A team of geophysicists say that an enormous mass shifted deep beneath the Earth\u2019s surface 18 years ago.<\/p>\n
As detailed in a paper<\/a> published in the journal Geophysical Research Letters last month, a team led by Paris City University researcher Charlotte Gaugne Gouranton analyzed data collected by NASA\u2019s Gravity Recovery and Climate Experiment (GRACE) satellites between 2006 and 2008.<\/p>\n The two satellites were designed to monitor changes in the planet\u2019s underground water storage and sea levels, per NASA<\/a>. But the findings by Gouranton\u2019s team suggest they were able to probe far deeper than that.<\/p>\n By analyzing minute shifts in the Earth\u2019s gravitational field, they found evidence that material thousands of miles inside the Earth, near where the core meets the mantle, had mysteriously shifted.<\/p>\n Their findings could shed more light on the layers that make up the Earth and how they are interconnected, coauthor and University Gustave Eiffel in Paris geophysicist Isabelle Panet told Nature<\/a>. These connections could inform how the Earth maintains its shielding magnetic field, protecting us from space weather.<\/p>\n In their paper, the team proposes that perovskite, a type of mineral found at the bottom of Earth\u2019s mantle, may have changed the layer\u2019s structural configuration, causing rocks in the vicinity to become denser and increase in mass. These perturbations sent out ripples that could\u2019ve reached the boundary of the Earth\u2019s core.<\/p>\n These changes also could\u2019ve altered the way liquid rock flows inside the Earth\u2019s outer core, resulting in strange geomagnetic readings in GRACE data.<\/p>\n The blip, or \u201cgeomagnetic jerk,\u201d which peaked around 2007, showed up off the Atlantic coast of Africa, initially throwing Panet and her colleagues for a loop. Shifts in the Earth\u2019s groundwater, which the GRACE satellites helped scientists measure between 2002 and 2017, couldn\u2019t explain the strange signal.<\/p>\n \u201cSo at least partially, there has to be an origin within the solid Earth,\u201d Panet told Nature. \u201cIt has to come from very deep.\u201d<\/p>\n But to confirm their theory, the team will have to continue their investigation.<\/p>\n