Understanding the outer core was important, he said, as it was critical to the survival of life at the surface. It was responsible for the magnetic field, which protected Earth from the constant bombardment of charged particles from the sun.
Currents moving within the molten iron and nickel acted like a “giant dynamo” that generated and sustained the Earth’s magnetic field.
Tkalčić said scientists did not yet know why the Earth had this active dynamo when many other planets did not: “It’s fair to say that we understand the surfaces of other planets in more detail than our own planet’s interior.”
Earth’s interior – a solid centre containing the inner core, encapsulated by a liquid outer core and then the mantle – was just as immense, he said.
Overall the core was slightly larger than Mars. “We can think of it as a planet within our own planet,” Tkalčić said.
He added: “We don’t know the exact thickness of the doughnut, but we inferred that it reaches a few hundred kilometres beneath the core-mantle boundary.” The structure’s buoyancy suggested the presence of lighter chemical elements such as silicon, sulphur, oxygen, hydrogen or carbon.
— Read on www.theguardian.com/environment/article/2024/aug/31/vast-doughnut-discovered-in-molten-metal-of-earth-core
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