Researchers are still discovering more about the center of the Earth. A team from the Australian National University (ANU) has evidence found of a new layer to the planet sitting inside the inner core. This “innermost inner core” is a ball of iron-nickel alloy which, as Professor Hrvoje Tkalčić explains, is a “fossilized record” of Earth’s ancient history. Until now, science had only recognized four layers (crust, mantle, outer core, and inner core).
Scientists found the ‘hidden’ core by studying seismic waves that traveled back and forth across the entire diameter of the Earth up to five times; previous studies only looked at individual rebounds. Waves from the earthquake probed locations near the center at angles that suggested a different crystalline structure within the innermost layer. Effectively, the alloy is skewing the travel times of the waves as they pass.
The findings open up new ways to investigate the inner core, according to lead author Thanh-Son Phạm. ANU also believes that the innermost inner core suggests a major event in Earth’s past that had a “significant” impact on the planet’s heart. as researchers explain to the washington post, could also help explain the formation of the Earth’s magnetic field. The field plays an important role in sustaining life, protecting the earth from harmful radiation and preventing water from drifting into space.
Those ideas can help with studies of other worlds. Mars is thought to be an arid planet because it lost its magnetic field about four billion years ago, leaving no protection from solar winds and dust storms that swept away the atmosphere and oceans. Meanwhile, exoplanet hunters could use the knowledge to search for habitable worlds. The presence of a core Earth-like structure is not guaranteed to indicate survivability, but may play a role in narrowing down candidate planets.
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