指南还是指北

One of you asked this question. “Does a magnetic compass point to the North Pole?” The answer is … not exactly. The North Pole is the spot on Earth’s globe that marks the northern end of an imaginary stick Earth spins around. Magnetic north is something else. A compass points to magnetic north – which is often in northern Canada. At a recent science meeting, EarthSky caught up with Stefan Maus, who studies Earth’s magnetism at the University of Colorado. He told us that magnetic north is moving at a speed of 50 kilometers – about 30 miles – every year. He said that scientists nowadays use satellites to track the changes.

前段时间有观众向我们提问：“罗盘的指针真的指向北极吗？”事实并非如此。北极是地球表面与假想的自转轴相交的北交点。磁北极就是另一回事了。罗盘的指针指向磁北极——通常位于加拿大北部。最近一次科学大会上，节目组采访了科罗拉多大学地磁研究员斯特芬．茅斯。他告诉记者，磁北极每年以50千米（约30英里）的速度移动，如今科学家使用人造卫星追踪磁极移动的轨迹。

Stefan Maus: They’re equipped with very sensitive magnetometers that measure the direction and strength of the magnetic field and that altitude.

斯特芬．茅斯：科学家们采用非常灵敏的磁力计来测量地磁场的方向、强度及方位。

He said scientists incorporate the measurements into magnetic field models. Many people now use this information while searching for directions on cell phones and GPS units.

他表示，科学家已将测量数据导入磁场模型。现在许多人的手机和GPS设备上都能应用这些信息进行导航。

Stefan Maus: Another example is that cameras will have magnetic field sensors, because you will want to know later not only where you took that picture, but also which direction you took the picture.

斯特芬．茅斯：另一个很好的例子就是未来的照相机可能会安装磁场传感器，这样人们不仅能了解相片的拍摄场地，还能得知拍摄的方向。

He said that our world’s magnetic field might influence your life even more in the years ahead, as more and more personal devices are equipped with compasses.

茅斯说，随着越来越多的私人设备上安装了罗盘，地磁场势必给人们的生活带来更深远的影响