well as the outer mass, then there is the mantle with is so heated up it is tremendously hot, isn't it? Hot enough to glow in the dark, a mini-sun covered by a crust of earth and that is mostly covered with water, yes, water that cools off the mantle's outpourings forming land masses like Hawaii.
This friction and turbulance is barely understood right now, as we collect data, we learn more and more and the old Chinese image of the Dragon sleeping under our feet or the Norse Gunnigunap, the great dragon ensnaring the lands, seems apt, no?
Or our beloved Spaghetti Monster. Destructive and yet charming. We must burn offering to him but then, that might enrage him. Let's cook pasta and salute our true Creator!
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