The Earth's magnetic field is attributed to a dynamo effect of circulating electric current, but it is not constant in direction. Rock specimens of different age in similar locations have different directions of permanent magnetization. Evidence for 171 magnetic field reversals during the past 71 million years has been reported.
1. The earth is a giant electromagnet. The power for this electromagnet comes from the solar winds that are composed of protons and neutrons that collect at either pole and the flowing electrons power the earth’s electromagnet field.
Why do I think that? There has to be evidence in nature to support my theory. Lets look at an actual magnetic field of a bar magnet. This is done by placing a bar magnetic under a piece of paper that has iron filings on it. It looks like this; (we have all done this as children)
Each one of those lines of magnetic field is in opposition to the next, each repelling the next in both directions. You cannot help but notice there is space between the magnetic field lines.
Now think in solar and galactic terms and the space between the magnetic field lines are immense. If the earth was an electromagnet as I theorize every time it crossed a magnetic field line its polarity would reverse. Just like this;
There is a ton of math I have to do to prove this but my pictorial example shows how earths orbit remains steady, but as the suns angle changes over millions of years the earth would shift through the magnetic field lines.
The math involves the sun’s orbital speed around the galaxy, the speed the sun oscillates up and down in its orbit of the galaxy, the distance covered in latitude, and some other items I will have to think about. But I will bet you the answer is that the earth crosses one of sun’s magnetic field lines every 415,205 years. When it crosses the line the magnetic field reverses just like any good electromagnet that is in repulsion mode.
The math will also reveal the distance between the sun’s lines of magnetism which will lead to other answers.