Summary:

- The Earth's inner core, which is made of solid iron and nickel, may have a layered structure similar to an onion.
- Researchers used seismic data to analyze the properties of the inner core and found evidence of distinct layers within it, suggesting a more complex structure than previously thought.
- Understanding the inner core's structure is important for studying the Earth's overall composition and how it generates its magnetic field, which is crucial for life on the planet.