The innermost core of the Earth is likely a ball of iron with a radius of approximately 650 km, an Australian research has found.
In a new study, a team from the Australian National University (ANU) analyzed how seismic waves caused by earthquakes penetrate and pass through the Earth’s core, shedding new light on the deepest parts of the planet.
They observed for the first time the waves reverberating along the Earth’s diameter five times — a finding the seismologists said confirms there are five distinct layers of the planet’s structure rather than four.
“The existence of an internal metallic ball within the inner core, the innermost inner core, was hypothesized about 20 years ago. We now provide another line of evidence to prove the hypothesis,” Thanh-Son Pham, co-author of the report from the ANU Research School of Earth Sciences, said in a media release.
The researchers analyzed seismic waves that travel directly through the Earth’s center to the opposite side of the globe to where the earthquake was triggered before traveling back to the source.
“By developing a technique to boost the signals recorded by densely populated seismograph networks, we observed, for the first time, seismic waves that bounce back-and-forth up to five times along the Earth’s diameter. Previous studies have documented only a single antipodal bounce,” Pham said.
“The findings are exciting because they provide a new way to probe the Earth’s inner core and its centermost region.”
Co-author, Hrvoje Tkalcic, said studying the deep interior of the Earth could tell us more about the planet’s past and help solve the mystery of its formation. ■