Earth's Core Reverses Spin Direction

Core of Earth Allegedly Shifts its Rotational Pattern

In a groundbreaking discovery, an international team of researchers from Peking University and the University of Southern California have found that the Earth's inner core has changed its rotation direction around 2008. The study, published in the prestigious journal Nature, has shed light on this fascinating phenomenon that has been baffling scientists for years.

Between 2008 and 2023, the Earth's inner core was observed to be rotating slower, a phenomenon known as "subrotation". Interestingly, from 2003 to 2008, the inner core was rotating faster than the Earth's mantle, a phenomenon referred to as "superrotation".

John Vidale, the lead author of the study, expressed surprise at this change, stating that he was initially at a loss when he first saw the seismograms indicating this change. The researchers can only speculate about the consequences of this change in the Earth's core rotation.

The study reveals that the team determined the change in the Earth's core rotation by analyzing 121 recurring earthquakes around the Southern Sandwich Islands. They studied certain seismic waves that pass through the inner core, known as PKiKP waves, to determine the core's speed. The seismic measurements of the earthquakes, layered over many years, showed that the waves of the tremors arrived a little earlier or later at the measuring instruments, indicating a change in the core's speed.

The researchers' findings were supported by seismic measurements of Soviet nuclear tests in the 1970s. The observations "roughly" align with a 70-year cycle of Earth's inner core rotation model developed by other researchers, but the team found an irregular change in rotation speed in their measurements.

It's possible that the apparent backward movement of the inner core could alter the length of a day by fractions of a second, but it's very difficult to notice, as it's a matter of thousandths of a second. The inner core had slowed down for the first time in many decades, according to the study's findings.

The Earth's core, located about 5,000 kilometers below the Earth's surface, is mostly solid, made of nickel and iron. It's surrounded by molten rock, the outer core, the Earth's mantle, and the Earth's crust, which all rotate from west to east once a day. However, the Earth's core does not always rotate at the same speed as the rest of the Earth, which can make it appear as if its rotation direction is changing.

This fascinating discovery opens up a new avenue for research and understanding the complex dynamics of our planet. As Vidale himself admits, "This is a big deal. We've never seen anything like this before." The team's findings will undoubtedly spark further interest and investigation into the Earth's core and its role in shaping our world.