Huge Gravity Anomaly Discovered!

Quick Overview

Researchers using GRACE satellite data detected a rapid, transient gravity anomaly originating near the African coast between 2006 and 2008, which they suggest reflects a mineral phase transition of bridgmanite deep within the Earth's mantle, causing mass redistribution and a corresponding change in the magnetic field that was not fully explained by surface water variations.

Key Points: A rapid, transient gravitational anomaly, 7000 km long, occurred off the coast of Africa between 2006 and 2008. This anomaly, observed by the GRACE satellites, is too fast and deep to be fully explained by surface water mass redistribution. The data suggests the anomaly reflects a phase transition of bridgmanite, a major mineral in the lower mantle (around 3000 km deep), from the pPv phase to the Pv phase. This phase transition caused a localized mass excess (upward movement) and mass default (downward movement) near the core-mantle boundary (CMB), resulting in a measurable gravity change. The change in gravitational pull coincided with a similar, rapid change observed in the Earth's magnetic field, suggesting a link between deep mantle processes and the magnetic field. The GRACE mission (2002–2017) and its successor GRACE-FO (2018–present) provide the foundational data for measuring these month-to-month gravity changes. The video promotes the Vsauce Curiosity Box subscription service, featuring items like a reversible scarf and an orrery calendar.

Context: The video, presented by Sabine Hossenfelder, discusses new geophysical findings regarding transient gravity anomalies detected by the GRACE satellite mission, which measures month-to-month changes in Earth's gravity field. The focus is on an unexplained anomaly detected off the coast of Africa between 2006 and 2008, which scientists now hypothesize is caused by a phase transition of bridgmanite, a high-pressure mineral in the Earth's deep mantle, potentially linking deep Earth dynamics to surface gravity and magnetic field variations.