Earth as a magnet: Understanding the magnetic field of our planet

Published: 2023-04-19 15:07:28 • Daniel Gårdefelt

Because our Earth has a magnetic field, our planet is often compared to a large magnet. This invisible force surrounds and protects our planet. It is an important part of many natural and human events. In this blog we will talk about the Earth's magnetic field, its history and properties and how it affects our daily life.

The Earth's magnetic field, also called the geomagnetic field, comes from the movement of molten iron and nickel in the planet's outer core. This process, called the geodynamo, creates electrical currents that give rise to a magnetic field that extends from the Earth's core to its outer atmosphere.

Properties of the Earth's magnetic field:
1. Polarity: Like a permanent magnet, the Earth's magnetic field has a north pole and a south pole. But unlike a permanent magnet, the Earth's magnetic poles do not line up with its geographic poles, and their positions can change over time because the geodynamo is so active.

2. Intensity: The strength of the Earth's magnetic field varies across the planet, with the force being strongest near the poles and weakest near the equator. This change in intensity is caused by things like the rotation of the Earth, the activity of the Sun, and the geology underneath.

How the Earth's magnetic field affects us:
The Earth's magnetic field has a major impact on both natural and human activities:

1. Compass Navigation: Earth's magnetic field is what makes compasses work. They point in the direction of the magnetic north pole by aligning with the magnetic field lines. Explorers and travelers have used compasses for decades to find their way. The compass can be traced back as far as 300 BC.

2. Aurora borealis and aurora australis: The fascinating northern and southern lights are created by the solar wind, which consists of charged particles emitted by the sun. These are captured by the Earth's magnetic field and are drawn to the poles at a very high speed. The northern lights occur when the particles collide with atoms and molecules in the Earth's upper atmosphere (ionosphere) and transform kinetic energy into visual light.

3. Protection against solar radiation: The Earth's magnetic field acts as a shield and deflects harmful charged particles from the sun, the so-called solar wind. Without this barrier, these particles could destroy Earth's atmosphere and make it impossible for humans to live here.

4. Effect on technology: The Earth's magnetic field can affect how technologies such as satellite communications, GPS systems and power grids work. Changes in the magnetic field can cause geomagnetic storms, which can disrupt these systems and cause problems for modern society.

The Earth's magnetic field, which is often compared to a giant magnet, is an important part of how our planet works and how people live on it. By learning about where this invisible force comes from, what it does and how it affects us, we can better understand how it affects our everyday lives, from navigation and natural events to how technology works.