The demagnetization of the magnet caused by heating is certain, and the experiment is very simple! Then the earth's internal temperature is even as high as 6000 degrees, and even high-temperature magnets have been demagnetized. Why does the earth still have a magnetic field that can protect itself? Where does this magnetic field come from? It is easy to confuse the two.
The inside of the earth is not a big magnet. Many of the earth's magnetic field diagrams show a super large NS pole magnet. In fact, the magnetic field inside the earth is a dynamic magnetic field, and this magnetic field is produced by a generator effect! There are many layers from the crust to the core. The rotation speed of the inner and outer layers caused by this iron-nickel fluid is different, and the geomagnetic generator effect comes from this. The outer layer is under the action of the initial magnetic flux. The induced current flow will give an excitation mechanism to the core, and under this action, the earth will have a normal magnetic field feedback and self-excitation mechanism, so the earth's magnetic field is continuous and never stops! But there is a saying that since the 17th century, the geomagnetic field has been weakening, and perhaps it will usher in a reversal, which will cause the earth to weaken the magnetic field for thousands of years in the future, or have a major impact on human production and life