Unraveling the Mystery of Earth’s Magnetic Field with Hot Rock Blobs
Earth’s magnetic field extends tens of thousands of kilometres into space
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Recent research has shed light on the enigmatic presence of two massive hot rock blobs near Earth’s core, potentially influencing the planet’s magnetic field and causing it to exhibit slight irregularities over millions of years.
These peculiar continent-sized regions of rock, located beneath Africa and the Pacific Ocean, have puzzled scientists due to their distinct properties that slow down the passage of seismic waves. While the exact composition of these blobs remains elusive due to their depth, researchers have hypothesized that they play a crucial role in Earth’s magnetic field dynamics.
Leading the investigation, Andrew Biggin and his team from the University of Liverpool delved into the relationship between these hot rock blobs and the planet’s magnetic field. By analyzing ancient volcanic rocks that retain records of Earth’s magnetic field orientation over extensive periods, the researchers conducted simulations to understand how heat transfer within the core shapes the magnetic field.
Surprisingly, the simulations revealed that the presence of the hot rock blobs aligns most closely with the observed changes in Earth’s magnetic field over time. This suggests that the blobs have maintained higher temperatures compared to their surroundings for hundreds of millions of years, influencing heat flow between the core and mantle and contributing to the stability of the magnetic field.
Contrary to previous assumptions of symmetry in Earth’s magnetic field, the team’s findings indicate persistent deviations and asymmetries that can be attributed to the influence of these anomalous rock formations. This discovery not only enriches our understanding of the planet’s magnetic history but also offers insights into the evolution of Earth’s deep structures.
Looking ahead, the researchers speculate that similar temperature differentials may exist in the upper core, potentially detectable through seismic wave analysis. However, challenges in accurately mapping variations within the core, as noted by Sanne Cottaar from the University of Cambridge, present significant hurdles in confirming these hypotheses.
