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Earth's Core Spins Faster than Earth
Dreamwalkerofyore writes "The New York Times has an article on a recent affirmation that the earth's core rotates faster than the earth proper. From the article: '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... 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.'"
Given that the Earth's rotation is slowing down, isn't it immediately apparent that the liquid core must spin faster than the outside. It's just basic fluid dynamics. If apply a torque to the outside of a fluid filled region, the middle of that region will feel the effect last.
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If the core slows down due to friction with the mantle, will there be an effect on the magnetic field surrounding the Earth? Without the magnetic field, my understanding is that the Van Allen radiation belt will also not exist, and that in turn would expose the Earth to the full-on radiation of the Sun.
I'm no scientist, of course. But I wonder what the implications of the spinning core means. Also, how long would it take to stop spinning, or to develop a wobble?
There have been a slew of large earthquakes around the world lately. Could it be related?
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If we could cheaply generate fields that strong, we would not need nuclear power plants, we could generate all the energy we need using induction.
Well, according to Wikipedia why the reversal happens isn't well understood, so it very well could be. However there are some hints that this is the case in the Geomagnetic excursion page: I'd suggest looking for more authorative sources if you're truly interested.
Please begin rampant conjecture and wild speculation.
Don't mind if I do. From Geomagnetic reversal at wikipedia: Makes me wonder how geomagnetic reversals coincide with the speciation and evolution of our ancestors (or any animals). The extra radiation might not have killed them, but it certainly could have mixed things up, create higher then normal mutation rates. The last one was 780,000 years ago. Homo sapiens sapiens hasn't ever existed while there's been a geomagnetic reversal. It could be that by the time we came around, the mutations had died down to a normal rate.
I wonder what the rotation rate of Mars' core is. We know it's either liquid or solid and liquid (the latter being what Earth has), so it could have a difference, which would create a magnetic field. Only problem is, Mars doesn't have a magnetic field. However, Mars' field might also be hiding, as it does on Earth when changing the north and south poles which can take hundred to thousands of years. Now we've only been watching Mars with any sophistication for decades, which means Mars could have a field that's currently undergoing a reversal. If it isn't undergoing a reversal, and the two rotations are different, then it would prove enlightening on why that is the case.
The Earth's core also bounces from North to South. Not sure if it is a remnant of the colision that formed the Moon, or part of its conservation of momentum from the outer crust trying to change it's vector, the core being a giant defacto gyroscope.
Eventually I will post the math. =)
kulakovich
As another poster pointed out, sarcasm is often insightful.
What Smidge has pointed out (quite nicely, I must say) is that pretty much EVERY scientific theory/explanation can be trivialized in this matter. Let's face it, here's what ID boils down to:
1. The world, and everything in it, are complex. No one would argue this.
2. In trying to understand complex things, we might miss some details, or in fact most of the detail. Again, no one would argue this.
3. Because we can't claim a perfect, 110% understanding of something, there's simply no way we can ever understand any of it. Logical fallacy. However, because of this:
4. Therefore everything was created by God. Everything is the way it is because of God. Otherwise how could things be this way?
Oh, and
5. My theory's as good as yours, because I say so, and yours is quite frankly far to complicated to understand whereas mine is simple and therefore correct.
#3 is WHY ID is not 100% laughed at by people, and #5 is why it's accepted so widely.
Endless arguments over trivial contradictions in books written by ignorant savages to explain thunder in the dark.
what will be interesting is if someone can figure out not only the speed, but also the direction of the spin. There's no guarantee that the inner core is actually spinning along the same axis as the mantle/crust.
Sure there is: Fluid Friction. Only convection (like atmospheric or oceanic weather phenomena but at geologic time scales) and forces from the dynamo are likely to have any non-straightforward effect, and those will be minor deltas.
The basic mechanism is obvious: The planet is spinning. The core is molten while the crust is essentially solid. There is a massive moon, orbiting above synchronous orbit and creating tidal drag. The tidal drag slows the rotation and raises the moon's orbit. The tidal braking force is strongest at or near the surface of the planet and vanishes at the center.
With braking at the outer layers the core spins a tad faster, but in the same direction and (with the braking very small compared to the fluid fricton) ALMOST exactly at the same rate - the difference is about one turn in 300,000 (assuming the middle of the article's range).
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