The Earth Moves Under Our Feet

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Earth
Courtesy of kristian fagerström (Flickr CC0)

There’s something special about the Earth. It’s not just home to 7.8 billion people. University of Southern California (USC) scientists believe that the Earth’s inner core oscillates, spinning, turning, and swirling underfoot.

It’s a little-known fact, but even standing on its surface, the Earth is moving. Sometimes it moves quickly, spinning so fast that nobody can tell which direction it is turning. But, sometimes, it moves more slowly, like a great beast waking from a long slumber.

In a recent paper published in Nature, scientists discovered that the Earth’s inner core isn’t fixed and moves about a mile every six years. While this might seem insignificant, it confirms a theory that the Earth is moving more slowly than previously thought. But the data presented in the study has some limitations. While the findings are intriguing, they don’t prove that the Earth is moving as fast as scientists had previously claimed.

The Earth’s inner core is spinning faster than the planet’s surface, a process known as super-rotation. Previous studies had estimated the speed of super-rotation to be one degree per year, but the new research shows that it is only 0.1 degrees per year. Despite this new finding, scientists must rely on indirect data to explain the changes occurring beneath our feet.

Earth
Courtesy of bluesbby (Flickr CC0)

Changing day length might signify that the Earth is changing its position. The researchers believe this may be because the inner core rotates faster than the surface. The new study has implications for our understanding of the planet’s rotation and daily schedule. The researchers say the new theory explains the variations in day length over the past several decades. However, researchers admit that the results are preliminary.

The Earth’s inner core is a dense, hot ball that scientists cannot directly observe. It is also solid iron, making it difficult to study now. Using seismic data from 1969 to 1974, researchers built a computer model of the core’s movements. They concluded that the inner core oscillates back and forth about 1.25 miles every six years, and this movement is due to the Earth’s rotational speed.

Postdoctoral scholar Vidale and previous studies have shown that the Earth’s inner core is rotating at a slower speed than previously thought. Researchers have determined that the rotation of the inner core was in a reversed direction, and it is sub-rotating approximately a tenth of a degree per year. They applied the same technique to study the Soviet atomic tests conducted in the Novaya Zemlya archipelago.

The core of the Earth is hotter than the sun, oscillating more than a mile every six years. Researchers have been studying this phenomenon for decades. It could help explain the variations in the length of the Earth’s day. The Earth’s rotational movement may explain the variations in the days people experience. Vidale said:

We went into this expecting to see the same rotation direction and rate in the earlier pair of atomic tests, but instead we saw the opposite. We were quite surprised to find that it was moving in the other direction.

Written by Janet Grace Ortigas
Edited by Sheena

Sources:

PHYS: The Earth moves far under our feet: A new study shows that the inner core oscillates
Science Daily: The Earth moves far under our feet: A new study shows the inner core oscillates
Climate Change: The Earth moves far under our feet: A new study shows the inner core oscillates

Featured and Top Image Courtesy of kristian fagerström’s Flickr Page – Creative Commons License
Inset Image Courtesy of bluesbby’s Flickr Page – Creative Commons License

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