CONTEXT: In a new study, scientists reveal how Earth’s inner core is growing faster on one side than the other, which could help explain how old the inner core is, and the intriguing history of Earth’s magnetic field
Analysis:
- The eastern and western halves of the inner core showed different seismic wave speed variations. The eastern part of the inner core is beneath Asia, the Indian Ocean and the western Pacific Ocean, and the west lies under the Americas, the Atlantic Ocean and the eastern Pacific.
- The new study found that the eastern inner core located beneath Indonesia’s Banda Sea is growing faster than the western side beneath Brazil.
- You can think of this uneven growth as like trying to make ice cream in a freezer that is only working on one side: ice crystals form only on the side of the ice cream where the cooling is effective. In the Earth, the uneven growth is caused by the rest of the planet sucking heat more quickly from some parts of the inner core than others.
- But unlike the ice cream, the solid inner core is subject to gravitational forces which distribute the new growth evenly through a process of creeping interior flow, which maintains the inner core’s spherical shape. This means that Earth is in no danger of tipping, though this uneven growth does get recorded in the seismic wave speeds in our planet’s inner core.
Reference: Earth’s inner core
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