Scientists find signs of a hidden structure inside the core of the Planet Earth

The breakthrough discovery has been named as “FIFTH LAYER”

• In a breakthrough discovery, scientists have detected signs of a hidden structure inside the core of the Earth
• The discovery having the potential to change the long-standing narrative of what’s in the centre of the planet
• Terming it the ‘fifth layer’ apart from the previously known four layers – the crust, the mantle, the outer core and the inner core

Background of Discovery of the FIFTH LAYER

• The researchers used travel time data for seismic waves travelling inside the Earth and captured by the International Seismological Centre
• Following this, they used their new algorithm to search through the data to discover evidence of changes in the structure of Earth’s inner core
• Despite it being ‘particularly difficult’ to detect the minute changes, the researchers were able to demonstrate that two separate cooling events in the history of the planet
• It also implies that in the earliest years of Earth’s evolution, at least 4.56 billion years ago, the planet went through a dramatic and previously unknown event at some point
• Details of this particular “big event are still a bit of mystery” but the researchers were able to add another “piece of puzzle” when it comes to the knowledge about Earth’s core
• Even though the observations were indirect, geologists were able to determine that the inner core of Earth reaches temperatures of more than 5,000 degrees Celcius and is relatively smaller in area, that is, it makes up only 1% of the total volume of Earth

The Fifth Layer – The Complex core

• At the very center of the inner core, something seems to be different, scientists noticed in the early 2000s. At this depth, the anisotropy seemed not to match that of the rest of the inner core
• The scientists brought together a dataset of about 100,000 earthquake waves that passed through this level of the core and applied an algorithm that searches for the best physical explanation of what’s going on to explain the data
• What they found was that in the inner-inner core, starting about 400 miles (650 km) from the center of Earth, the anisotropy in the slow direction isn’t quite parallel with the equator anymore, but 54 degrees off
• This isn’t just noise in the data, this is really something that’s there. But it’s not easy to say what that something is in there
• The researchers are now working with mineral physicists and geodynamicists to try to come up with models of the inner-inner core that would explain this change. As the planet cools, the inner core is cooling and expanding
• Imaging the core is complex, in part because the deep earthquakes that scientists use for imaging don’t occur evenly across the globe. This spotty dataset leads to blind spots
• Seismologists and geophysicists are now working on ways to tease out subtle types of earthquake waves called exotic phases that have passed through the inner core
• These phases are usually too subtle to make out from a single earthquake, but they can be detected in large datasets of thousands of earthquakes

Layers of Earth so far under consideration

• EARTH’S CRUST is like the shell of a hard-boiled egg. It is extremely thin, cold and brittle compared to what lies below it. The crust is made of relatively light elements, especially silica, aluminum and oxygen. It’s also highly variable in its thickness
• The MANTLE is at close to 3,000 kilometers (1,865 miles) thick, this is Earth’s thickest layer. It starts a mere 30 kilometers (18.6 miles) beneath the surface. Made mostly of iron, magnesium and silicon, it is dense, hot and semi-solid (think caramel candy). Like the layer below it, this one also circulates. It just does so far more slowly
• OUTER CORE is also made from iron and nickel, just in liquid form. It sits some 5,180 to 2,880 kilometers (3,220 to 1,790 miles) below the surface. Heated largely by the radioactive decay of the elements uranium and thorium, this liquid churns in huge, turbulent currents. That motion generates electrical currents
• INNER CORE is a solid metal ball that has a radius of 1,220 kilometers (758 miles), or about three-quarters that of the moon. It’s located some 6,400 to 5,180 kilometers (4,000 to 3,220 miles) beneath Earth’s surface. Extremely dense, it’s made mostly of iron and nickel. The inner core spins a bit faster than the rest of the planet. It’s also intensely hot: Temperatures sizzle at 5,400° Celsius (9,800° Fahrenheit). That’s almost as hot as the surface of the sun.

Science and Technology