For more than half a century, the scientific community has believed that the Earth’s inner core is a solid ball of compressed iron alloy surrounded by a liquid outer core. But new research was published on September 20 in the journal Earth and inner planet physicsAnd It indicates that the hardness of the planetary sphere varies from a solid to a semi-soft to a liquid metal.
“The more we look at it, the more we realize that it is not a boring drop of iron,” he said to WordsSideKick.com Jessica Irving, a seismologist at the University of Bristol in England, who was not involved in the study. “We are finding a whole new hidden world.”
In a way, the Earth’s inner core is still as mysterious as it was when Jules Verne published his wonderful Journey to the Center of the Earth in 1864. Although scientists have known since the 1950s that our planet is not as hollow as Verne predicted, the planet’s interior remains unexplored.; The enormous heat and pressure are simply too great for any human or man-made probe to travel there. “Unless something terrible happens to our planet, we will never have direct observation of the Earth’s core.” Irving said.
Instead, geophysicists rely on seismic waves generated by earthquakes. By measuring these massive vibrations, scientists can reconstruct a picture of the inner workings of the planet in a way that is Similar to a person’s CT scan, Irving said. These waves come in two main types: straight line pressure waves and wavy shear waves. Each wave can accelerate, slow down, or bounce different media as it travels through the Earth.
For Rhett Butler, a geophysicist at the Hawaii Institute of Geophysics and Planetary Science, the new study began on the basis of a number mismatch. Butler was observing how seismic waves from large earthquakes in five different locations travel through the Earth’s core to the opposite side of the globe. But something was wrong: Instead, the seismic shear waves, which should have passed through a solid ball of metal, are deflected in certain areas.
The numbers surprised Butler. He knew the mathematics of seismic waves was correct, which could only mean one thing: the scientists had the wrong structure.
“When you’re in this business, you have to match the data,” She said.
Therefore, Butler and his partner re-evaluated their basic assumption that the Earth’s inner core is completely solid. They find that the waves they observed operate if, Rather than being a solid ball, the core had pockets of liquid and “soft” semi-solid iron near its surface.
The iron’s consistency was particularly surprising, according to Butler. “We’ve seen the evidence that not only is it not smooth everywhere; it’s really hard in some places”, She said. “It has hard surfaces against cast iron or soft iron. So we see a lot of details inside the inner core that we haven’t seen before.”
This research could revolutionize our understanding of the Earth’s magnetic field. While the swirling fluid outer core drives our planet’s magnetic field, the inner core helps modulate the field, according to research published in 2019 in the journal Science Advances.
Other planets, such as Mars, have a liquid center but lack both an inner core and a magnetic field, according to NASA research. Therefore, Butler and Irving believed, uA deeper understanding of the inner core will help scientists understand the relationship between the planet’s interior and its magnetic activity.