In this month's lesson we will be learning about Earth's magnetic field, the Aurora Borealis/Aurora Australis, what causes them and why our magnetic field is so important to life on Earth.
Pictured Above: The Aurora Borealis lighting up the night sky over Tacoma, Washington. Dozens of stars can be seen behind the aurora. The rays of light appear to make an eye or circle shape above the viewer. The brilliant greens and purples showcase Earth's magnetic field working hard to protect all inhabitants on the face of the planet.
Earth’s magnetic field, or geomagnetic field, is the invisible forcefield that protects our planet from harmful particles emitted by our very own sun, known as solar wind. The geomagnetic field is generated deep within the iron core of the Earth. For a planet to be able to generate it’s own geomagnetic field, it must have all criteria for the Geodynamo Process. These criteria are: the planet rotates fast enough, has a fluid interior that conducts electricity, and the core has a source of energy to fuel convection currents. Mars is an example of a planet that does not meet these criteria and thus does not produce a magnetic field. But Saturn, Jupiter, Uranus and Neptune have magnetic fields that are much stronger than Earth’s!
Our magnetosphere produces one of Earth’s most spectacular light shows: the Aurora Borealis in the Northern Hemisphere and the Aurora Australis in the Southern Hemisphere. The auroras are produced near Earth’s magnetic poles where charged particles from solar wind are funneled down into our atmosphere and collide with the elements such as oxygen and nitrogen. The auroras are the magnetosphere hard at work protecting the atmosphere from eroding away. However, the geomagnetic field isn’t always perfect. When large amounts of solar radiation are emitted at once, known as a Coronal Mass Ejection (CME), it can cause our geomagnetic field to falter and lead to issues with radio communications and power black outs. Next time you see the auroras, be sure to thank our geomagnetic field for keeping us safe!
Sources:
Dobrijevic, Daisy. “Earth’s Magnetic Field: Explained.” Space.com, 6 July 2022, www.space.com/earths-magnetic-field-explained.
USGS. “How Does the Earth’s Core Generate a Magnetic Field?” Usgs.gov, 3 Nov. 2022, www.usgs.gov/faqs/how-does-earths-core-generate-a-magnetic-field.
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