00:07Earth's magnetic field protects us from harmful particles in the solar wind.
00:11It extends deep into space, but is generated deep within our planet.
00:19By using satellites to measure fluctuations in the magnetic field,
00:23scientists are gaining new insights into Earth's interior.
00:29Unlike fixed observatories on Earth's surface,
00:31satellites can measure the magnetic field both globally and in great detail.
00:36The magnetic field is generated by swirling liquid iron in the outer core,
00:41which acts like a giant dynamo.
00:44Measurements from ESA's swarm satellites have revealed a new type of wave motion
00:48mapped at the core-mantle boundary.
00:55The wave oscillates around every seven years, propagating westward at 1,500 kilometers a year.
01:07Combining these observations with a computer model of the geodynamo
01:11explains the source of magnetic field variations initially detected on the ground.
01:37Future measurements from space could help us understand more about the electrical properties of the lower mantle,
01:42and about the magnetic field from deep in the fluid core.
01:48This research has important implications for our understanding of the geodynamo,
01:52the structure of the outer core, and the thermal history of Earth.
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