We all know that our Earth has a magnetic field. That’s why compasses work and we know that the field also helps to protect us from radiation coming from outer space. However only a few people are aware of the fact that the Earth’s north and south magnetic poles have flipped many times in the past, and appear to be getting ready to flip again.
By the way, did you know that since a compass’s north pole points north and with magnets opposites attract, then there must be a south magnetic pole up at the actual North Pole! I’ll say that again ’cause I know how strange it sounds. Up at the Earth’s actual North Pole there is a south magnetic pole, that’s why a compass points north. The reverse is also true, at the actual South Pole there is a north magnetic pole.
By measuring the slight magnetic field frozen into igneous rocks as they solidify geologists have been able to determine that the magnetic poles switch positions every couple of hundred thousand years. (Note: The real North and South poles, the axis around which the Earth rotates, are not changing, it’s only the magnetic poles that flip.) The last time the magnetic poles flipped was 720,000 years ago so we are overdue! The picture below is based on current theories on how such a reversal will take place.
Also, we know that the Earth’s field is weakening right now. Over the past 150 years, as long as we’ve been measuring it, the Earth’s field has weakened dramatically. And then there’s the South Atlantic Anomaly, a vast region stretching from South Africa to South America where the magnetic field has virtually disappeared and a new magnetic pole looks like it’s starting to pop out! Check out the actual measurements of the Earth’s magnetic field strength in the picture below.
Now a new study of the South Atlantic Anomaly has succeeded in measuring the decline in the field strength over the past 2000 years. Geophysicist John A. Tarduno of the University of Rochester along with Michael K. Watkeys of the University of KwaZulu-Natal have been able to use the archeological remains of iron age huts in the Limpopo River Valley as archeomagnetic samples.
You see, the iron age people living along the Limpopo River had the ritual of burning down their huts during times of drought as a way of ‘cleansing’ them. The heat of the fires caused the magnetic particles in the clay to lose whatever original magnetic orientation they had and then, as the clay cooled the magnetic particles would align themselves to the Earth’s magnetic field at that place and time! This left a record of the changes to the Earth’s magnetic field in South Africa that Professor Tarduno and his colleagues have been able to read. What they have found is that the magnetic field in the past has had periods of rapid decline followed by a slow return. Further evidence that the Earth’s magnetic field is entering a period of flux and perhaps a total collapse leading to a flip. If you’d like to read more about Professor Tarduno’s work click on the link below.
So how does all of this effect me, I hear you ask? Won’t I be able to use a compass the next time I go camping? Well there’s a bit more to it than that. The Earth’s magnetic field shields us from the solar wind and the radiation associated with it. As the Earth’s magnetic field weakens we can expect cancer rates, especially skin cancer to greatly increase. The solar wind can also effect both the power grid and the lifespan of satellites in orbit above the Earth. The flipping of the Earth’s magnetic field may take a couple of hundred years to complete and during that time we shall have to learn to live without its protection.