The Earth’s inner core has long been thought to be a hard ball of compressed iron alloy surrounded by a liquid outer core. However, recent research published in Physics of the Earth and Planetary Interiors shows that the state of the inner core can range from solid to semi-soft and even liquid. This opens up new possibilities for studying the hidden world of the Earth’s core.
According to Jessica Irving, a seismologist at the University of Bristol in England, “The more we study [the core], the more we realize that it is not just a boring piece of iron. We find a whole new hidden world.
Studying the Earth’s core
The study of our planet’s core is conducted using seismic waves caused by earthquakes. Scientists measure these vibrations and reconstruct a picture of the Earth’s interior, using a method similar to a human computer tomography.
Waves come in two basic types: longitudinal and transverse waves. Each wave can accelerate, decelerate, or be reflected from different environments as it moves. This allows scientists to obtain data about the state of the Earth’s core.
Rhett Butler, a geophysicist at the Hawaii Institute of Geophysics and Planetary Science, noticed a mismatch in data when studying the Earth’s core. Seismic waves generated by earthquakes in different places on the planet pass through the core and are reflected on the opposite side of the globe. However, the transverse waves, which should pass through a solid metal ball, were deflected in certain areas.
Butler notes that the range of iron consistencies is particularly striking. “We have seen evidence that the core is not only not hard everywhere, but can be very soft in some places,” the scientist says.
Impact on Earth’s magnetic field
Studies of the Earth’s core may have important implications for understanding our planet’s magnetic field. According to data published in Science Advances in 2019, the liquid outer core controls our planet’s magnetic field, while the inner core helps change it.
In contrast, NASA data on other planets, such as Mars, show that they have a liquid center but lack both an inner core and a magnetic field. Butler and Irving believe that a better understanding of the structure of Earth’s inner core will help understand the relationship between the planet’s interior and its magnetic activity.
The study of the hidden world of the Earth’s core remains one of the most interesting and mysterious tasks for science. Despite advances in research, many questions remain that require answers. However, new data and discoveries allow scientists to get an increasingly accurate picture of the inner workings of our planet.