The Crystals at the Center of the Earth

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[Paranormal_Research] Fw: The Crystals at the Center of the

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Fri, 14 May 2010 10:06:53 -0400

 

 

 

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http://www.wired.com/wiredscience/2010/05/crystals-earth-core/

 

 

 

The Crystals at the Center of the Earth

 

 

By Alexis

Madrigal 

May 11, 2010  | 

12:55 pm  | 

 

 

 

 

Seismic waves traveling between Earth’s poles move faster

than those moving east-west, and now scientists think they may know why.

The iron alloys in the solid inner core of the Earth appear

to have crystallized in such a way that it’s easier for energy to

pass on the north-south axis than on the east-west, as described in a

new study led by Maurizio Mattesini, a geologist at the Universidad

Complutense de Madrid, which appeared in the journal Proceedings

of the National Academy of Sciences.

“The structure of the atoms looks different in one

direction than the other,†explained Norm Sleep, a Stanford geologist

who was not part of the new study,

In the textbooks of yore, the Earth’s inner regions like

the mantle and core were presented as simple, fairly homogeneous

regions. But the geology of the core is turning out to be much more

complex as scientists make use of more and better seismographs to

generate better data about how seismic waves travel through the planet.

The outer core is composed mostly of liquid iron. The inner

core is solid ball about 750 miles in diameter, or a little less than

the maximum width of the state of Texas, which formed as the Earth

cooled over geologic time, said David Stephenson, a geologist at

CalTech.

“The center of the earth is literally a crystal,†said

Stephenson. Over time, it grew and now is no longer a single crystal

but an aggregate of them.

 

In the mid-1990s, geologists began to notice an interesting

thing. Seismic waves traveling north-south were reaching their

destinations about 3 percent faster than waves moving along east-west

paths.

“It’s one of these things that’s been detected for

some time but kind of why it occurs has been somewhat of a puzzle,â€Â

Sleep said. They didn’t know why, but then again, the middle of the

globe is perhaps the most difficult place to gather data on Earth.

The new paper suggests that as the crystals formed, they

received a particular alignment. That alignment, known as anisotropy,

makes it easier for waves to travel in one direction than the other.

The most significant thing about the new paper, Stephenson

said, is that the researchers were able to match up the results that

seismologists have been getting on the speed of seismic waves through

the core with new laboratory tests with particular kinds of iron

crystals.

Image: NASA

“Hemispherical anisotropic patterns of the Earth’s inner

core†by Maurizio Mattesinia, Anatoly B. Belonoshkob, Elisa Buforna,

MariÃŒÂa RamiÃŒÂreza, Sergei I. Simakc, AgustiÃŒÂn UdiÃŒÂasa, Ho-Kwang

Maod, and Rajeev Ahujae in the Proceedings of the National Academy

of Sciences DOI: 10.1073/pnas.1004856107