Earth's Inner Core Rotation Reversal: Scientists Explain the Phenomenon and Its Impact

Recent research reveals that the Earth’s inner core has slowed down to the point of appearing stationary relative to the surface before moving in the opposite direction. Based on seismic wave analysis from hundreds of earthquakes, scientists found that since around 2009–2010, the inner core has been rotating slower than the Earth’s mantle and crust. Although often referred to as the ‘Earth’s core rotating in reverse’, this change only occurs in the relative rotation speed and is a natural process that poses no threat to human life. The Earth’s inner core is a solid layer composed of iron and nickel, located more than 5,000 kilometres beneath the surface. According to Nature Geoscience, its rotational changes are thought to be influenced by the magnetic field interactions of the liquid outer core and the gravitational forces of the Earth’s mantle, causing its spin speed to change as part of a natural cycle lasting several decades. So, will the change in the inner core’s rotation affect life on the Earth’s surface? Scientists confirm the impact is almost imperceptible. The change only causes a very slight variation in the length of a day on Earth, around a fraction of a millisecond. This figure can only be detected using high-precision scientific instruments and will not affect daily human activities. The research also found no evidence that the slowing or reversal of the inner core’s rotation can trigger earthquakes, volcanic eruptions, or other natural disasters. In other words, this phenomenon is not a sign of impending major changes to the Earth’s condition, but rather part of the normal dynamics of the planet’s interior that have been ongoing for millions of years. Although it has no direct impact on humans, research on the Earth’s inner core is considered important for understanding how the planet works from its deepest parts. The inner core’s movement is linked to the dynamics of the outer core, which generates the Earth’s magnetic field, a natural shield that protects the planet from harmful solar radiation. Scientists hope that further research with longer seismic data will reveal more information about the relationship between the inner core’s rotation, the magnetic field, and minor changes in the Earth’s rotation. These findings are expected to enrich the understanding of the Earth’s evolution while helping to explain various geological processes that remain a mystery to this day.