Earth is truly a fascinating ball of huge mass with some astonishing scientific processes governing the fine balance of life in it. One of these processes is a giant magnetic field surrounding it, going from north to south pole just like on any other magnet you have ever seen. The magnetic field helps to block powerful solar winds. If not, those charged particles would obliterate life and strip away the ozone layer that protects us from harmful ultraviolet radiation.
Although we can’t say for sure, the scientists believe that the magnetic field originates from a mechanism called the dynamo, which is the combination of a metallic liquid zooming throughout the Earth’s outer core and our planet’s rotation. This generates an electric field which, in turn, creates the ozone-saving magnetic field. As a demonstration of this mind-boggling phenomenon, scientists at L’Institut des sciences de la Terre, France have come up with a mesmerizing animation of the Earth’s outer core sliced in half and showing a computer model of the changes in temperature patches deep inside the core of our planet.
These simulations depict the metal flows created by the molten iron-nickel mixture swirling at different temperatures. The pictures also demonstrate moving vortices near the poles and the consequential magnetic fields generated by this motion which is generally non-uniform. The team has submitted their work for publication in the Geophysical Journal International.
This animation is an attempt to create a realistic model of the dynamo and is based on numerical approximations and supercomputer calculations as stated by the French National Center for Scientific Research stated in a press release.
It’s hard to work out how fast the core performs heat convection because no one is entirely sure of the viscosity of the nickel/iron (+sulphur, silicon, and oxygen) alloy that makes up the core. This is because we’re not exactly sure of its precise chemical composition and also because different concentrations of sulfur, silicon, and oxygen dramatically affect the viscosity of alloy.
Some calculations show that it is about as runny as water while some express it to be rigid. Certainly, the core moves by kilometers per year (this paper expresses it at 10-30km per year) which is many thousands of times faster than the overlying mantle. To put that into perspective, the outer core is 2300km thick, so you are looking at 75-230 years to travel through the entire thickness of the layer.
Here’s a really weird fact, the inner core (which is very nearly as massive as the moon) rotates faster than the earth as a whole by 0.3-0.5 degrees per year!