Foundations of Scientific Knowledge

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Magnetic Reversals

Magnetic Sea-Floor Reversals

The Earth is a magnet, and it is for this reason that a compass works. A magnet in the compass is attracted to the magnetic pull of the Earth's north pole. Many scientists believe that at one point, today's north pole was magnetically the south pole, and that the roles have switched several times.

magnetic levels, from http://volcano.und.nodak.edu/vwdocs/vwlessons/plate_tectonics/part9.html

The sea floor is spreading apart, slowly but surely, as new material from the mantle rises and solidifies. One principle component of this material is iron. Iron is an element that has magnetic properties, and as part of this liquid rising to the core, iron is able to move. The iron lines itself up, pointing towards the north pole, and when the magma cools, it leaves a permenant record of the Earth's magnetic history (more info here). By using radiometric dating, we are able to tell how long ago it was when the poles were reversed.

magnetic patterns, from http://volcano.und.nodak.edu/vwdocs/vwlessons/plate_tectonics/part9.html

Nobody really knows what will happen when the poles reverse again. Will it be a gradual change? Or will it be a sudden change? What other enviornmental effects are associated with the change? Just a few decades ago, nobody believed that the continents were in motion. Although it may seem hard to believe that this amazing record has been preserved, using many of our other technologies, we are confident about this theory. The discovery of these patterns has helped support many other theories about the continents, and plate tectonics.

Fundamental Forces shaped the sea floor, and the magnetic reversals are a record of the Earth's electromagnetic influence on the sea floor, from millions of years ago.

Heat Transfer processes, like convection, are what drive the spreading of the sea-floor.

DNA is also similar to the sea-floor. Electromagnetic forces shaped the sea bed, and also shape complex molecules like DNA. Because of the shape and position of these charges, the bases on DNA can only be opposite from their corresponding base. This is an important characteristic of DNA, driven by the way these forces have interacted between atoms.