Magnetic Material & Terrestrial Magnetism

Earth’s magnetic field (also known as the geomagnetic field) is the magnetic field that extends from the Earth’s inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun. Its magnitude at the Earth’s surface ranges from 25 to 65 µT. It is approximately the field of a magnetic dipole tilted at an angle of 11 degrees with respect to the rotational axis—as if there were a bar magnet placed at that angle at the center of the Earth. However, unlike the field of a bar magnet, Earth’s field changes over time because it is generated by the motion of molten iron alloys in the Earth’s outer core (the geodynamo).

Problems with magnetic materials that it had not been possible to replace on Galilee, led to the building of the Carnegie in 1909, which was constructed with virtually no magnetic materials. Galilee was later rigged as a schooner, had a diesel engine fitted and was used in the fishing industry before being beached in 1933, ending her active career. The stern and part of the bow are preserved in two different places in California.