What Causes Earth's Magnetic Field?
The most widely accepted theory regarding Earth's magnetic field is the dynamo theory. Simply, this theory states that Earth's magnetic field occurs due to movement called "convection currents." These are caused by Earth's rotation. Because they are liquid and good conductors, electricity can be produced.
In contrast the other planets, like Mars, Venus, and Mercury have no magnetic field or a very weak one.
Mars has no magnetic field due to its lack of convection currents and small size.
Venus does not have a magnetic field because it rotates too slowly to create convection currents.
Surprisingly, Mercury has a very weak magnetic field, even though it rotates very slowly.
What Does the Magnetic Field Do?
The magnetic field is a source of protection against radiation from space. As shown in the pictures below, the magnetic field forms a shield called the magnetosphere. This protects us from harmful particles from the sun. The magnetosphere allows the formation of an ozone layer, which is vital to life on Earth.
The magnetic field is also used in navigation of both humans and animals. Compasses will point in the direction of the magnetic field lines.
Watch an interesting video about the flipping of Earth's poles:
Some animals, such as birds, sharks, turtles, and more, have a "sixth sense" which allows them to sense Earth's magnetic field. This helps them navigate back to breeding grounds, feeding grounds, and migration destinations. Animals will detect differences in magnetic strength and flow, using that information to navigate with an "internal GPS."
Earth's magnetic field is always changing and remains essential to all life on Earth.
Written by: Mackenzie (@mprtchard)
Sources:
“Earth's Magnetic Lines.” Science On a Sphere, 5 Jan. 2021, https://sos.noaa.gov/catalog/datasets/earths-magnetic-lines/.
Hurley, Steve. “The Earth's Magnetic Field.” Explaining Science, 26 Apr. 2016, https://explainingscience.org/2016/04/24/the-earths-magnetic-field/.
Woodward, Aylin. “Sharks Are among a Group of Animals with a 6th Sense That Humans Don't Have - They Use Earth's Magnetic Field to Navigate.” Business Insider, Business Insider, 6 May 2021, https://www.businessinsider.com/sharks-animals-use-earth-magnetic-field-navigate-2021-5#:~:text=1%20Some%20shark%20species%20swim%20thousands%20of%20miles,seem%20to%20use%20the%20magnetic%20field%20to%20navigate.
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