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The Magnetic Field


Swarm is ESA's latest Earth Explorer mission, launched on 22 November 2013, and consists of three satellites working together in orbit to study the Earth's magnetic field.

But what is the magnetic field, and why is it important that we understand more about it?

It is a field of energy generated by the Earth's core and extends outwards into space. In the case of our planet, this field of energy has two poles; North and South.

These poles have been used for centuries in navigation, helping people to determine direction in their travels, and scientists theorise that some animals (particularly birds) may be capable of naturally sensing the magnetic field and use it for their own navigation.

Beyond navigation, the magnetosphere - the region of the Earth's magnetic field that is at its furthest extent - acts as a barrier around the planet, and protects it from radiation that would otherwise be harmful to life on Earth. Without the magnetosphere our world would not be able to retain an atmosphere.

Because the field is natural, it gradually shifts and changes over time. Measurements conducted over the last century indicate that the field is weakening, but scientists do not yet have enough data to fully understand this process on a long-term scale.

Swarm will aid scientists by obtaining the most accurate measurements of the Earth's magnetic field yet and help us to understand this natural process.

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