Earth's "solid" inner core might actually be a bit mushy, researchers now find. For over half a century, the scientific community thought that Earth's inner core was a solid ball of compressed iron alloy surrounded by a liquid outer core. But new research, published Sept. 20 in the journal Physics of the Earth and Planetary Interiors, suggests that the firmness of the planetary ball ranges from hard to semisoft to liquid metal.
"The more that we look at it, the more we realize it's not one boring blob of iron," Jessica Irving, a seismologist at the University of Bristol in England, who was not involved in the study, told Live Science. "We're finding a whole new hidden world."
In some ways, Earth's inner core remains as mysterious as it was when Jules Verne published his fanciful "Journey to the Center of the Earth" in 1864. Though scientists have known since the 1950s that our planet isn't hollow as Verne predicted, the planet's interior is still unexplored; the immense heat and pressure are simply too great for any human or human-made probe to travel there. "Unless something awful happens to our planet, we will never have a direct observation of 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 planet's inner workings in a way that's "akin to a CT scan of a person," Irving said. These waves come in two main flavors: straight-line compressional waves and undulating shear waves. Each wave can speed up, slow down or bounce off of different mediums as it travels through the ground. READ MORE...
