Scientists from Peking University, Yi Yang and Xiaodong Song, have published a paper of research observing changes in the length of Earth’s day and magnetic field, which they believe implies changes in the Earth’s core. Their seismic observations from 1964 to present suggest that the inner core goes through a 70-year oscillation, slowing down and then spinning in the opposite direction. Song had previously discovered the core’s rotation in a 1996 study by studying seismic waves from earthquakes.
What causes the Earth’s core to rotate?
The Earth’s core is believed to be made up of the inner core, which is about 70% of the moon’s radius and primarily composed of iron, and the outer core, a liquid mixture of iron and nickel. The inner core is a solid ball of metal located about 5,000 km below Earth’s surface and estimated to be about the same size as Pluto and as hot as the surface of the Sun. The potential change in the inner core’s rotation could have implications for Earth’s magnetic field and the planet as a whole, but it is not expected to result in a catastrophic event.
The mantle, which makes up 84% of the Earth’s volume and acts like caramel, and the differences between the mantle, outer core, and inner core cause the core to spin. As the outer core cools and fuses with the inner core, heat is released, generating the Earth’s magnetic field, and this combined with the gravity of the mantle causes the inner core to spin. The existence of the Earth’s core was first discovered in 1936 by Danish seismologist Inge Lehmann, who noticed seismic waves reflecting off of a solid object.
Is the stopping of Earth’s core putting us in danger?
According to recent research, The Earth’s inner core appears to have stopped spinning in the last decade, and may now be reversing its spin direction. The researchers state that this slowing and change in direction could be related to fluctuations in sea levels and the length of days, which occur every 70 years. The findings suggest that this is a natural part of the core’s cycle and is not necessarily a cause for concern,
The speculation of Earth’s inner core potentially reversing its course may sound concerning, however, there is no evidence to suggest it will result in any catastrophic event. This planetary spin cycle may have been happening for a long time and is a natural part of Earth’s innermost core. The researchers aim to deepen our understanding of this realm and its relationship with the rest of the world.
According to scientists, the inner core likely crystallised from a molten metal mixture after the Earth’s internal heat had cooled enough. “The existence of a solid iron ball floating in the centre of the Earth is a mysterious and fascinating phenomenon,” noted John Vidale, a seismologist from the University of Southern California.
The exact cause of the erratic behaviour of seismic waves reaching Earth’s inner core remains uncertain and is still being researched. There are several models being considered, including the possibility of Earth’s innermost layer wobbling, or the ferrous nucleus having a changing surface that twists the seismic waves. Despite these theories, there is still disagreement and the true explanation of this deep and inaccessible realm may never be fully understood. The exact reason behind the erratic voyages of seismic waves that reach the Earth’s inner core remains elusive and may never be fully understood. However, Dr. Vidale remains optimistic and believes that eventually, the pieces of the puzzle will come together.