Earth’s Magnetic Field

You might say that planet Earth is a very large magnet. We have mentioned before Earth’s magnetic field that is generated by the iron core. The movement of that molten iron generates a magnetic field surrounding our planet. We can see the effect of that field every time we use a compass to find directions.

What you may not realize is that there is also a magnetic field generated by the ocean. Salt water is a good conductor of electricity. Moving electric currents generate magnetic fields. Hans Christian Ørsted discovered that by accident in 1820 when he noticed that placing a compass near a wire carrying an electric current caused deflection of the compass needle.

Salt dissolved in the oceans’ water creates ions, which are electrically charged particles. The movement of ocean tides causes those charged particles to move. Electric current is electrically charged particles in motion. Since electric current generates a magnetic field, the ocean tides generate magnetic fields. Because the movement of ocean currents and tides is complex, the magnetic fields generated by the oceans are more complex than the big magnetic field of the Earth. They are also 20,000 times weaker than Earth’s main magnetic field making them harder to measure.

Today’s satellite technology allows us to map the oceans’ magnetic field. The European Space Agency used three satellites to create a network called “Swarm.” They used the data from those satellites to create a 3-D digital map of this little-known magnetic field. The research shows how the field changes over time. Although the oceans create a relatively small part of Earth’s magnetic field, they play an important role. Mapping this field also give scientists a better picture of how the oceans flow all the way down to the seabeds. That information gives us a better understanding of Earth’s climate.

Combined with the magnetic field produced by the molten core and rocks in Earth’s crust, we are protected by a “cocoon” surrounding our planet. You might say, “Protected from what?” Our Sun frequently erupts in solar storms releasing charged particles that escape into space. Many of those particles travel to the Earth. We call it “solar wind.” Without a protective magnetic shield, those particles would reach Earth’s surface disrupting power grids and aircraft navigation. More basic than that, they would damage human cells causing cancers and other health problems.

We don’t think it’s by chance that we have the protection of Earth’s magnetic field. We see this as one more evidence of the provision of God to make possible life on this planet.
–Roland Earnst © 2018