Earths twin cores may have sparked off plate tectonicsJanuary 7th, 2009 - 2:25 pm ICT by ANI
Washington, Jan 7 (ANI): Scientists have come up with a new theory that suggests the Earth has not one but two inner cores, which may have given rise to plate tectonics, and explain why the planet remains hotter today than it should be.
According to a report in Discovery News, the idea stems from an ancient, cataclysmic collision that scientists believe occurred when a Mars-sized object hit Earth about 4.45 billion years ago.
The young Earth was still so hot that it was mostly molten, and debris flung from the impact is thought to have formed the moon.
Haluk Cetin and Fugen Ozkirim of Murray State University have suggested that the core of the Mars-sized object may have been left behind inside Earth, and that it sank down near the original inner core.
There, the two may still remain, either separate or as conjoined twins, locked in a tight orbit.
We have no solid evidence yet, and were not saying 100 percent that it still exists, Cetin said. The interior of Earth is a very hard place to study, he added.
The ancient collision is a widely accepted phenomenon.
But most scientists believe the incredible pressure at the center of the planet would have long since pushed the two cores into each other.
Still, the inner core is a mysterious place. Recently, scientists discovered that it rotates faster than the rest of the planet.
Also, a study last year of how seismic waves propagate through the iron showed that the core is split into two distinct regions.
Beyond that, little is known.
But, according to Cetin and Ozkirim, a dual inner core can explain the rise of plate tectonics, and help explain why the planet remains hotter today than it should be, given its size.
If this is true, it would change all Earth models as we know them, Cetin said. If not, and these two cores coalesced early on, we would have less to say, but it could still be how plate tectonics got started, he added.
Based on models of Earths interior, Cetin thinks the two cores rotate in opposite directions, like the wheels of a pasta maker.
Their motion would suck in magma from behind and spit it out in front. If this motion persisted for long enough, it could set up a giant current of circulation that would push plates of crust apart in front, and suck them down into the mantle in back.
Friction generated by the motion would keep the planet hot. (ANI)
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