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For example, the north pole has been “wandering” for around the last hundred years, heading slowly towards Siberia. Scientists measuring the Earth’s magnetic field have noticed that the location of the poles are not completely fixed. The Earth’s magnetic field has a structure similar to a simple magnet, with a north pole and a south pole. Dr Franco uses complex numerical models to better understand Earth’s magnetic field structure, the dynamo that drives geomagnetism and palaeosecular variation. As the planet rotates, these convection currents are forced into columns along which move electrical currents, generating a huge magnetic field that extends out into the space around the Earth. Earth’s inner core is extremely hot, over 5000 ☌, and this heat drives convection currents in the Earth’s fluid, metallic outer core. Deep inside the Earth, fluid with the capacity to conduct electrical currents is constantly moving. This is when a flowing electrical current creates a magnetic field.
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More about the changes in Earth’s palaeomagnetic field and why they might occur.Ī magnetic field can also be generated by a dynamo. However, it is something much more complex than a metal magnet generating Earth’s magnetic field.Ĭomplex numerical models help geologists understand Earth’s magnetic field is well known to have a north pole and a south pole (we call this type of magnetic field an axial dipole), and when you stand on the Earth’s surface with a compass, the needle will align itself to the field pointing towards the north pole. Magnets have two poles, generally termed a north and south pole, and the magnetic field flows from the north pole, around the outside of the magnet to the south pole.
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A magnet creates an invisible magnetic field, which describes the area of influence around a magnet. A magnetic field can be created by a magnet, a piece of permanently magnetised metal that can attract or repel other materials. To understand why Earth’s magnetic field changes through time, we first must understand how it is formed. Earth’s rocks hold clues about its magnetic field in the past (the palaeomagnetic record), which geophysicists like Dr Daniel Franco at the National Observatory of Brazil, can bring together to understand how the palaeomagnetic field might have behaved. Understanding how the magnetic field has changed through time will hopefully give us clues as to how it might fluctuate in the future. Dr Franco aims to better understand the structure of Earth’s magnetic field and what might cause these changes over geological timescales. Increases in the solar wind (geomagnetic storms) can disrupt power grids, communications, satellites and navigation systems, and without a stable magnetic field to protect Earth we would be incredibly vulnerable to solar storm events. Mobile phones depend upon it to correctly identify their location. The stability of today’s magnetic field is not only important for protecting life on Earth, it is vital for our technology. Scientists can also measure its intensity at points around the Earth’s surface, as well as its orientation, and satellites play a vital role in its continued monitoring. Humans have been using the Earth’s magnetic field to navigate for hundreds of years using compasses, and this remains the easiest way for us to see Earth’s magnetic field in action. But how can we understand something we cannot even see? This is what causes the aurora to dance in the skies around the North and South Pole, and protects life on Earth from the intense stream of solar particles racing across the solar system from our Sun. Dr Daniel Franco and his team at the National Observatory of Brazil use complex numerical models to better understand the structure of Earth’s magnetic field and what might cause these changes over geological timescales.Įarth is surrounded by an invisible yet powerful shield: its magnetic field. Earth’s rocks provide a record of geomagnetic reversals and variations through time in the geomagnetic field. However, the Earth’s magnetic field has not always been quite the same. Complex convection currents in the Earth’s core create a vast magnetic field around the Earth, protecting us from the charged solar particles that emanate from the Sun.