You would think that the one we live on is the best planet in the universe.
That is part of the problem, living on it. The surface area of Earth is 500 million square kilometers. All that stuff is deep inside the planet where we can't possibly get to it to study.
We have a lot of knowledge about what is happening under our feet. A lot of what is happening is not normal. The Earth's inner core spins at a slightly different rate than the rest of the planet. It moved ahead of the rest of the planet by about a degree per year, which meant it would go by the outer part of the planet every few hundred years. It's called super rotation.
This isn't the case, according to a new paper. The core superrotated from 1971 to 1974 by less than previously thought. Between 1969 and 1971 the core slowed so much that it spun slower than the rest of the planet above it. It moved around a bit. The core seems to be able to speed up and slow down. There's a link to paper.
The core of the press release is not true. The core spun in the other direction. It went from moving slowly ahead of us to moving slowly behind as it moved closer to the mantle. If you were able to measure the core's spin in space, you'd see it was the same as the rest of the world. The rotation speed changed. It is similar to passing a car on the highway, but to someone on the ground it is moving slower than you are. Perspective makes a difference here.
How did they come up with this? There are nuclear bombs.
This wasn't a real life recreation of The Core. When the waves hit the solid inner core they scatter, reflected andbent, and the inner core rotation affects this scattering in a number of ways.
Nuclear bombs were tested by the U.S. and U.S.R. The Cannikan test in 1971 was roughly 1 and 4 megaton and the Milrow test in 1969 was roughly 1 and 4 megaton. The scientists used data from the time to show that the inner core was sub rotating at that time.
They used U.S.S.R tests to show that the inner core superrotated. They found that the inner core rotation slowed down and sped up when they put all their data together.
What's the reason? Iron and nickel make up the inner core. There is a dichotomy between the western and eastern hemispheres when it comes to the distribution of hexagonal iron crystals. The gravity from the inner core isn't smooth and the different hemispheres tug on the Earth's mantle in different ways Slowing the core down and speeding it up can be done by this. This is complex and not fully understood. We are talking about the structure of a ball of iron that is 2,500 km across and buried under a shell of molten iron that is 2,200 km thick. It's amazing that we know everything about it.
The length of the day is shortened and increased by a couple of tenths of a second every six years. The scientists have found that the periodic change in the inner core can explain this. The change is small, but to Earth scientists that is huge.
Much of the Earth's interior is still shrouded in mystery. The length of day, our magnetic field, and many other things are affected by it. We need to learn more to understand our planet.
The Emerald Tablet could be paraphrased as below.
I savaged the science of the movie The Core when I reviewed it for my website. I was a bit premature, and there is a very fun story to tell.
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