For the first time in decades. Scientists have explained why days are now longer than before

A new study has shown that changes in the Earth's inner core can increase the length of days. According to a team from the University of Southern California, the Earth's dense metal core is rotating relative to the planet's surface.

In other words, scientists have confirmed that the length of days on Earth is increasing, and they say that the rotation of our planet's inner core is to blame. By reviewing earthquake data, they found that the inner core began to slow down around 2010 and is now moving backwards, imperceptibly affecting the Earth's rotation in space, MailOnline writes.

Don't expect to gain more hours in the days, however, as researchers say the changes will be hard to notice.

The Earth is made up of four main layers: the crust, the mantle, the outer core, and the inner core. At the very center of the planet, 4,800 kilometers beneath our feet, is the inner core, a superheated ball of solid iron and nickel about the size of the moon. Because the surrounding outer core is completely liquid, this dense metal sphere can rotate freely under the influence of the Earth's magnetic field and the gravitational pull of the outer layers.

For many years, many scientists believed that the inner core rotates 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 started to move backwards.

"The dance of the inner core may be even more lively than we know so far," he said.

Unable to directly observe the Earth's inner core, the researchers relied on data collected from seismic events. In particular, Prof. Vidale and his co-authors focused on events called recurrent earthquakes - seismic events that occur in the same location to create identical patterns in records called seismograms.

As seismic events send shock waves through the Earth, the condition and location of each layer will slightly alter the waveform that scientists record. When the shapes of repeated waves match, it reveals moments during which the inner core is in exactly the same position relative to the outer layers of the Earth.

The researchers found that the sets of seismograms on which a recurrent earthquake occurred changed and then matched again after a few years. For example, the data showed that the earthquake recorded in March 2003 was slightly different from the 2009 earthquake at the same location, but identical to the earthquake recorded in 2020. This indicates that the inner core moved relative to the surface between 2003 and 2009 to return to the same position by 2020.

This means that the inner core must have been rotating forward relative to the surface until some time in 2010, when it slowed down and started moving backward. Prof. Vidal said: "When I first saw the seismograms that hinted at this change, I was confused. But when we found two dozen more observations that signaled the same pattern, the result was inevitable. The inner core had slowed down for the first time in decades."

This slowdown could be caused by the churning of the liquid iron core that generates the Earth's magnetic field, as well as gravitational forces from the extremely dense regions of the mantle. Although the effects this will have are almost impossible to predict, Professor Vidale says it could change the length of the day by a very small amount: "It will be very difficult to notice, in thousandths of a second, almost lost in the noise of the stormy oceans and atmosphere."

Only verified information is available on our Telegram channel OBOZ.UA and Viber. Do not fall for fakes!