Researchers now believe that Earth's "solid" innermost core may be a little mushy.
The scientific community believed that Earth's inner circle was a ball of iron alloy and liquid, for more than 50 years. New research published in the journal Physics of the Earth, Planetary Interiors, Sept. 20, suggests that the firmness of the planet ball is a mixture of semisoft and hard metals.
Jessica Irving, a seismologist from the University of Bristol, England, said that "the more we look at it the more we realize that it's not just one boring blob of Iron." She was not part of the study. "We are discovering a whole new hidden universe."
Similar: 50 fascinating facts about Earth
Earth's inner core is still as mysterious today as it was in 1864 when Jules Verne published the fanciful "Journey to the Center of the Earth". Although scientists know that the Earth isn't as hollow as Verne predicted in the 1950s, its interior remains a mystery. The planet's immense heat and pressure make it impossible for humans or any other human-made probes to reach there. Irving stated that unless something terrible happens to Earth, there will never be a direct observation at Earth's core.
Geophysicists instead rely on seismic waves that are generated by earthquakes. Scientists can use these powerful vibrations to reconstruct the planet's inner workings. There are two types of these waves: undulating shear waves and straight-line compressional wave. As it travels through ground, each wave can be accelerated, slowed down or bounce off different mediums.
Image credit: Shutterstock.
Rhett Butler is a geophysicist from the Hawai’i Institute of Geophysics and Planetology. The new study began as a question of mismatched data. Butler was interested in how seismic waves from large earthquakes at five locations travel through Earth's center to the opposite end of the globe. However, something was wrong with the shear waves of earthquakes, which should have passed through solid metal balls, instead they were being deflected in some areas.
Butler was shocked by the numbers. He knew that the seismic wave math was correct. This could only mean one thing: Scientists had the structure incorrect. He said, "When you are in this business you have to match the data." Butler and his coauthor then reexamined their assumption that Earth's innermost core was completely solid. The waves they observed were not caused by a solid ball but pockets of fluid and semisolid iron at the core's surface.
Butler said that the range of iron types was quite remarkable. He said, "We have seen evidence that it is not soft everywhere. It's hard in some places." It has hard surfaces that are resistant to melted or mushy Iron. We are now seeing more detail in the inner core than we did before.
This research could revolutionize our understanding about Earth's magnetic field. According to Science Advances' 2019 research, while the planet's magnetic field is driven by the liquid outer core, the inner core modifies it. NASA research has shown that other planets have a liquid core, but no inner core or magnetic field. Butler and Irving believe that a better understanding of the inner core will allow scientists to understand the relationship between the planet's magnetic activity and its interior.
Original publication on Live Science
Researchers now believe that Earth's "solid" innermost core may be a little mushy.
The scientific community believed that Earth's inner circle was a ball of iron alloy and liquid, for more than 50 years. New research published in the journal Physics of the Earth, Planetary Interiors, Sept. 20, suggests that the firmness of the planet ball is a mixture of semisoft and hard metals.
Jessica Irving, a seismologist from the University of Bristol, England, said that "the more we look at it the more we realize that it's not just one boring blob of Iron." She was not part of the study. "We are discovering a whole new hidden universe."
Similar: 50 fascinating facts about Earth
Earth's inner core is still as mysterious today as it was in 1864 when Jules Verne published the fanciful "Journey to the Center of the Earth". Although scientists know that the Earth isn't as hollow as Verne predicted in the 1950s, its interior remains a mystery. The planet's immense heat and pressure make it impossible for humans or any other human-made probes to reach there. Irving stated that unless something terrible happens to Earth, there will never be a direct observation at Earth's core.
Geophysicists instead rely on seismic waves that are generated by earthquakes. Scientists can use these powerful vibrations to reconstruct the planet's inner workings. There are two types of these waves: undulating shear waves and straight-line compressional wave. As it travels through ground, each wave can be accelerated, slowed down, or bounce off of various mediums.
Image credit: Shutterstock.
Rhett Butler is a geophysicist from the Hawai’i Institute of Geophysics and Planetology. The new study began as a question of mismatched data. Butler was interested in how seismic waves from large earthquakes at five locations travel through Earth's center to the opposite end of the globe. However, something was wrong with the shear waves of earthquakes, which should have passed through solid metal balls, instead they were being deflected in some areas.
Butler was shocked by the numbers. He knew that the seismic wave math was correct. This could only mean one thing: Scientists had the structure incorrect. He said, "When you are in this business you have to match the data." Butler and his coauthor then reexamined their assumption that Earth's innermost core was completely solid. The waves they observed were not caused by a solid ball but pockets of fluid and semisolid iron at the core's surface.
Butler said that the range of iron types was quite remarkable. He said, "We have seen evidence that it is not soft everywhere. It's hard in some places." It has hard surfaces that are resistant to melted or mushy Iron. We are now seeing more detail in the inner core than we did before.
This research could revolutionize our understanding about Earth's magnetic field. According to Science Advances' 2019 research, while the planet's magnetic field is driven by the liquid outer core, the inner core modifies it. NASA research has shown that other planets have a liquid core, but no inner core or magnetic field. Butler and Irving believe that a better understanding of the inner core will allow scientists to understand the relationship between the planet's magnetic activity and its interior.
Original publication on Live Science
