The Earth has a magnetic field and if we didn’t or if it failed, then life on this planet would not have started or would finish very quickly. It is that important. The reason for this is that it protects the surface of the Earth from the solar wind. These deadly particles would reach us and kill us if we did not have our magnetic field. The field is generated deep inside our planet (around 1,800 miles below), and it results from convection currents within the outer molten core of the Earth. The process involves superheated molten liquid producing an electric current and this, in turn, produces the magnetic field.
If we now extrapolate this, most of us have heard of the north magnetic pole. This is not the geographic North Pole. Compasses point to the north magnetic pole. But there is a problem and that is the magnetic pole is not stationary. It moves its position. Over the last 200 years, it has shifted from the Canadian Arctic towards Siberia in Russia. This movement is usually very slow but in recent decades it has speeded up. At the present time, it is estimated to be travelling at around 30 miles per year. At the same time, it is also weakening.
So, what effect does this have? One thing we should expect is that the Earth’s magnetic field could flip. What this means is that the north becomes south and vice-versa. Why do we suspect this to happen? It is because we have good evidence that it has flipped on a number of occasions in the past. The field came into existence about 4 billion years ago and during the last 2,600,000 years, we believe the field has flipped about 10 times. This works out that on average it flips about once every 260,000 years.
Great, so there isn’t anything to think about. Wrong, because the last flip occurred around 780,000 years ago. This indicates that we are well overdue for the next one. The weakening and faster movement may be indications that it is getting closer. However, we also know that the flip is usually spontaneous. Therefore, we do not know when it might next happen.
The big question is what effect will such a reversal have on us? Honestly, we do not know for sure. The change in polarity could affect many birds, animals and fish that use the magnetic field for navigation. But, what about humans? The possible danger to us comes first from the weakening of the magnetic field. If it should become too “thin” it will let in the radioactive particles such as protons and cosmic rays. We do have one thing in our favour and that is hominids of one sort or another have been around for about 2 million years. Therefore, the flips that have taken place did not kill everyone.
But there is another danger from the flip itself and that is the effect it will have on our technology. And by that, I mean almost everything we have come to rely on. It is thought that satellites may be affected and that would mean no GPS, communication problems, weather forecasting and a host of other tech services would suffer. We already have evidence of this as there is a part of the Atlantic Ocean known as the South Atlantic Anomaly where the magnetic field has become weak. This has resulted in some satellites suffering damaged circuits. Will all this come true in our lifetimes? We can only wait and see.
John Pullen 