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Posted on 08/25/2005 8:20:46 PM PDT by neverdem
As the earth turns, the center of the earth turns even faster.
Confirming assertions first made in 1996, a team of geophysicists are presenting data in the journal Science today showing that the earth's inner core, a ball of solid iron larger than the moon, spins faster than the rest of the planet. Over a period of 700 to 1,200 years, the inner core appears to make one full extra spin.
That extra spin could give scientists information about how the earth generates its magnetic field.
The inner core, 1,500 miles wide, sits at the center of the planet, ensconced in a sea of hot liquid metal known as the outer core. With nothing to hold it in place, the inner core can rotate independently. Nearly a decade ago, two scientists at the Lamont-Doherty Earth Observatory of Columbia University said it did just that.
Other scientists, however, questioned the analysis, which was based on the speed of earthquake waves passing through the earth. Subsequent attempts to pin down the inner core's rate of spinning produced a wide range of answers. Some said it spun, but at a much slower rate than the Columbia scientists claimed. Others said they could find no sign that the core was out of step with the other parts of the planet. Some said it seemed to be spinning at a slower rate, not faster.
The same researchers who made the original claim, Paul G. Richards and Xiaodong Song, now a professor of geology at the University of Illinois, led the new research, which they said should remove any remaining doubts.
While it does not precisely pin down how much more quickly the core is spinning, Dr. Song said, "what this particular paper shows is it cannot be zero."
Gary A. Glatzmaier, a professor of earth...
(Excerpt) Read more at nytimes.com ...
Argh..that movie was 100% "teh suxor"
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Aging: Benefits Abound for Heart Surgery After 80
FReepmail me if you want on or off my health and science ping list. Anyone can post any unrelated link as they see fit.
Good one! LOL!
Thanks for the ping, neverdem.
Generation? Just how is gravity "generated"?
It's a little deeper than that. We're living on a big dirt clod (a bit damp in places) with a rock inside it and in turn the rock contains a ball of iron (but no succession of turtles.)
| gravity: my comment was about its generation.
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Read the article.
If you were referring to this paragraph...
Scientists believe they understand why the inner core might rotate at a different rate. The flow of rising and falling iron in the liquid outer core generates electric and magnetic fields, which push on the metallic inner core. "The thing is acting like a huge rotor in an electric motor," Dr. Richards said. "Except this one is running a billion amps."
...note that is has nothing to do with gravity, only magnetic fields.
Gravity is a function of mass. Exclusively. It is not "generated" by rotation, magnetic fields or the Great Pumpkin.
It's a weird phenomenon, but I'd have to see it to really believe it. And even then, just an optical illusion?
At first glance, this proposition, if true, would seem to be an astounding revelation.
But a closer look tells us that it is exactly what should be expected.
The moon, long ago, got to the point whare it always has the same face towards Earth. As time goes on, th Earth can be expected to slow down to do the same. As the Earth slows over eons, the excess angular momentum goes to the moon, whos orbit speeds up ever so slightly, taking it just a bit farther away.
If not for the moon moveing away, and eventually escaping, Earth would slow to the point where a lunar month equals a terrestrial day.
And the slowing effect that the moon has on the Earth is most apparent as a type of drag on the Earth's crust.
Scientific maverick's theory on Earth's core up for a test
SF Chronicle | Monday, November 29, 2004 | Keay Davidson
Posted on 12/05/2004 11:17:28 AM PST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1294934/posts
Hydrogen In The Core:Once a magma ocean was formed due to the blanketing effect of an impact-induced steam atmosphere of hundreds of bars, it absorbs most of H2O in the accreting planetesimals. Then the hydrogen is partitioned between the silicate melt and the molten iron that is sinking through the magma ocean to form the core. Thus, hydrogen is partitioned between the atmosphere, magma ocean and core... Two types of the protoatmospheres were proposed to produce the magma ocean: the primary atmosphere consists of the solar nebula gas, and the secondary atmosphere consists of the impact-degassed volatile... atmospheric hydrogen was oxidized by FeO in the magma ocean at its surface, transported through the magma ocean as H2O, and reduced by metallic iron in the deeper part of the magma ocean to form the iron-hydrogen alloy... On the other hand, if the magma ocean was formed through the blanketing effect of the impact-induced steam atmosphere, the hydrogen incorporation into molten iron may have decreased the mass and optical thickness of the atmosphere, and weakened the blanketing effect, because there was no nebula gas that supplies hydrogen to the atmosphere.
An Evidence For The State Of Lost Protoatmosphere
T. Okuchi, Y. Abe and H. IwamoriGetting to the problem of the core[T]he core cannot be made from iron alone because its density, determined by measuring the speed of seismic waves - is too low. This means there must be lighter elements there that are lowering its density. What is more, they have to be elements that are common in our solar system... "When you`re talking about possible impurities in the Earth`s core, the most likely things are the most common things like silicon, sulphur and oxygen".Earth’s core chemistry is silicon enhancedA team of scientists led by Jung-Fu Lin, a doctoral student in geophysical sciences at the University of Chicago, has found experimental evidence suggesting that the Earth's inner core largely consists of two exotic forms of iron instead of only one. These exotic forms of iron now appear to be alloyed with silicon. A previous study had once practically eliminated silicon as a candidate lighter element of the inner core... Seismologists have made further deductions about the characteristics of Earth's core from the way that seismic waves travel through Earth from earthquakes and explosives. "They noticed that there has to be about 10 weight percent of a lighter element in the outer core and anywhere from zero to 4 weight percent of a lighter element in the inner core" Heinz explained.Wobbles within wobblesA new theory proposes that iron-rich sediments are floating to the top of the Earth's core and sticking like gum to the bottom of the mantle, creating drag that throws the Earth's wobble off by a millimetre or two over a period of about 18.6 years... As the Earth spins on its axis the moon and sun tug on its bulging equator and create a large wobble or “precession”, producing the precession of the equinoxes with a period of 25,800 years. Other periodic processes in the solar system nudge the Earth, too, creating small wobbles - called “nutations” - in the wobble. The principal components of the nutation are caused by the Earth's annual circuit of the sun and the 18.6-year precession of the moon's orbit... An annual deviation that lagged behind the tidal pull of the sun first suggested to Buffett 10 years ago that strange processes may be going on at the boundary between the mantle, made up of viscous rock that extends 1,800 miles below the crust, and the outer core, which is thought to be liquid iron with the consistency of water. The inner core, made of very pure, solid iron, rotates along with the outer core, dragging the Earth's magnetic field with them... Because the Earth's core rotates about a slightly different axis than the mantle (due to the tug of the Sun and Moon), the core's magnetic field is dragged through the mantle, passing unhindered because the mantle does not conduct electricity. The porous, iron-containing sediment stuck to the mantle, however, would resist the rotation of the magnetic field, creating just enough tug to perturb the Earth's rotation.
probe planet's core
That's it for tonight (other than GGG digest pings).
Thanks for the links. Whatever happened to that guy's antineutrino experiment?
Que?
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So basically we're all living on a big dirt clod with a rock inside it. That's very reassuring.