Changes in the Earth's inner core affect time
Do you feel like the day is dragging on endlessly? Scientists confirm that the length of the day on Earth is increasing, and say that the rotation of the inner core of our planet is to blame. Earth's dense inner core is now moving backward relative to the surface. Researchers say this could change the length of the day by fractions of a second.
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If the days seem to be dragging on like never before, it may not be your fault alone. boring job, writes the Daily Mail. A new study finds that changes in the Earth's inner core may be causing the day to become longer.
According to a team of scientists from the University of Southern California, the dense metallic core of the Earth is currently shifting relative to the surface of the planet. After studying earthquake data, they found that the inner core began to slow down around 2010 and is now moving in the opposite direction, subtly affecting the Earth's rotation in space.
However, don't expect to have more time in the day just yet, as the researchers say the changes may be very subtle.
The Earth is made up of four main layers: the crust, the mantle, the outer core, and the inner core. says the Daily Mail. At the very center of the planet, 3,000 miles (4,800 km) below our feet, lies the inner core — a superheated ball of solid iron and nickel about the size of the Moon. Because the outer core is entirely liquid, this dense metal sphere is free to rotate under the influence of the Earth's magnetic field and the gravitational influence of the outer layers.
For many years, many scientists believed that the inner core rotated faster than the Earth's surface. However, Professor John Vidale, an Earth scientist at the University of Southern California, says the core has now slowed down and begun to move in the opposite direction.
"The dance of the inner core may be even more lively than we previously thought until now,” he said.
Unable to directly observe the Earth's inner core, researchers relied on data collected from seismic events.
In particular, Professor Vidale and his co-authors focused on events called repeating earthquakes — seismic events that occur in in the same location, resulting in identical patterns in recordings called seismograms.
In addition to the 121 natural events recorded in the South Sandwich Islands, the researchers also used man-made events, such as the twin Soviet nuclear tests between 1971 and 1974.
Because seismic events send shock waves across On the Earth, the state and location of each layer will slightly change the waveform that scientists record.
When the repeating waveforms match, this reveals moments when the inner core is in exactly the same position relative to the outer layers of the Earth.
The researchers found sets of seismograms in which repeated earthquakes occurred, changed, and then coincided again several years later.
For example, the data showed that the earthquake recorded in March 2003 was slightly different from the 2009 earthquake in that same location, but was identical to the earthquake recorded in 2020.
This shows that the inner core moved relative to the surface between 2003 and 2009, only to return to its previous position by 2020 .
This means that the inner core must have been rotating forward relative to the surface until some time in 2010, after which it slowed down and began to move backward.
Professor Vidale says: “When I first saw the seismograms that hinted at this change, I was puzzled. But when we found two dozen more observations pointing to the same pattern, the result was inevitable. The inner core has slowed down for the first time in decades.»
This slowdown may be caused by the churning of the liquid iron core, which generates the Earth's magnetic field, as well as gravitational pulls from unusually dense regions of the mantle.
Although The effects this will have are almost impossible to predict, Professor Vidale says it could result in a very small change in the length of the day.
He says: "It's very difficult to notice, it happens on the order of a thousandth of a second, almost lost in the noise of the seething oceans and atmosphere.»