The Earth’s core, which lies 5150 km below the surface, can be both hard and soft, according to a new study published in the scientific journal. Planetary physics and interiors – calls into question the scientific consensus that has existed since the fifties, according to which our center consists of a ball of solid iron covered with molten metal.
Like any research in the Earth’s core, it also has an observational character, as it needs to be done whether it is ‘hard’, ‘soft’ or both. However, pressure and temperature make travel impossible for any living thing or even any machine.
This didn’t stop Rhett Butler, a geophysicist at the University of Hawaii, from using the shockwaves caused by mantle earthquakes (the ‘second’ layer that makes up our planet, after the crust and before the core itself) to make a pervasive statement in the study he signed off on. :
« [Observações] illuminated by earthquakes in the crust and upper mantle, observed by seismic laboratories at the Earth’s surface, today offer the most direct way to observe our inner core and its processes,” said Butler.
Seismological studies – that is, analysis of earthquake shock waves – take into account changes in the velocity of these waves, and evaluate how they bounce off or break apart on the surface where they collide. Much of this is aimed more at average distances, but there are also applications of this science in other properties.
In this study, Butler and Seiji Tsuboi, a scientist from the Japan Maritime Land Science and Technology Agency, used data from seismographs that contrasted with earthquake locations. Using a seismographic supercomputer for simulations, they determined pairs of countries with and without earthquakes: Tonga-Algeria, Indonesia-Brazil, and three other analyzes considered Chile-China.
“Unlike Earth’s homogeneous iron alloy model, our study shows that there are regions alternating between hard, soft and liquid or thorough contents within the first 241.5 km of the core (from top to bottom),” said Butler. ‘This places new features in the history of Earth’s composition, temperature and evolution. “
In other words, think of the baby’s head: the top of the head is still relatively soft (usually called ‘softwood’). The difference is, over time the baby will tense his head, not the core of the earth.
This study gives considerable weight to understanding the working dynamics of our core, as it is responsible for the planet’s magnetic field. If your makeup changes, our understanding of this area may need to be revised as well.
“By knowing this state through seismology, we can lead to better and deeper predictive models of geomagnetic fields that protect life on our planet,” said Butler.
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