Magnetic field: Two giant underground bubbles may be causing a crack in the Earth’s magnetic field – it has been increasing in size for at least two centuries and is now beginning to divide. Scientists suspect that this change, known as the Magnetic Anomaly of the South Atlantic (AMAS), is caused by two bubbles of dense material discovered in the Earth’s mantle recently. Each of these (called by NASA “dent”, or teeth in literal translation) is millions of times larger than Mount Everest.
Research indicates that these bubbles, also known by the acronym LLSVPs (large low-shear velocity fields), may be the remains of Theia, an ancient planet the size of Mars that is believed to have collided with Earth around 4.5 billions of years ago. The problem is that this gap, located between South America and South Africa, has been wreaking havoc on satellites and spaceships passing over it. And it gets worse: it interferes with the levels of solar radiation that the planet receives and increases the amount of solar particles that pass through the magnetic field, which can cause malfunctions in computers and circuits.
The Earth’s magnetic field is generated by the swirling iron in the outer core of the planet, where the warmest material rises to the partially solid mantle and is replaced by denser material – a process called convection. Scientists believe that the strange change in the magnetic field is caused by something huge that is disrupting this process under the Atlantic Ocean. As it turned out recently, the two LLSVPs could be significant enough to affect these convection currents, as the geochemist Qian Yuan proposed, leading the study on Theia’s remains.
Questioning the theory
Although the possibility that the cause for the change in the Earth’s magnetic field is in fact the remnants of the planet that gave rise to the moon is very seductive, there are still unanswered questions, and even conflicting with Yuan’s theory. Geophysicist Christopher Finlay of the Technical University of Denmark points out that the same weakness in the magnetic field does not occur above the Pacific Ocean, where part of one of the bubbles is located.
Although for now it is only speculation, theories like this create the possibility of further in-depth studies that, in turn, can lead to discoveries about the magnetic field that surrounds our planet and directly influences our lives.