Came across a (https://www.youtube.com/watch?v=g6thUIR3_rI) which describes Earth’s magnetic field having switched hundreds if not thousands of times during Earth’s 4.5 billion years.
So, how do we know thats a fact? What are scientists looking at that helped them determine this?
In: 2148
This was actually discovered in large part by the US Navy, as they looked for technology to find submarines.
As they looked at patterns of magnetism across the Atlantic seafloor, they discovered patterns in the seafloor that showed magnetic reversals. These rocks were later age-dated to find the time line of the reversals. This also helped prove plate tectonic theory.
https://www.sciencenews.org/article/fluxgate-magnetometer-submarine-plate-tectonics
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