When do scientists predict earths magnetic field will fade away?
Since early in the 20th century, it became apparent to geologists that the earth has undergone periodic magnetic pole reversals. They found these apparent reversals by examining layer upon layer of volcanic basalt, particularly in the Hawaiian islands. These reversals happened at an average frequency of about four each million years. They also seem to happen fairly rapidly. Recently it has become apparent that the magnetic field is declining. For about 300 years, the strength of the magnetic field has been known in relative terms. The early data was from old ship’s logs which measured both inclination and declination. Inclination at various latitudes, or the vertical angle of the field, gives us an indication of field strength. Since late 18th century, the magnetic field could be measured directly from laboratory experiments. It is believed by some scientists that the earth may have a pole reversal in perhaps a few hundred years. At least one computer program that models the known dyna
