Our Home: Earth, a Unique Life Sustaining Planet
The Earth's magnetic shield
Discover the invisible magnetic shield that surrounds the Earth.
In Curiosity, Grade 6, you learnt that a freely hanging magnet always settles pointing in a fixed direction. Why? Because the Earth itself behaves like a giant magnet.
In chapter 4 you saw that the region around a magnet where its effect can be felt is its magnetic field. The Earth has one, and it is believed to come from the movement of molten iron in Earth's core.
The Earth is constantly hit by tiny, high-energy particles from space. Some come from far across the universe: these are cosmic rays.
Others come from the Sun itself: this stream is the solar wind.
These particles can be harmful. They can damage the atmosphere and thin the ozone layer, letting in more harmful UV rays, and all of that would affect life on Earth.
Luckily, the Earth's magnetic field acts like a protective shield. It pushes many of these particles away from the Earth, keeping our atmosphere, and so life on our planet, safe.
Now put it all together. Four things make Earth a planet where life can begin and thrive:
| What | Why it matters |
|---|---|
| its position in the solar system | water can stay liquid |
| its size | it can hold an atmosphere |
| its atmosphere | oxygen to breathe, and the ozone shield |
| its magnetic field | it turns away harmful particles |
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