Is Earth's magnetic field the reason we exist?

Dr Maggie Lieu

We have all used one of those little compasses to find out which direction is North. But what makes those needles move is something much bigger and essential for making life on earth possible. What is it and why do we need it?

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China may have been the first culture to create a navigational magnetic compass as early as the 12th century. At that time compasses were used to inform prophecies, but ancient Chinese alchemists realised that a certain type of iron would point towards a magnetic north. Although their understanding was far from complete, they had an initial insight of what would become known as Earth’s magnetic field. 

This magnetic field extends several tens of thousands of kilometres into space and it interacts with several extraterrestrial objects making life possible on earth. For instance, Earth’s magnetic field protects us from dangerous solar winds. But the field doesn’t have the same strength everywhere and some researchers have found a weak area nearby the Bermuda Triangle, a region of the ocean known to swallow ships which has fascinated us for decades.

Join Dr Maggie Lieu as she reveals why Earth’s inner core is responsible for creating this invisible extraterrestrial wall protecting us and what do we know so far about other planets’ magnetic fields. 

What is Earth's magnetic field? How does it protect us?

Talk outline


50 minutes


Inner Earth

Dr Maggie Lieu

Dr Maggie Lieu is a a Research Fellow at Notthingham University interested in galaxy groups and clusters to help us better understand the cosmos.

Inner Earth Collection

From secret worlds to mystical doors, subterranean land appeared in ancient mythology, and legends in all kinds of flavours. But right under our feet lies an incredible force of nature capable of keeping us alive as well as posing existential threats

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