因为地球是个大磁体,所以我们才能用指南针辨别方向．地球磁场的南北极与地理上所说的南北极是有区别的．地球磁场的南极靠近地球的北极,而地球磁场的北极靠近地球的南极,地磁极和地球的地理南北极并不重合．地球的磁场十分类似于假设在地球内部深处有一根巨型的棒形磁铁所产生的那种磁场． Because the earth is a big magnet, we can use the compass to tell the direction. The north and south poles of the Earth’s magnetic field are geographically different from the north and south poles. The south pole of the earth’s magnetic field is close to the north pole of the earth, and the north pole of the earth’s magnetic field is close to the south pole of the earth. The geomagnetic pole does not coincide with the geographical north and south poles of the earth. The Earth’s magnetic field is very similar to the kind of magnetic field that is assumed to be generated by a giant bar magnet deep inside the Earth.